wastewater treatment and management in northern canada - 2011 edition

Wastewater Treatment and Management in Northern Canada

Technical Publications of Ken Johnson, M.A.Sc., MCIP, P.Eng. and Co-authors cryofront.com

February, 2011 Revision

Wastewater Treatment and Management in Northern Canada

Technical Publications by Ken Johnson, M.A.Sc., MCIP, P.Eng., and Co-authors Revision 2011 02

1. Wastewater Sampling Challenges in Grise Fiord and Other Northern Communities. Published in

the Journal of the Northern Territories Water and Waste Association, 2010. 4 pages.

2. Fort Resolution Wastewater Treatment Improvements. Published in the Proceedings of the Annual Conference of Western Canada Water and Waste Association, 2010. 10 pages.

3. Giant Mine Water Management System. Published in the Journal of the Northern Territories Water and Waste Association, 2010. 4 pages.

4. Sewage Composting in Iqaluit Nunavut – Black Gold. Published in the Proceedings of the Annual Conference of Western Canada Water and Waste Association, 2009. 11 pages.

5. Dawson City Digs Deep for Sewage Treatment. Published in Western Canada Water, Fall,

2009. 2 pages. 6. Diavik Diamond Mine Water Management Plan. Published in the Journal of the Northern

Territories Water and Waste Association, 2009. 5 pages. 7. Water and Sewer Challenges in Kashechewan, Ontario. Published in the Journal of the Northern

Territories Water and Waste Association, 2009. 6 pages.

8. Advancing Wastewater Treatment in Inuit Regions of Canada. Published in the Proceedings of the Annual Conference of Western Canada Water and Waste Association, 2008. 12 pages.

9. A Brief History of the Past 60 Years of Northern Water and Waste. Published in the

Proceedings of the Annual Conference of Western Canada Water and Waste Association, 2008. 7 pages.

10. Cambridge Bay, Nunavut, Wetland Planning Study. Published in the Journal of the Northern

Territories Water and Waste Association, 2008. 4 pages. 11. Aerated Lagoon in the Canadian North – Fort Nelson BC Facility. Published in the Journal of

the Northern Territories Water and Waste Association, 2007. 5 pages.

12. The Social Context of Wastewater Management in Remote Communities, Published in the Proceedings of the Annual Conference of the Western Canada Water and Waste Association, 2007. 9 pages.

13. Engineered Improvements to Sewage Treatment System in Cambridge Bay, Nunavut. Published

in the proceedings of the Annual Conference of the Canadian Society for Civil Engineering, 2007. 8 pages.

14. Application of Large Scale At-Grade Sewage Treatment and Disposal in Fort Good Hope, NT. Published in the Proceedings of the Annual Conference of the Canadian Society for Civil Engineering, 2006. 7 pages.

15. Integrated Waste Management in Iqaluit, Nunavut. Prepared for Consulting Engineers of

Alberta Award Application, September, 2006. Received Award of Merit, Municipal Engineering Category. 8 pages.

16. Livingston Trail Environmental Control Facility, Whitehorse, Yukon. Published in the Journal of

the Northern Territories Water and Waste Association, 2005. 5 pages.

17. Performance and Potential Improvements to Anaerobic Sewage Lagoon in Fort McPherson, NT. Published in the Proceedings of the 12th International Cold Regions Engineering Specialty Conference, 2004. 14 pages.

18. The Future of Wastewater in a Global Water Shortage. Published in Environmental Science and Engineering. May, 2004. 2 pages.

19. Land Use Planning and Waste Management in Iqaluit, Nunavut. Published in Proceeding of the Annual Conference of the Canadian Institute of Planners. July, 2001. 3 pages.

20. Technologies for Use in On-Site Wastewater Recycling within Cold and Remote Regions.

Cryofront Journal of Cold Region Technologies. Published in 2000. 10 pages.

21. Sewage Treatment Systems in Communities and Camps of the Northwest Territories, and Nunavut Territory. Published in the Proceedings of the 1st Cold Regions Specialty Conference of the Canadian Society for Civil Engineering, 1999. 10 pages.

22. Evaluation of the Impact of Secondary Sewage Discharge on the Aquatic Environment of

Kodiak Lake Near Ekati Diamond Mine, NT. Published in the Proceedings of the 1st Cold Regions Specialty Conference of the Canadian Society for Civil Engineering, 1999. 10 pages.

23. Design and Construction of Sewage Lagoon in Grise Fiord, Nunavut. Published in the

Proceedings of the 7th International Conference on Permafrost, 1998. 8 pages.

24. Preliminary Engineering of Sewage Disposal System in the Community of Repulse Bay, Nunavut. Published in the Proceedings of the Annual Conference of the Canadian Society for Civil Engineering, 1994. 10 pages.

25. Performance Evaluation of Primary Sewage Lagoon in Iqaluit, Nunavut. Published in the

Proceedings of the 7th International Cold Regions Engineering Specialty Conference, 1994. 8 pages.

For more information about cold region technology contact: Ken Johnson, M.A.Sc., MCIP, P.Eng. CRYOFRONT “Cool Ideas” for Management –Technology – Media T: 780 984 9085 F: 780 460 7247 E: [email protected] www.cryofront.com

mailto:[email protected]

Wastewater Sampling Challenges in Grise Fiord and Other Northern Communities

Ken Johnson, M.A.Sc., P.Eng., AECOM

Edited from 2007 2008 Summer Sampling Final Report, Canada Wide Strategy for the Management of

Municipal Wastewater Effluent - Northern Research Working Group, Dillon Consulting Limited

Introduction

The rollout of the Canada Wide Strategy for the Management of Municipal Wastewater Effluent

continues to advance with the February 2010 announcement by Canada's Environment Minister that a

draft of proposed municipal wastewater systems effluent regulations were available for public

consultation. It was noted in the press release that "once in force, these regulations will set standards

for the discharge from all wastewater facilities in Canada. Over time, wastewater facilities across the

country will have to meet these national standards. It will no longer be permitted to directly release raw

sewage into our waterways." The announcement failed to mention that the Northwest Territories and

Nunavut did not endorse the legislation at the time of endorsement by the Yukon and the provinces in

February 2009. A big gap remains in the practicality and fairness of this legislation for the far north

regions of Canada, in particular the Inuvialuit Region of the Northwest Territories, Nunavut, the

Nunavik Region of Quebec, and the Nunatsiavut Region of Labrador.

In fairness to the rollout of the legislation, a research program to quantify the performance of existing

wastewater systems in the far north is on-going, and has a five year reporting mandate. However, in

addition to the basic process performance challenges with northern wastewater treatment, the research

program has identified a number of logistical challenges that may overshadow the actual

implementation and monitoring of the legislation.

2008 Sampling Program Results

The purpose of the 2007/08 sampling program was to identify the current wastewater treatment system

configurations and performance in northern communities, where the proposed Canada Wide Strategy

(CWS) for the management of municipal wastewater effluent may apply. The strategy includes national

performance standards for the release of total suspended solids (TSS), and carbonaceous biochemical

oxygen demand (CBOD) in wastewater effluent.

A total of 39 community were visited during the sampling program, 22 communities in the Northwest

Territories, 13 communities in Nunavut, and 3 communities in the Nunavik Region of Quebec. In each

community information was collected on the wastewater system, and wastewater samples were taken,

when possible, in the various cells of the systems, and at the discharge of the system into the

environment. These samples were tested for a full suite of chemical and biological parameters.

Sample results were analysed and compared to the proposed CWS effluent quality standards of 25 mg/L

for TSS, and 25 mg/L for CBOD. The sampling results indicated that 16 of 25 wastewater effluent

samples collected (64 percent) DID NOT meet the proposed CWS standards for TSS, and 10 of 16

wastewater effluent samples (63 percent) DID NOT meet the proposed CWS standard for CBOD.

A very interesting note to the sampling results is that the researchers identified that the "representative

sites" should meet a variety of criteria which include:

easy access to and from Yellowknife for prompt laboratory analysis of samples; and

definitive and accessible sample locations for raw, primary secondary and final effluent

Sampling Timeframe and Temperature Challenges

The report on the 2008 sampling program noted various challenges in acquiring representative

wastewater samples in each of the communities of the study including meeting the laboratory "holding

time" for time sensitive sampling, keeping the samples cool, access to the sampling locations and

defining the location for obtaining representative samples, particularly the so-called "end of pipe."

"Holding time" is defined by the difference between the time of sampling, and the time at the beginning

of the laboratory analysis. Bacteriological analyses must meet a maximum 24 hour holding time, and

BOD and CBOD analyses must meet a maximum 48 hour holding time. Most communities in the NWT

and Nunavut are difficult to access for the purpose of sampling because planes only fly and out on

certain days of the week, and seasonal weather can isolate a community for days at a time. A related

challenge to getting a sample back to the lab within the maximum holding time required by CBOD, BOD

and bacteriological analyses is that samples sometimes need to be taken at odd hours of the day (or

night) in order to "catch the plane."

Most water samples require cooling between the time of sampling and the time at the beginning of the

analysis. The reason for lowering the temperature is to reduce any ongoing biological or chemical

activity that would normally occurs in a sample, which will change the composition of the sample. By

cooling the sample, the lab results should reflect the composition of the water sample at the time of the

sampling. When samples arrive at laboratory, they are placed in a refrigerator holding room that is

maintained close to 4 C. While in transit between community and laboratory, samples are placed in a

cooler with ice packs to reduce the temperature. In order to ascertain how consistently cold

temperatures were maintained throughout the longest transit period in the 2008 study, temperature

monitors called "thermistors" were placed in the sample coolers originating from Grise Fiord, Nunavut .

The temperature spikes that reached 10 C occurred when the sample cooler was opened to put in more

waste water samples.

Sampling Access Challenges

Accessing wastewater sampling locations was a definite challenge for the 2008 study . Many locations

were either completely inaccessible or very difficult to access. Notably 22 % of the communities did not

have access to the receiving water body of the wastewater system effluent.

In addition, the location of the end of pipe is still not clearly defined in CWS, and samples were taken at

the likeliest location of the end of pipe. Many of the community samples had a wetland treatment as

part of their treatment process, therefore the end of pipe was not clearly defined, creating a challenge

to identify and access to the final discharge point . For the majority of the samples taken from 39

community, there was not a clear a location for the end of the effluent discharge pipe.

Conclusions

Biological systems at the mercy of the natural environment (such as sewage lagoons, and wetlands) are

inherently variable regardless of latitude. If excessive cold temperatures are thrown into the mix, then

biological systems are inherently unreliable for consistently meeting a prescribed low target, such as the

CWS guidelines. The results from the 2008 sampling study clearly demonstrate this fact, with over 60

percent of the samples not meeting the CWS standards for TSS and CBOD.

The logistical challenges for moving "stuff" around the north is intuitive for anyone who has done work

in the north. A minimum 5 day timeline for transporting wastewater samples from Grise Fiord was

documented. Temperature variations that "bounce all over the place", were also documented and

these temperatures are well outside the criteria for valid process monitoring within the CWS framework.

This information alone challenges the validity of using the CWS standards in the north. Add to this mix

the reality that only 50 percent of the sampling points are accessible, and the argument against the

current CWS framework in the far north is strengthened.

Figure 2. Travel journey for wastewater sample

from Grise Fiord temperature showing

time and temperature.

Figure 1. Sewage lagoon in GriseFiord, Nunavut – Canada’s most northerly municipal wastewater treatment facility.

Figure 3. Sewage lagoon in Ulukhaktok(Holman), NWT.

Figure 4. Accessibility of lagoon sampling points

across the north.

WCW Conference & Trade Show Calgary September 21 – 24 2010

FORT RESOLUTION WASTEWATER MANAGEMENT STUDY

Tricia Hamilton, AECOM

Ken Johnson, AECOM

ABSTRACT

In response to concerns expressed by community members, community stakeholders, and

regulatory authorities, the GNWT retained AECOM, to complete a wastewater

management planning study in Fort Resolution. The concerns with the wastewater

management were the capacity and environmental impact of the existing system, as well

as the requirements and cost for improving and replacing the existing system.

The existing sewage lagoon system is a facultative/infiltration process consisting of six

cells linked by channels. Wastewater ultimately percolates through the sandy soil in a

northerly direction to the wetlands approximately 400 metres from site. Detention in the

lagoon, and the infiltration process through the sandy soil provides treatment of the

wastewater.

The sewage lagoon is approaching the end of its service life with its current

configuration, as indicated by decreasing available freeboard. To meet the 20-year

wastewater generation demand, a new lagoon should be constructed using the same

facultative/infiltration process as the current lagoon. The volume of the new lagoon

should be approximately 18,000 m³, with a depth of 3 metres. The cost of the new

facultative/infiltration lagoon is estimated to be approximately $900,000.

COMMUNITY INFORMATION

The community of Fort Resolution is geographically situated on Resolution Bay and

immediately south of the Slave River delta. It is located at 61° 10' 16" N latitude and

113° 40' 20" W longitude, approximately 145 km southeast of Yellowknife. Fort

Resolution is accessible by road, and is approximately 160 km by road from Hay River.

The community is located approximately 160 metres above mean sea level and 4 metres

above the Great Slave Lake. The land to the east and south of Fort Resolution has a

gentle slope towards Great Slave Lake.

The surficial soils are mainly deltaic, however, to the north of the community this pattern

is interrupted by several massive outcrops of limestone bedrock. Fort Resolution is within

the southern margin of the discontinuous permafrost zone, and as such, shallow

permafrost is expected in undeveloped, forest-shaded areas. The climate in Fort


Figure 1. Fort Resolution Area

Resolution may be characterized by long cold winters and short cool summers. The daily

average temperature is -2.9 C. The July mean high is 21.1°C and the mean low is

10.6 C. The January mean high is -18.4 C and mean low is -27.6 C.

Fort Resolution currently uses a waste management site (sewage and solid waste) located

approximately 1.5 km north of the community centre. This site is located approximately

0.9 km east of the Fort Resolution airport, and this present-day site was first put in use in

approximately 1979.

Raw water is pumped from Great Slave Lake through a submerged intake line into a wet

well beneath the truck fill station; the truck fill station is located on the northwest edge of

the community. The raw water is treated with a package water treatment plant before

discharge into the water trucks which delivers approximately 80 m³/day of potable water

to the community.


Surface water runoff south of the airport ridge will likely discharge into Resolution Bay,

and north of the airport ridge will discharge into Nagle Bay. Both bays ultimately

discharge into Great Slave Lake.

A subsurface hydrogeological drilling investigation was conducted in the vicinity of the

current waste site in 1992. Piezometers were installed to monitor and sample

groundwater, and the water depth was found to be 1 to 2 metres below the ground

surface. The soil characteristics were reported to be fine-grained sand for the first 3

metres below grade, sand and with silt layers to from 3 to 6 metres, and clay with sand

and silt below 6 metres. The results of this hydrogeological investigation concluded that

the groundwater flow gradient is toward the wetland located some 500 metres north of

the waste site. The report also concluded that effluent flow from the lagoon into the

groundwater system should take approximately 12 years to reach the wetland north of the

waste site.

SEWAGE INFRASTRUCTURE

The sewage collection in Fort Resolution is contracted out with an annual contract value

of approximately $150,000. Sewage is collected from 225 buildings around Fort

Resolution and trucked 1.5 kilometres to the current lagoon site. The sewage is then

emptied into the laoon at the truck dump on the north side of the lagoon. Approximately

12 to 15 trucks with 9,100 litres of sewage are collected in the community each day, five

days a week.

Fort Resolution's sewage lagoon operates as a facultative and infiltration (soil absorption)

lagoon. In the warmer seasons, while retained in the facultative lagoon, sewage will

undergo biodegradation by bacteria, algae and plants. Sun and wind-mixed oxygen near

the surface of the lagoon permit photosynthesis and aerobic (oxygen-consuming)

reactions. Anaerobic (oxygen-deficient) degradation can also occur in deeper areas of the

lagoon.

Due to the porous, sandy soils around Fort Resolution's lagoon, sewage flows down into

the soil matrix and may percolate through the unsaturated soil layer into the saturated soil

(groundwater). The wastewater will then enter the groundwater flow. As sewage

infiltrates through the soil, treatment occurs.


Figure 2: Infiltration Lagoon

The unsaturated zone is the layer of soil between the ground surface and the water table.

This zone has efficient treatment capabilities through filtration, biodegradation,

absorption and adsorption; these processes will decrease coliform bacteria, biodegradable

material, nitrogen and phosphorous. Studies suggest that the ideal unsaturated zone is

between 0.9 to 1.2 metres of soil. However, a significant reduction of coliform bacteria

has been measured in approximately 30 centimetres of unsaturated soil.

The saturated zone is the wet soil below the groundwater level. The saturated zone also

facilitates treatment through filtration, biodegradation, absorption and adsorption,

although not as efficiently as the unsaturated zone. In addition, denitrification may also

occur, where organic carbon is available.

The groundwater table at the Fort Resolution site is very high; therefore the available

unsaturated soil depth is limited. However, the saturated soil zone is extensive, both

below the lagoon site, and to the north of the lagoon site toward the wetland area.

Ultimately, the saturated flow discharges to a wetland system approximately 400 metres

north of the sewage lagoon over a time period of approximately twelve years. This

wetland system ultimately discharges into Nagle Bay, and from there into Great Slave

Lake.

Fort Resolution's sewage lagoon consists of a series of six cells. The first cell (the most

northerly) was excavated in approximately 1979, and additional cells were sequentially

excavated to the south during the history of the site usage (1979 – 1981, 1985 – present),

whenever the lagoon appeared to be reaching capacity or when fill material was needed.

The cells were constructed using an excavator; after a cell was constructed, a channel was

excavated to connect the cell to the rest of the lagoon system.


Figure 3. Fort Resolution Sewage Lagoon Configuration

Based upon the population projection outlined, the generation of sewage waste is

estimated currently to be 77 m³ per day and in 20 years the generation rate is estimate to

be 84 m³ per day.

Wastewater generated in Fort Resolution is primarily domestic in source and

characteristics. The wastewater quality from the community may be considered to be a

"high strength" waste because of the use of a trucked sewage and water system. The

"high strength" condition is typical for trucked sewage and water systems due to the low

water usage, which results in a low dilution of the raw sewage.


Table 1: Wastewater Characteristics of the Sewage Lagoon

Parameter Unit

Fort Resolution Sewage Lagoon

Truck Dump

(2008)

Cell 6

(2008)

5-Day Biochemical Oxygen

Demand (BOD5) mg/L 421 151

Total Suspended Solids mg/L 224 190

E. Coli MPN/100 mL 1,600,000 110,000

Total Coliforms MPN/100 mL >1,600,000 1,600,000

Ammonia-N mg/L 66 23.8

pH pH Units 7.2 7.4

From the truck dump in Cell 1 to Cell 6, the sample analysis demonstrates a 93%

reduction of E Coli; a 64% reduction in BOD5; a 64% reduction in ammonia; and a 15%

reduction in suspended solids. The relatively low reduction in suspended solids is a

result of the algae growth in the lagoon, which is responsible for the BOD5 and ammonia

reductions.

These reductions in BOD5, suspended solids and coliforms demonstrate that the retention

in the facultative lagoon contributes significantly to the overall wastewater treatment

process.

A water sample was collected from standing water in the area north of the lagoon, prior

to the wetland system, which may be representative of groundwater characteristics as the

sewage lagoon effluent ultimately discharges into the wetlands. The laboratory analysis

for this sample is presented in as "Surface Water Near Wetland".

The BOD5 and nitrogen (in the form of ammonia) concentrations for the truck dump and

for Cell 6 are included in Figure 4 for comparison purposes, and are representative of the

wastewater quality before the effluent infiltrates into the soil. The BOD5 and ammonia-

nitrogen values may be indicative of the potential impact of the sewage lagoon on the

groundwater system as the groundwater moves toward the wetland.


421

151

36

4

66

24 190

0

50

100

150

200

250

300

350

400

450

Truck Dump

(2008)

Lagoon

(Cell 6)

(2008)

Groundwater

Average

(1992)

Surface

Water Near

Wetland

(2008)

Sample Location

Co

nce

ntr

atio

n (

mg

/L)

BOD5

Ammonia Nitrogen

Figure 4: BOD5 and Nitrogen in Ammonia Concentrations

These results indicate a significant overall nitrogen removal from the lagoon system

through the groundwater system, as well as significant removal from the groundwater

average around the lagoon to the surface discharge near the wetland. The results also

indicate a significant reduction in the BOD5 value from the groundwater average

concentration to the surface water concentration, demonstrating that significant

degradation occurs as wastewater travels down gradient with the groundwater.

It should be noted that these observations are based upon a very limited number of

samples, two samples taken from the lagoon in 2008, an average of groundwater samples

in 1992, and one sample of standing water (representative of groundwater conditions

discharging into the wetlands) in 2008.

The existing sewage lagoon configuration is nearing the end of its operating capacity.

From site observations of freeboard (distance from the water level to the top of the

lagoon pond) at the truck fill station on June, 2008, there was approximately 0.55 metres

of freeboard remaining in the lagoon.

LAGOON DEVELOPMENT

Fort Resolution’s current sewage lagoon is nearing the end of its capacity, and Fort

Resolution requires a new sewage lagoon. While desludging the current lagoon would

remove some biosolids, it would not effectively remove the interface of sludge


preventing sewage from infiltrating into the ground. Excavating a new lagoon cell in the

existing system will extend the life span of the current lagoon, but after that time

infiltration rates will once again slow and the community will once again have to address

this problem.

Fort Resolution’s sewage lagoon was excavated with limited engineering consideration.

Cells have been excavated when the lagoon nears capacity or when fill material is

required. This is a problematic method of operating a sewage lagoon facility.

Facultative / Infiltration Lagoon

The efficiency of an infiltration sewage lagoon decreases over time due to sludge build-

up. Solids settle in the bottom of the lagoon, forming a low permeability barrier that

reduces the available surface area for wastewater to infiltrate into the surrounding soil.

The sludge should be periodically removed from the lagoon ('desludged') to allow better

infiltration of the lagoon.

Figure 5: Two-Celled Infiltration Lagoon With Cobble Berm

One method of reducing the impact of sludge build-up in a lagoon is to have a 'settling

cell'. This is a lagoon system consisting of two engineered lagoon cells, where the

smaller, first cell provides retention time for solids in the sewage to settle before flowing

to the second cell, where infiltration occurs.

Due to the cold northern climate, having the cells be connected with a pipe or channel is

problematic. A cobble berm separating two cell will reduce the risk of freezing blockage

over winter. The top of the cobble berm will be below the outside perimeter, to allow

sewage to travel over the cobble berm into the second cell should the permeability of the

cobbles be reduced. This design will lessen the impact of sludge build-up on infiltration

rates, and desludging may only be required in the first cell.


A geotechnical and engineering investigation is required to determine the depth to

groundwater and verify hydraulic loading rates. To allow for wastewater to percolate

through the unsaturated soil matrix, the lagoon should not intersect the groundwater table.

The sewage lagoon should be at least 30 centimetres above the groundwater table. Thus,

the lagoon may have to be extended above ground through use of berms.

Lagoon Sizing

As infiltration rates are expected to significantly decrease during colder months, the

lagoon must be sized to be able to retain the community’s wastewater production for

seven months from October until April. Wastewater infiltration is expected to primarily

occur in the warmer months from May until September, the projected 2027 sewage

production of 30,702 m³ (2027 annual generation rate) must have the capacity to infiltrate

into the soil over five months.

Thus, the lagoon must have a capacity of at least 17,910 m³ to be sized for 20 years

(2027). For aerobic treatment of sewage while retained in the lagoon, the lagoon should

be no more than 3 metres deep. As such, to provide a volume of 17,910 m³, an area of at

least 5,572 m² is required.

The hydraulic loading rates of the soil at the Fort Resolution waste site was determined

to be in the range from 1.7x10-5

cm/s (0.0147 m³/m²day) to 4.6x10-3

cm/s (3.97

m³/m²day). The average loading rate of 6.7 x 10 4

cm/s (0.58 m³/m²day) is used for this

calculation.

Due to higher solids content, wastewater loading rates are estimated to be between 10%-

15% of hydraulic loading rates. An average of 12.5% of the hydraulic loading rate was

assumed for the wastewater loading rate for Fort Resolution. Therefore, the wastewater

loading rate is estimated to be 8.38 x 10-5

cm/s (0.0725 m³/m²day).

The annual loading rate is calculated by multiplying the wastewater loading rates by the

number of days infiltration is anticipated to occur (May until September). Thus the

annual loading rate is predicted to be 11.03 m³/m² year. Given that the annual sewage

production in 2027 is predicted to be 30,702 m³, to provide sufficient infiltration capacity

the lagoon must be at least 2,783 m².

A 3 metre deep infiltration lagoon with a volume of 17,910 m³ and an area of 5,970 m²

should provide sufficient volume and area for cold weather retention and warm weather

infiltration of Fort Resolution's wastewater.

If the settling cell is 10% the volume of the infiltration cell, the settling cell should have a

volume of 1,791 m³ and an area of 597 m².


Thus, the size recommended is a 3 metre deep lagoon with a volume of 17,910 m³ and an

area of 5,970 m². The actual length and width of the lagoon can be selected to best

account for site conditions and tree clearing requirements.

CONCLUSIONS AND RECOMMENDATIONS

Fort Resolution's sewage lagoon, composed of six cells excavated as required, is nearing

capacity with very little freeboard. The current site has successfully operated for

approximately 25 years and there is plenty of available land space in the area. A

redevelopment of the current site and improved operation and maintenance practices may

address community concerns regarding the site location.

Water samples were obtained during the course of this study, and it was observed that

while retained in the lagoon there was a significant reduction of E Coli, BOD5 and

ammonia concentrations. Groundwater and surface water samples suggest a significant

reduction in nitrogen and BOD5 concentrations attributed to the infiltration process.

Wastewater from the lagoon experiences aerobic treatment while retained in the lagoon,

infiltrates the sandy soil, where treatment occurs in the soil matrix, and enters the

groundwater flow to the wetlands approximately 400 metres north. During retention time

in the wetlands, further treatment occurs due to natural biological activity and settling.

As the soil in Fort Resolution is porous sand historically capable of handling the loading

of the community's sewage which discharges with the groundwater into a wetland, a

facultative/infiltration lagoon is recommended. A facultative/infiltration lagoon is also

less expensive ($0.90 M) than a retention lagoon ($1.7 M).

Giant Mine Water Management System Ken Johnson, AECOM NOTE: This project received the prestigious Award of Excellence from the Consulting Engineering of Alberta as part of the Showcase Awards 2010 History of Yellowknife Gold Mining The history of Yellowknife is intrinsically linked to its start as a mining town. When gold was discovered on the shores of Great Slave Lake and the claims were staked, Yellowknife was born as gold mining boomtown. The two most longstanding and productive mines, the Con and Giant Mines, were a result of the original exploration. Con closed underground operations in 2003 after 65 years of production and Giant closed underground operations in 2005 after 60 plus years of production. Both mines have left significant legacies on the shores of Great Slave Lake. The rock mined at Giant is rich in gold and arsenopyrite, a mineral that has a high arsenic content. The gold extraction process used at Giant required a „roasting‟ process to extract the gold from arsenopyrite rock. Arsenic trioxide dust was created during the production of more than seven million ounces of gold between 1948 and 1999. When the ore was roasted to release the gold, arsenic was also released as a gas. As the gas cooled, it became arsenic trioxide dust. Over a fifty year period 237,000 tonnes of toxic arsenic trioxide was produced, which is still being stored to depths of nearly 250 metres (800 feet) below ground in various shafts and chambers. Arsenic trioxide is water soluble containing approximately 60% arsenic, therefore it is critical to maintain the stored material “high and dry” to ensure that arsenic is not released into the environment. This effort requires that the groundwater be maintained below the 250 metre level through an automated dewatering pumping system. Managing the Giant Mine Arsenic Trioxide

Almost all of the arsenic trioxide at Giant Mine is stored in 15 underground chambers and stopes (irregular, mined-out cavities) cut into solid rock. Concrete bulkheads, which act as plugs, seal the openings to these chambers and stopes. The arsenic trioxide dust is totally surrounded by solid rock.

Due to the extensive mining, the permafrost around Giant thawed, and water began seeping into the storage chambers, becoming contaminated, with the potential of entering the groundwater systems. In response to this new issue, the water is pumped from the mine to a treatment facility on the surface. The contaminants in the water are removed through a treatment process before the water is released into the environment.

When this underground storage method was originally designed, it relied on the area's natural permafrost, which worked as a frozen barrier. It was believed that when the time came to close Giant Mine, permafrost would reform around the storage chambers and stopes, and seal in the arsenic trioxide. A 1977 report by the Canadian Public Health Association concluded that the underground storage of arsenic trioxide dust at Giant Mine was acceptable.

When the mine permanently closed some stakeholders wanted the arsenic trioxide removed from the mine and shipped elsewhere, away from Yellowknife's 18,000 residents. Citing risks to workers and the environment, INAC settled the solution of reestablishing the permafrost around the underground chambers and into a big deep-freeze, locking the dust into an eternal deep freeze. Integral to what is referred to as the "Frozen Block Alternative" is the automated dewatering pumping system to maintain the groundwater below the underground chambers.

In 2005, AECOM was retained by Public Works and Government Services Canada to provide planning and design of a new mine de-watering pumping system for the Giant Mine. With the mine closure, cleanup and remediation efforts have been completed in the lower portions of the underground works and it is no longer necessary to keep the mine de-watered below the 850ft. level. Water enters the mine as groundwater seepage and surface run off. The mine water level is held at the 850 ft. level by the automated mine de-watering pumping system. De-watering System Hydraulics and Pumping Mine de-watering is maintained by pumping the mine water from the 850ft level to surface at the historic Akaitcho headframe, in two separate pumping lifts. The lower lift portion of the pumping system uses a duty standby set of parallel submersible pumps installed within HDPE carrier pipes in an inclined mine shaft. These pumps lift water approximately 30 meters to a sump located on the 750ft. level of the mine. The sump is configured to provide “dirty” and “clean” cells by using a series of concrete weirs placed across an abandoned mine drift. This sump provides a suction volume to the high lift pumping system that moves water from the 750 ft. level to the surface in a single lift. Once at the surface the water flows to a retaining pond for subsequent treatment. The high lift pumping system uses a duty standby set of parallel 250 hp. multi-stage centrifugal pumps. Both the low lift system and the high lift systems are matched in pump capacity in order to provide a total de-watering flow rate of 275 cubic meters /hr. Construction of De-watering System The mobilization of materials to the project site up to 850 feet below the ground surface was a major challenge, particularly since the mine is no longer in full operation The contractor responsible for the work was Deton Cho / Nuna. which also has the “Care and Maintenance” contract for the mine. Construction of the sloped sections of the water line from 850 feet to 425 feet would have been a routine exercise for pipe fitting contractors, however, the contracting resources available for the work were ex miners, therefore the work

proceeded slowly in the initial part of the project. As the work advanced, the contractor employed pipe fitting expertise and the work progressed much faster. Construction of the vertical section from 425 feet to the ground level was difficult because it required construction from the bottom up, which meant that 6 metre pipe sections were lowered down the Akaitcho Shaft and sequentially added to the lower section and supported to the shaft wall. Access for this section of the work was challenging for the contractor because all of the steps and landing down to 425 feet were wooden construction dating back to the 1950‟s in some cases. Commissioning the dewatering system was held to a critical milestone of catching the spring runoff inflow. The work was ultimately completed in November, 2008 for a total cost of $3,000,000 (CDN).

Figure 3. Section of lowliftpipeline

Figure 1. Akaitcho Headframe at the top of the Akaitcho Shaft where highlift pumping system exits mine

Figure 4. Profile of Giant Mine water management system

Figure 2. Access vehicle and access shaft to Giant Mine

WCW iqaluit paper KJohnson CMcCracken 090630 Page 1 of 11

WCW Conference & Trade Show ▪ Winnipeg ▪ September 20 - 23 ▪ 2009

Sewage Composting in Iqaluit, Nunavut – Black Gold

Ken Johnson Cortney McCracken AECOM

ABSTRACT

In the Canadian north, municipal sewage sludge has been virtually ignored because of the predominance of lagoon wastewater treatment systems. The application of mechanical sewage treatment systems in Nunavut, and an increased regulatory scrutiny over the past 15 years have created a demand for sewage sludge handling, treatment, and disposal. The City of Iqaluit, Nunavut has been working toward the implementation of a secondary sewage treatment system since 1998, and with it the need for sludge management. This is an ambitious goal for the community considering the inherent challenges to the design, construction and operation of facilities in the harsh arctic environment.

Conventional municipal sewage treatment uses physical, chemical, and biological processes to separate solids and biological contaminants from municipal wastewater. Solids in the sludge are typically processed in a digester system, in which biodegradable materials are “digested” into stable organic matter. Sewage sludge may be further treated through dewatering, heat drying, alkaline (lime) stabilization, composting, or other processes.

Freezing and thawing, as an efficient method of sewage sludge conditioning, has been used for many years in cold climates. The final separation is achieved when the “released” water drains away from the solids after thawing, leaving a porous sludge with solids content of 20 to 30%. Following this dewatering and drying process, composting may provide stabilization and destruction of pathogens. The composting process requires the addition of bulking materials such as wood chips and cardboard pieces.

The City of Iqaluit landfill facility has been able to divert sewage biosolids from the first phase of the wastewater treatment plant. The process for the biosolids is to dry the solids throughout the long winter making use of Iqaluit’s cold dry weather, and compost the dried solids during the short warm summers to produce a cover material for the landfill. This process is attractive because the finished material is non-hazardous, and will reduce the use of precious granular material at the landfill - granular material may cost over $40 per cubic metre in Iqaluit.

Managing sewage sludge through freeze-thaw-composting is not without its challenges, but the City of Iqaluit has successfully completed a pilot program. Where other municipalities take for granted the technologies available to them, the arctic must re-engineer the process to suit the environment.



INTRODUCTION

The City of Iqaluit, Nunavut is in the process of upgrading to a conventional activated sludge wastewater treatment system for its municipal sewage. The first phase of the project (primary treatment) was commissioned in May 2006, and the second phase (secondary treatment) is planned for the next five (5) to ten (10) years. The design, construction, and operation of this facility present challenges that are unique to Iqaluit’s harsh arctic environment. One of these challenges is how to dispose of the sewage sludge produced by the sewage treatment facility.

Sewage sludge, produced as a waste product during modern sewage treatment, has specific handling, treatment and disposal requirements. Sludge has high levels of pathogens and high nutrient characteristics, so sludge must usually be treated before disposal in order to protect public health and the receiving environment. Most municipalities in Canada are aware of the need to treat sewage sludge before disposal.

However, sewage sludge treatment in the Canadian north is not well established. Municipal sewage sludge in the north is hidden as an inherent part of a sewage lagoon. Sludge essentially becomes part of the lagoon as it settles to the lagoon bottom, and only requires removal every 10 (ten) to 15 (fifteen) years. With such infrequent sludge disposal, it is easy to ignore municipal sewage sludge entirely. In addition, sludge management techniques used in more southern climates are not necessarily effective in the Northwest Territories and Nunavut because of the challenging environmental and social conditions.

The City of Iqaluit recognized the need for a sewage sludge management plan, and initiated a study to identify available sludge management technologies, and then apply screening criteria to produce a short list of technologies for detailed evaluation. These technologies were reviewed for their applicability in a northern context, and it was recommended that freeze-thaw dewatering and composting was the most appropriate choice for Iqaluit.

With freeze-thaw dewatering and composting selected as the sludge treatment processes, the City applied for funding to begin a pilot project in order to determine how effective the technology would actually be for Iqaluit's sewage sludge. The Federation of Canadian Municipalities (FCM) approved the City's grant application for equipment and testing. A pilot dewatering and composting facility was constructed next to the landfill in 2006.

Following through on the FCM grant the City of Iqaluit needed to determine the effectiveness of the sludge management pilot project. It was proposed to do this by analyzing samples of the compost and comparing these samples to the raw sludge. To this end, composted sludge samples were taken from the pilot sludge management area in October 2008, along with raw sewage sludge samples from the site. Samples of Iqaluit's raw sewage sludge were also taken in March, May and June of 2006.



SLUDGE COMPOSTING PROCESS

The sludge management facility is located next to the municipal landfill. Raw sludge is piled at the east end of the site, and four (4) composting piles (windrows) are established on concrete slabs towards the west end of the site. The area is fenced, with two gated entrances: one direct access through a gate from the road on the west side of the site, and an access road from the main gate at the landfill entrance.

Freezing and thawing is used to dewater the raw sewage sludge. During spring and fall months, the sludge freezes and thaws, which separates the solid sludge particles from the water. When complete thawing occurs from May to June, some of the separated water drains away. This freeze-thaw process produces a dryer sludge material available for composting.

To begin the composting process, dewatered sludge is mixed with wood chips (produced by shredding) at a ratio of approximately 2:1 wood: sludge, and piled in rows. The compost should be turned regularly to encourage aerobic conditions inside the pile. Over the summer months, composting will occur, and a "maturing" phase can occur over the following winter months.

SAMPLING RESULTS

2008 Samples

On October 28, 2008 samples of raw sludge and composted material were collected from the City's sludge management facility. Figures 1 and 2 show the sampling locations.

Figure 1: 2008 Sample Locations

The sample results were received by AECOM on November 11, 2008. Table 1 shows the results for the 2008 compost and sludge samples.

Sludge #1 Compost

#1 Compost

#2 Compost

#3

Sludge #2



Figure 2: Iqaluit Pilot Sludge Management Site Overview

Table 1: October 2008 Sample Results

Parameter Unit Compost #1

Compost #2

Compost #3

Sludge #1 Sludge #2

Aggregate Organic Constituents Organic Matter %

weight 10.8 8.3 8.6 84.2 91

Water % 32.1 Solids % 67.4 Oil (dry wt.) % 0.68 Oil (wet wt.) % 0.46 Classification Nitrogen (TKN) % 0.35 0.29 0.32 0.35 0.28 Phosphorus mg/kg 1620 1410 1470 2090 1340 Microbiological Analysis Total Coliforms MPN/g <3 7 43 >1,100,00 23000

1 The low organic matter result for Sludge Sample #2 may be an anomaly.



Parameter Unit Compost #1

Compost #2

Compost #3

Sludge #1 Sludge #2

0 Fecal Coliforms

MPN/g <3 7 7 1,100,000 23000

Physical and Aggregate Properties Solids (wet wt.) % 55.7 56.2 60.9 19.6 44.8 Soil Acidity pH 7.4 EC (sat. paste equiv)

5.66

EC (soil: water) 2.75 Water Soluble Parameters BOD (extractable)

mg/kg 3400 104000

2006 Samples

Initial samples of raw sludge from Iqaluit (the WWTP or the sludge management site) were taken in March 2006, May 2006, and again in June 2006.

The conclusions from this sampling were:

1. Untreated Iqaluit sludge has a high concentration of total solids (around 20%) compared to typical primary sludge (around 6%).

2. Untreated Iqaluit sludge contains a high concentration of Total Coliforms and Fecal Coliforms, with >1,100,000 MPN/g measured for both parameters in both the March and June samples.

3. Untreated Iqaluit sludge contains a low concentration of metals compared to typical wastewater sludge.

The sludge sample taken in March 2006 was analyzed for many different parameters, including various trace metals. The results can be compared to those of the Compost #1 sample taken in 2008, as shown in Table 2.



Table 2: Comparison of Compost and Sludge on All Parameters

Parameter Unit Compost (2008) Sludge (2006)

Aggregate Organic Constituents Organic Matter % weight 10.8 NT Water % 32.1 80.2 Solids % 67.4 17.6 Oil (dry wt.) % 0.68 11 Oil (wet wt.) % 0.46 2.16 Classification Nitrogen (TKN) % 0.35 1.08 Metals Mercury mg/kg 0.12 0.08 Aluminum mg/kg 6190 NT Antimony mg/kg 3.1 0.4 Arsenic mg/kg 5.1 0.4 Barium mg/kg 69 24 Beryllium mg/kg 0.2 0.2 Bismuth mg/kg 3.3 NT Cadmium mg/kg 1.11 0.17 Chromium mg/kg 27.7 2.7 Calcium mg/kg 17700 NT Cobalt mg/kg 5.1 0.2 Copper mg/kg 283 170 Iron mg/kg 18800 NT Lead mg/kg 87.9 3.9 Magnesium mg/kg 3400 NT Manganese mg/kg 282 NT Molybdenum mg/kg 4 2 Nickel mg/kg 19 2.2 Phosphorus mg/kg 1620 1420 Selenium mg/kg 0.6 0.9 Silicon mg/kg 680 NT Silver mg/kg 1.4 1 Strontium mg/kg 64 NT Thallium mg/kg <0.05 0.1 Tin mg/kg 6 2 Titanium mg/kg 213 NT Vanadium mg/kg 15.5 1 Zinc mg/kg 357 200



Parameter Unit Compost (2008) Sludge (2006)

Microbiological Analysis Total Coliforms MPN/g <3 >1,100,000 Fecal Coliforms MPN/g <3 >1,100,000 Escherichia coli MPN/g 1,100,000 Physical and Aggregate Properties Solids (wet wt.) / Total Solids % 55.7 19.5 Soil Acidity pH 7.4 5.6 Water Soluble Parameters BOD (extractable) mg/kg 3400 39500

*NT: Not Tested

DISCUSSION

Microbiological Content

The composting process is reducing the number of total and fecal coliforms to a great extent. As shown in Table 3, the Most Probable Number of both total and fecal coliforms is very high in Iqaluit's raw sewage sludge; lower in a sample of sludge that has undergone a freeze-thaw dewatering cycle; and very low in the composting material. Both the 2008 and 2006 sample results were used to generate the averages in Table 3.

Table 3: Total and Fecal Coliforms in Iqaluit Sludge and Compost

Units Average Raw Sludge Dewatered Sludge Average Compost

Total Coliforms

MPN/g > 852,500 23,000 18

Fecal Coliforms

MPN/g > 852,500 23,000 6

The US Environmental Protection Agency (US EPA) classifies sewage sludge as either Class A or Class B with respect to pathogen content. Either of these classes of treated sludge can be land applied. Compost is considered Class B if the temperature of the compost is raised to 40˚C or higher for five (5) days or longer, and the temperature exceeds 55˚C for at least four (4) hours during this period. The operating temperature of Iqaluit's compost piles during the summer is unknown.



0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

Average of 4 Sludge Samples Dewatered Sludge Average of 3 CompostSamples

Solid

s C

onte

nt (%

)Iqaluit’s treated sludge (compost) is either Class A or Class B with respect to pathogens. One of the alternative ways for a treated sludge to be classified as Class B is if the average fecal coli form count of seven samples is less than 2,000,000 Most Probable Number per gram of total solids (dry weight basis). Iqaluit’s compost is well below this limit for fecal coliforms, so the compost is at least Class B. There are also several alternatives for a treated sludge to classify as Class A, such as having low test counts for certain pathogens. This has not been examined in detail for Iqaluit’s compost.

Solids Content

The freeze-thaw dewatering process, combined with the composting treatment stage, appears to be effective at increasing the solids content of the sludge material. Raw sewage sludge from Iqaluit's WWTP is about 20% solids. As noted in the April 2006 letter report, this is higher than typical for primary sludge which is generally about 6% solids. After the sludge undergoes freeze-thaw dewatering and is mixed with dry wood chip material, the average solids content of the composting material is 58%.

One of the October 2008 sludge samples appears to have advanced in the freeze-thaw dewatering cycle, since the solids content is 44.8%, while four other sludge samples have solids contents of 18, 19.5, 19.6 and 20.9% respectively. This could indicate that the freeze-thaw process is successfully dewatering the sludge. However, no firm conclusions can be made about the effectiveness of the freeze-thaw process due to the limited number of samples.

Figure 3: Solids Content



Metals Content

It was observed that the Iqaluit March 2006 sludge sample had low concentrations for several key metals. The following charts compare the metals concentrations in Iqaluit sludge and compost. The metals concentrations measured in the October 2008 compost sample were somewhat higher than concentrations in the March 2006 raw sludge sample.

A rational explanation for this increase may be the source of the wood waste, which is shredded wood products and contains metal associated with nails and fixtures.

Figure 4: Metals in Sewage Sludge

The metals shown above have an impact on how a treated sludge (biosolid) may be used or disposed of. Except for tin, these twelve (12) metals are considered "of principle concern" in biosolids used for land application by the Ontario Ministry of Environment (1996). Ten (10) of them are regulated by the US Environmental Protection Agency (EPA) for sewage sludge to be used in land application.

USEPA pollutant limits for sewage sludge are shown in Table 4. Treated sludge must be below the Ceiling Concentration limits for any land application. For application on agricultural land, forest, a public contact site, or a reclamation site, the sludge must meet a more stringent Monthly Average Concentration, or else the application of sludge must be limited by a maximum cumulative pollutant loading rate in kilograms per hectare.

0

5

10

15

20

25

30

Arsenic

Cadmium

Chromium

Cobalt

Mercury

Molybd

enum

Nickel

Seleniu

m Tin

mg/

kg

Sludge Sample, March 2006 Compost Sample, October 2008

0

50

100

150

200

250

300

350

400

Copper

Lead Zinc

mg/

kg



Table 4: US EPA Pollutant Limits for Land Applied Sewage Sludge

Land Application2 Surface Disposal3

Pollutant Units Ceiling Concentration

Monthly Average Concentration

Maximum Concentration

Arsenic mg/kg 75 41 73

Cadmium mg/kg 85 39

Chromium mg/kg 600

Mercury mg/kg 57 17

Molybdenum mg/kg 75

Nickel mg/kg 420 420 420

Selenium mg/kg 100 100

Copper mg/kg 4300 1500

Lead mg/kg 840 300

Zinc mg/kg 7500 2800 Iqaluit’s sludge (treated and untreated) is well within the US EPA limits as shown in Table 4. Therefore, based on trace heavy metals content, the compost is suitable for land application.

CONCLUSIONS

Based on the sampling to date, the freeze-thaw dewatering and composting processes are effectively treating Iqaluit’s sewage sludge. Compost samples showed a dramatic reduction in total and fecal coliforms compared to the raw sludge samples. As well, the solids content of compost samples and one partially treated sludge sample was much higher than that of the raw sewage sludge. The processes do not appear to have any significant impact on some contaminants, including metals, but this result is expected.

It is worth noting that the metals concentrations in Iqaluit's sewage sludge and compost are below the US EPA limits on sludge for surface disposal and land application. Iqaluit's treated compost has very low pathogen counts, and likely could be classified as Class B sewage sludge or even Class A. This means that the treated compost is suitable for land disposal and some types of land application.

2 Land applications are defined as the spreading of sewage sludge onto land to condition soil or fertilize vegetation. 3 Surface disposal is defined as placing sewage sludge on an area of land for final disposal.



RECOMMENDATIONS

It is recommended that the City of Iqaluit continue to use freeze-thaw dewatering and composting to treat the sludge from its Wastewater Treatment Plant. These processes are successfully reducing the microbiological content and increasing the solids content of the sewage sludge. In addition, the technology is cost-effective and requires a modest amount of work to operate and maintain, particularly when compared to other technologies.

Based on a cursory examination of US EPA sewage sludge use and disposal regulations, Iqaluit’s treated sewage sludge (compost) is suitable for use as a cover material at the landfill. With a potential savings of $40 to $60 per cubic metre by using composed sewage sludge instead of conventional granular landfill cover, Iqaluit’s compost may be considered black gold.

Water Reuse & Recycling

Click here to return to Table of Contents44 | Western Canada Water | Winter 2009

Northern Systems

By Ken Johnson, AECOM

Dawson City digs deep for sewage treatment

Sewage treatment in Dawson City, Yukon Terri-tory has had an interesting history, and for the past 30 years a rather controversial one. Prior to 1979, sewage from Dawson discharged directly into the Yukon River, through a series of over a dozen independent wood stave pipe outfalls, without any treatment.

Sewage treatment entered the picture in 1979 with the completion of a “screening plant” that provided something better than preliminary treatment (the removal of two-by-fours and bicycles), but not quite primary treatment. This was a logical improvement to the sewage infra-structure serving Dawson City, and was followed by the replacement of much of the wood stave piping with insulated plastic (HDPE) piping.

From an environmental impact perspective, this improvement was not considered to be a significant improvement, but from an aesthetic perspective, the removal of the “floatable” component of the sewage was very significant. As well, the sewage discharge configuration was changed from the many shore discharges to a single submerged discharge near the centre of the Yukon River. The relocation and opportunity for increased dispersion of the sewage, through the current mixing regime, provided a significant public health improvement to the shore dis-charges. Dawson was apparently left alone until 1983, when they were first directed, as part of their water licence compliance, that they would have to clean up their act if toxicity could be established – and 26 years later this controversy still rages on.

Limited arguments were made that preliminary treatment did not go far enough in

There are strange things done in the midnight sun by the engineers who design for the cold,The arctic trails have their secret tails that will make your bid dollars explode,The arctic nights have seen queer sights, but the queerest they ever did see,Was the night on a nook of a Klondike brook there was a deep hole dug to treat Dawson “pee.”

(With apologies to Robert Service)

(Cartoon by Wyatt Tremblay was originally seen in the Yukon News. Used with permission.)

Click here to return to Table of Contents Winter 2009 | Western Canada Water | 45

Northern Systems

1979 to improve the effluent discharge into the Yukon. However, given the nature of the overall improvements at the time in Dawson’s water and sewer system (which included the complete replacement of all of the piped water and sewer and the elimination of the raw sewage discharges into the Yukon River) the improve-ments at the time were considered to be an appropriate increment.

Improvements to the Dawson City waste-water treatment system have been at various stages of planning over the past two decades, and the work advanced to the detailed design of a SBR system in 2003. However, the construc-tion of this system was never tendered because the estimated operation and maintenance costs exceeded $600,000 per year – this was unsus-tainable for a community with a permanent population of less than 2,000.

On the regulatory front, the pressure was maintained, and it reached a climax with a police raid on the Dawson City municipal offices in 2003. Dawson was subsequently charged under the Fisheries Act for the discharge of a deleterious substance, and court order was placed on the community. A judge has been monitoring the progress of the work ever since.

From an engineering perspective, the project switched gears, and aerated lagoon technology entered the picture. Aerated lagoon technology has been operating successfully in Alaska and in the northern reaches of the provinces, so the process was a logical alternative to mechanical treatment. The main obstacle was the level land on which to build the lagoon.

At first glance, Dawson appears to have a relative abundance of land, in spite of the mountainous terrain. However, with placer mining claims and aboriginal land claims, the abundant land is reduced to mere morsels. Ultimately, the lagoon option failed to advance when a land-use referendum vetoed the chosen site in 2008. The referendum put an end to the government’s proposed site for an aerated sur-face lagoon at the junction of the Dome Road and the Klondike Highway.

Instead of commissioning a consultant to complete yet another design, and then tender-ing it for construction, the Yukon Government charted a new course by issuing a design/build

request for proposals, where the solution and risk associated with the solution were put to the private sector. The outcome of the design/build process was the selection of Corix Water Systems as a proponent for an innovative solu-tion for Dawson City.

The key to the system proposed by Corix is the patented Vertreat process used by Noram Engineering. Vertreat is a technology that employs a “deep shaft” as the primary treatment vessel instead of the more common aerated basin at the ground surface. A similar system has been operating in Homer, Alaska for almost 20 years (see photo of Homer’s UV system above).

The advantages to the deep shaft ver-sion of an aeration basin were presented by Corix-Noram at a public information session in September in Dawson City. The system was described by Corix-Noram as being a good fit for an area where there are concerns about space limitations, extreme low temperatures, fluctuating sewage loads, seismic activity, and proximity to residential areas. Corix-Noram also claims that the Vertreat system uses about half the power of a conventional mechanical sewage treatment system.

In the operation of the Vertreat process, the influent is directed to a vertical 85 metre aeration shaft, where air is injected under high pressure, and supersaturates the influent with oxygen. From the aeration shaft the influent flows into a flotation clarifier, where the sewage sludge is separated before UV disinfection and discharge.

With the construction of the deep shaft, and the record setting capital cost of $25 mil-lion, Dawson City and the Yukon Government are “digging deep” literally and financially for the new wastewater treatment facility. In spite of the continuing controversy about waste-water treatment in Dawson City, Yukoners maintain their sense of humour. This was very clearly demonstrated by Wyatt Tremblay’s April cartoon in the Yukon News.


http://www.mequipco.com


Diavik Diamond Mine Water Management Plan Ken Johnson Published in the Journal of the Northern Territories Water and Waste Association. 2009. Dell Communications Inc. Ken Johnson - Editor Introduction The Lac de Gras watershed is a pristine region feeding into the Coppermine River which travels 850 kilimmetres to the Arctic Ocean at the community of Kugluktuk. This river is a world class Arctic Char fishery and a traditional harvesting are for the Inuit of the Kugluktuk Region. Lac de Gras is 60 kilometres long, with an average width of 16 kilometres and 740 kilometres of shoreline. The average depth of Lac de Gras is 12 metres, with a maximum depth of 56 metres. As an arctic lake it is cold year round, with temperatures ranging from 0 to 4 C in the winter and 4 to 21 C in the summer. Lac de Gras freezes in October and spring breakup is in July and the average ice thickness is 1.5 metres. Typical of arctic lakes, aquatic productivity in the lake is low because of the relatively low concentrations of nutrient, low light level during winter months with the ice cover and low water temperatures. The Diavik diamond mine is built on a large island in Lac de Gras, 300 kilometres northeast of Yellowknife, and has been operating since 2003. To prevent runoff from the site from entering the lake, the mine was constructed with an extensive water collection and treatment system. Through a system of sumps, piping, storage ponds and reservoirs, the mine collects run off water, which can be reused in processing or treated before being released back into Lac de Gras. Plant and surface operations water management requirements include:

North Inlet Water Treatment Plant (NIWTP) and North Inlet containment and outfall

Surface runoff and seepage pond system;

Potable water, sewage treatment, raw water and fire water;

Recycling and raw water use associated with the Process plant and the Processed Kimberlite Containment facility (PKC).

North Inlet Containment and Water Treatment Plant The North Inlet Water Treatment Plant (NIWTP), North Inlet containment , and the North Inlet outfall have the fundamental objective of treating water to meet compliance requirements prior to discharge to the environment. Waters directed to the North Inlet originate from:

Pit and underground inflows;

Surface runoff from North Inlet drainage basin;

Surface runoff from disturbed areas; and

Water transfers from the Clarification Pond. Water inflows are received at the North Inlet and then pumped to the NIWTP for treatment. The North Inlet has an estimated 2.5 million cubic metres of storage. The North Inlet provides surge storage capacity and allows some solids to settle before water is treated at the NIWTP. The NIWTP was designed to remove fine solids in cold water conditions. Major system components include coagulant and flocculant preparation equipment, two high capacity clarifiers, and four deep bed sand filters. The filters and pH-control system have not been required to achieve water license compliance, thus the NIWTP is operated with the clarifiers on a standalone basis. Bypassing the filters in the treatment circuit permits throughput to be increased from 20,000 m3/day to a maximum of 45,000 m3/day. Treated effluent is discharged into Lac de Gras via two submerged outfall and diffusers located 200 m offshore at a depth of 20 m. Surface Runoff Management Surface runoff historically occurs over a five month period from May to September. Runoff volumes depend on the particular weather conditions, and Diavik selected 1 in 100 year return conditions for sizing surface runoff collection systems. The surface runoff collection system consists of a network of ponds that collect runoff from the North Country Rock Pile, South Plant Site (Ponds 10, 11 and 12) and the PKC dam toes. Pipelines are permanently installed to permit transfer of waters from the collection ponds to the PKC facility. Collection ponds are designed to hold, without discharge to the environment, 100% of a 1 in 100 year return period freshet occurring over an 8 day period. As pond watershed surface areas will change over the life of the mine, the maximum watershed area was considered during pond design. Aircraft fueling and de-icing is performed on the airport apron, which is sloped toward the North Inlet. Fuel or de-icing spills would be directed to the North Inlet. Pond 3, located west of the North Country Rock Pile, collects seepage from the North Country Rock Pile and can be used as temporary storage for mine water. If water quality meets discharge criteria, it may be discharged to Lac de Gras; otherwise it is transferred to the North Inlet or the PKC facility. The pond water collection system was designed to transfer pond waters to the PKC facility. If collected runoff waters meet the water license quality limits, they may be discharged directly to Lac de Gras. Potable Water Supply and Sewage Treatment The potable water system consists of deep bed multi-media filters, polishing filters, and chlorine dosing. The raw water is supplied from the overall raw water supply system. The plant is sized to accommodate 800 persons.

Raw and fire water are pumped from Lac de Gras through distribution systems servicing the south plant site. The raw water system has a design capacity of 250 m3/hour, plus standby capacity. Flow demands include the process and recovery plant; a mobile equipment wash bay; and the potable water. The fire water system has a design capacity of 454 m3/hour plus standby capacity. The South Sewage Treatment Plant (SSTP) services the south plant site including operating facilities, the construction camp, and permanent accommodations. Sewage treatment capacity is designed to accommodate 800 persons at a design flow rate of 300 litres/person/day, for a total of 320 m3/day. The SSTP is an activated sludge system with tertiary filtration. Treated effluent is disinfected with chlorine. The WWTP discharge into the PKC system. Processed Kimberlite Containment (PKC) Facility Key objectives of the PKC facility and Process water management system to provide storage of processed kimberlite (PK); act as an equalization reservoir for supernatant water and runoff water for process plant re-use; and provide recycled water to the Process Plant. The Process and Recovery Plants are both the primary consumers and suppliers of water to the PKC facility. The plants consume reclaim water and raw water for ore processing, and generate coarse (1 mm to 6 mm) and fine (less than1 mm) PK. Coarse PK is transported by truck to the coarse PKC storage area, and fine PK is transported as slurry via an insulated pipeline to the PKC facility. The Process and Recovery Plants are designed to maximize reclaim water recovered from the PKC pond to minimize raw water use. Reclaim water is used for essentially all process services in the Process Plant. Conclusions The Diavik diamond mine is a unique world class operation, with world class water management systems. The water management demands on Diavik and the other diamond mines in the Canadian north have been high, but given the pristine nature of the environment, these demands were warranted.

Figure 1. The Diavik diamond mine on Lac de Gras is the headwaters of the Coppermine River which flows past historic Bloody Falls on its way to the Arctic Ocean.

Figure 2. Diavik is located on an island within Lac de Gras, and mines from dyked Kimberlite deposits within the lake.

Figure 3. The Diavik water management system schematic shows the extensive collection, reuse and treatment processes.

Figure 4. The Diavik water management system uses sumps, piping, storage ponds and reservoirs.

Water and Sewer Challenges in Kashechewan, Ontario Ken Johnson Published in the Journal of the Northern Territories Water and Waste Association. 2009. Dell Communications Inc. Ken Johnson - Editor Background Kashechewan is a Cree First Nations community of about 1,900 people, 10 kilometres upstream from James Bay on the Albany River in Northern Ontario. The community is located at 81 38 degrees west longitude and 52 17 degrees north latitude. The closest urban centre to the isolated town is Timmins, Ont., 400 kilometres to the south. The community lies on the flood plain of the Albany and many of its buildings are susceptible to flooding in the springtime. The climate of the Hudson's Bay Lowlands is of long cold winters and short warm summers. Permanent ice may appear between late Novembers and will provide cover until the end of April or early May. The terrain and vegetation are sub-arctic with a predominance of open cover of stunned black spruce and tamarack in the swamps and peat land. The banks of the Albany River, river in lands and tributary streams however, are forested with heavy cover of white spruce. A new water treatment plant was built for the community in 1995 to replace an existing plant that was at the end of its design life. October 2005, high E. coli levels were found in the reserve's drinking water, and a major evacuation of the community occurred with about 800 community's residents airlifted to the northern Ontario communities. Water Supply and Treatment The Kashechewan water treatment plant uses a surface source from Red Willow Creek. The creek feeds into the Albany River, which ultimately flows into James Bay. The water treatment plant is located at the mouth of Red Willow Creek. It is a conventional treatment plant with chemically assisted filtration and disinfection processes and is capable of producing approximately 1,400 cubic metres of treated water per day. The raw water intake for the plant is a 200 mm diameter pipe that extends approximately 90 m into the creek. The intake crib is located in the vicinity of where the creek feeds into the Albany River at a depth of 4.5 m. Water from the Red Willow Creek flows through the intake, and into a raw water intake well located on shore. From there, the raw water passes through a coarse screen to remove large debris or fish entering into the plant's low lift well. The water treatment plant intake in Red Willow Creek was positioned so that potential contamination from overflow of raw sewage from the sewage collection system into the Albany River would be minimized. Tides from James Bay do influence the flow of the Albany river, and in fact may cause some reverse flow in the river under certain circumstances.

From the low lift well, the water is pumped via two low lift pumps to the clarification treatment process in the plant. Coagulant chemical is added in the low lift well pump discharge pipe to aid in the settling of particulate matter in the raw water. Clarification water is pumped from the low lift well to the plant's single clarifier. A temporary polymer feed system is set up on the clarifier. Within the clarifier, the larger, heavier, particulate matter is allowed to settle to the bottom. The clarified effluent then flows into the plant's filtration system. Sludge at the bottom of the clarifier is discharged to the sanitary sewer. The filtration system at the plant consists of two (2) sand and anthracite media gravity filters. Water from the clarifier enters into a splitter box and proportionate water enters into each filter by gravity. The filtered water is chlorinated and flows into the plant's clearwell. The clearwell is comprised of two (2) separate cells, each with a volume of approximately 280 cubic metres. Treated water from the clearwell is pumped into the distribution system via five (5) high lift pumps. There is also one (1) fire pump for emergency services. Sewage Collection and Disposal The Kashechewan First Nation sewage collection system includes gravity sewers, three sewage lift stations and forcemains. The main lift station pumps the sewage across Red Willow Creek to the sewage treatment facility. The main lift station has an overflow to direct raw sewage to the Albany River via the overflow sewer should the lift station fail. The sewage treatment facility is located immediately north-east of the community, on the north-east side of Red Willow Creek. The community is located on the opposite shore. The facility consists of two individual lagoons. Lagoon 1 was constructed in about 1988, has an estimated working capacity of 83,000 m3. The working capacity of cell 2, constructed in about 2000, is approximately 104,000 m3. The lagoon cells were designed to discharge on a seasonal 7-day discharge basis, including one discharge period in the spring and one in the fall of each year. Treated effluent from the discharge chamber enters a ditch that leads to East Creek. East Creek flows in a north-easterly direction for a distance of approximately 8 km from the sewage lagoons towards James Bay. Concerns with Water and Sewer Infrastructure A comprehensive assessment was completed after the 2005 incident as a means to document the circumstances that lead up to the contamination event, and provide a framework for action to reduce the chances of a similar incident occurring in the future. The following observations were made regarding the water system at the time of the incident:

The water treatment system had inoperative valves, pumps and feed lines, including check valves on the supply piping from the low lift pumps; chemical metering pumps; and completely obstructed chemical feed lines.

There were no up-to-date record drawings available on site for either the water treatment plant or water distribution system, and there was no apparent documented procedure for the disinfection of drinking water at the water treatment plant.

An insecure bypass had been installed so that raw water could be directed around the clarifier to the filters and there were a number of potential cross-connections between treated and untreated process wastewater

There was limited process instrumentation for monitoring the operation of the water treatment plant.

The following observations were made regarding the sewage system at the time of the incident:

The overflow sewer was located adjacent to the shoreline of the Albany River, upstream of the surface drinking water supply intake within the Red Willow Creek. Tidal influences experienced in the area could potentially transport contamination along the shoreline of the Albany River and near the drinking water intake.

There was no dedicated standby power supply for the sewage collection system. This circumstance increases the potential for raw sewage to overflow to the Albany River during an extended power supply outage.

Two of the three sewage lift stations were non-operational. Under these conditions, if the remaining sewage lift station failed, there was the potential of an overflow of sewage to the Albany River.

The overflow sewer and associated backflow prevention device were broken; this could permit water to enter the sewage collection system, resulting in flooding of the community during high water levels in the Albany River.

Conclusions The lessons learned from Kashechewan are not unique, in fact the elements of the Kashechewan experience have been evident in many of the communities across the north at some point in time over the past 20 years. What is unique about Kashechewan is that a series of circumstances lead to an outcome and an action that received national attention. The Kashechewan story is far from over as the Federal government considers what long term action is needed to reduce the risk of an incident like this in the future, not only in Kashechewan, but other remote northern communities.

Figure 1. Community of Kashechewan and adjacent infrastructure

Figure 2. Kashechewan water supply and sewage treatment systems.

Figure 3. Schematic of Kashechewan water treatment processes.

Figure 4. Schematic of kashechewan sewage treatment system.

Protecting Our Water – 60 Years of Service 60th Annual WCWWA Conference and Trade Show September 23 – 26, 2008 Delta Regina Hotel Regina, Saskatchewan

ADVANCING WASTEWATER TREATMENT IN INUIT REGIONS OF CANADA Ken Johnson Earth Tech Canada Abstract The Inuit regions of Canada include the Inuvialuit region of the Northwest Territories, the Nunavut Territory, the Nunavik region of Quebec, and the Nunatsiavut region of Newfoundland and Labrador, and comprise a land area totaling about 40% of Canada's total land area with a population of approximately 41,000 individuals living in one of 53 communities. The regions are represented on a collective basis by the Inuit Tapiriit Kanatami (ITK). The continuing work the Canadian Council of Ministers of the Environment (CCME) on the Canada-Wide Strategy for Management of Municipal Wastewater Effluent has been largely ignored by the Inuit regions, not for a lack of potential interest, but for an absence consultation by the Federal Government. The ITK were finally brought into the fold of the consultation process in the fall of 2007 in advance of the stakeholder deadline of January 31, 2008. A flurry of activity occurred within the ITK and from various technical resources retained by the ITK in order to respond to this deadline with a meaningful and comprehensive position for the Inuit regions of Canada. The fundamental concern expressed by the ITK is that the strategy has a geographic and cultural bias that is inherent to the process of advancing from principles to practice in the proposed "roll out" of the strategy. A position paper was prepared and submitted by the ITK on January 31, 2008 which identified many deficiencies in the strategy as it applies the Inuit regions and the north in general, and recommended realistic timelines, funding for research into the science, applied science (engineering) and social science of arctic wastewater treatment. The position paper also recommended specific actions and financial needs for wastewater characterization, incremental improvements to wastewater treatment processes, research into "best appropriate technology", establishment of a regulatory framework, education and training, public education, and community consultation. With this position paper, and the extensive supporting documentation, it is the intent of ITK to influence the Government of Canada in its decision making, so it does not leave a legacy that will impact the well being of the Inuit across Canada for generations to come.


REGIONS AND COMMUNITIES Inuvialuit Settlement Region The Inuvialuit Settlement Region is located in the northwestern part of the Northwest Territories. The Inuit population is approximately 5,000 living in the mainland communities of Inuvik, Aklavik, Tuktoyaktuk, and Paulatuk and the two island communities of Sachs Harbour (Banks Island) and Holman (Victoria Island). Inuvik is the administrative centre for the region and has a total population of 3,400 of which 1/3 are Inuvialuit. Inuvik is the only Inuit community in Canada that has an all season connecting road to the south; the communities of Tuktoyaktuk and Aklavik have only a seasonal ice road. The communities of Sachs Harbour, Ulukhaktok, and Paulatuk continue to rely solely upon air and marine connections for transportation and supplies. Nunavut Nunavut has an Inuit population of approximately 23,000 people living in the regions of Qikiqtani (eastern region), Kivalliq (central region), and the Kitikmeot (western region). The territory's twenty-six communities generally have populations of around 1,000 or less. The regional administrative centres of Cambridge Bay in Kitikmeot, and Rankin Inlet in Kivalliq, have populations of 1,300 and 2,700 respectively. The territorial capital, Iqaluit, is the largest community with a population of over approximately 6,000. The primary method of transportation between the communities and the south is via air and marine vessels.


Qikiqtani Region of Nunavut The Qikiqtani region is located at the eastern part of Nunavut and includes Baffin Island, the eastern High Arctic Islands, and the Belcher Islands. The Inuit population of the region is approximately 12,000 living in 13 coastal communities: Iqaluit, Kimmirut, Cape Dorset, Hall Beach, Igloolik, Arctic Bay, Resolute Bay, Pond Inlet, Grise Fiord, Clyde River, Qikitarjuaq, Pangnirtung, and Sanikiluaq. Kivalliq Region of Nunavut The Kivalliq region lies on the western coast of Hudson Bay and includes Southampton Island. Just over 6,000 Inuit live in seven communities: Rankin Inlet, Repulse Bay, Chesterfield Inlet, Baker Lake, Coral Harbour, Whale Cove and Arviat. Kitikmeot Region of Nunavut The westernmost region of Nunavut has an Inuit population of 4,000 and includes the Boothia Peninsula and Victoria Island. The communities are Cambridge Bay, Kugluktuk, Umingmaktuuq, Bathurst Inlet, Taloyoak, Gjoa Haven and Kugaaruk. Nunavik Region The region of Nunavik lies north of the 55th parallel in the province of Quebec. Nearly 10,000 Inuit call Nunavik home and live in 14 communities including: Kangiqsualujjuaq, Tasiujaq, Aupaluk, Kangirsuk, Quaqtaq, Kangirsujuaq, Salluit, Ivujivik, Akulivik, Puvirnituq, Inukjuak, Umiujaq, and Kuujjuarapik. Kuujjuaq is the regional administrative centre with a population of approximately 2,300 residents. With a lack of roads connecting the communities, the primary method of transportation between them and the south is via air and marine vessels. Nunatsiavut Region Approximately 5,200 Inuit inhabit the five northernmost coastal communities of Labrador and the more southern communities of Happy Valley-Goose Bay, Northwest River, and Mud Lake. The coastal communities are Nain, Hopedale, Postville, Makkovik and Rigolet. Nain, with a population of 1,200, is the administrative centre for the northern coastal region. The primary method of transportation between the communities and the south is via air and marine vessels.

Northern communities and Inuit communities in particular, are unique in their "built environment" (see Figure 2). The communities have no road access (with the exception of three communities of the Inuvialuit region), limited access by water (during the ice


free season), and year round access by aircraft only. The proximity of the various components of infrastructure creates unique interactions.

The size of the majority of the Inuit communities is "very small" with daily wastewater flows of less than 500 m3/day (Reference: Environment Canada. October, 2007, page 8). The populations vary from the largest community of Iqaluit (population of 6000) in Nunavut, to the smallest communities, of Sachs Harbour, Inuvialuit Region, Grise Fiord, Nunavut Territory, Aupaluk, Nunavik Region each with populations less than 200 people.1

Climate, Geography and Terrain

The climate in the communities of each of the four Inuit regions is extremely cold, with the average yearly temperatures less than zero degrees C. The warmest average yearly temperate in the four regions occurs in Nunatsiavut region with a temperature of -3 C in Nain. The mean daily temperatures in July range from 5 to 10 C in the Inuvialuit Settlement Region, 5 to 10 C in Nunavut, 5 to 10 C in Nunavik and in the range of 5 to 15 C in Nunatsiavut. The extremely cold weather may be described further by the number of frost free days in the communities (see Table 1).

Table 1: Average Yearly Frost Free Days for Select Inuit Communities Region Community Average Yearly Frost Free Days Inuvialuit Sachs Harbour 57 Inuvialuit Inuvik 107 Nunavut Resolute 40 Nunavut Rankin Inlet 102 Nunavik Kuujjuaq 115 Nunatsiavut Nain 126

1 The population of 1000 associated with a "very small" system is defined by the typical waste generation

for a piped system (500 L/c/d), not a trucked system which is most commonly used in Inuit communities; based on a per capita waste generation of 90 L/c/d, a "very small" community may have a population of 5500 people.


The geography of the communities in the Inuit regions generally creates great distances between the individual communities themselves, and between the communities and major centres further south. The traditional activity of the Inuit and the development of permanent settlements have placed all but three of the communities along the mainland or arctic island coasts. The majority of the terrain in the Inuit regions of Canada is Canadian Shield, with smaller regions of Interior Plains and Arctic Lowlands. The Inuvialuit Settlement Region is primarily interior plains with a small area of Arctic coastal Plain. Nunavut consists of Canadian Shield and Interior Plains and Arctic Lowlands; the Kivalliq and Qikiqtani Regions are Canadian Shield terrain, and the Kitikmeot region is and Arctic Lowlands. Nunavik and Nunatsiavut are located in the Canadian Shield.


SOCIO-ECONOMICS Inuvialuit Region The Inuvialuit Region is a government region of the Northwest Territories; the government of the Northwest Territories (GNWT) is the senior government responsible for the delivery of services. Locally elected community councils oversee the administration and delivery of a wide variety of services to the hamlet residents in addition to the services delivered by the GNWT. The main employment in the Inuvialuit region is government related, however significant economic development has been provided by oil and gas activities. Nunavut The Government of Nunavut has an elected territorial legislature representing 23 electoral districts. The legislative assembly operates as a consensus government; therefore the premier is elected by the members of the legislature. Qikiqtani Region of Nunavut The economy of the region is based upon renewable resource harvesting including a commercial inshore and offshore fishery, arts and crafts, tourism, and the public and service sectors. The public sector is a major employer in the region. Kivalliq Region of Nunavut Renewable resource harvesting is a primary economic activity and includes a caribou and arctic char processing plant. Tourism has grown substantially in the region and there is some growing interest in mineral exploration as well. The public sector is a major employer in the region. Kitikmeot Region of Nunavut As well as renewable resource harvesting such as a commercial char fishery and musk ox harvest, the region has considerable mineral wealth that is in the process of being explored and developed. The public sector is a major employer in the region.

Nunavik Region

Renewable resource harvesting, the Xtrata nickel mine, tourism, the public sector, transportation and the service industry are all important elements of the regional economy. Each community has its local administration provided by municipal councils


as established by the Northern Village Corporation. Each Northern Village is part of the Kativik Regional Authority that oversees the administration of the region. The Kativik Regional Government is responsible for the delivery and coordination of municipal infrastructures and services, manpower and training, environmental issues and the coordination of economic policy. Nunatsiavut Region Locally elected Inuit community councils oversee functions and the provision of services to the municipalities. Harvesting of land and sea resources continues to be an economic mainstay of the region with government employment, fishing, and the service industry being primary employers. The Voisey's Bay nickel deposit has greatly increased the economic activity of the region. EXISTING WASTEWATER TECHNOLOGY, PERFORMANCE, COST AND OPERATIONS Only three of the 53 Inuit communities, namely Rankin Inlet, Pangnirtung, and Iqaluit, use mechanical sewage systems. The system in Rankin Inlet is preliminary treatment to remove large solids by screening. The system in Pangnirtung is secondary treatment using a rotating biological contactor. The system in Iqaluit has preliminary and primary treatment for the removal of solids by screening. Although designs for secondary treatment systems have been completed in Rankin Inlet and Iqaluit, construction of the advanced systems has not yet been authorized. All of these mechanical systems have significant operating challenges. Historically, all of the mechanical systems used in Inuit communities have failed at one point or another and communities have fallen back on the use of the simpler technologies of wastewater detention or retention (lagoon systems). Most of the remaining communities use lagoon systems which are either detention or retention ponds. Detention ponds provide a continuous discharge, and retention ponds provide a periodic discharge. Overall these systems tend to perform well because of the simple technology, although there are problems with undersized systems, maintenance deficiencies and poor operation practices. The five communities of Nunatsiavut directly discharge sewage into the ocean without any sewage treatment. It has been reported that lagoons and natural lakes perform reasonably well. The data is limited but indicates a Biochemical Oxygen Demand (BOD) reduction in the range of 87% to 96% (BOD less than 150 mg/L and as low as 11 mg/L), Total Suspended Solids (TSS) reduction in the range of 90% to 93% (TSS less that 80 mg/L and as low as 5 mg/L) and fecal coliform reduction in the range of 2 to 4 logs (fecal coliforms less than


2x106 and as low as 3x101). The influent sewage is estimated to be 600 mg/L BOD, 725 mg/L SS, and 107 coliforms/100 mL. The capital cost of lagoon systems in the Inuit communities are highly variable depending upon the location, granular materials available, competitiveness, and contractor experience and confidence. A lagoon constructed in Grise Fiord (population less that 200) in 1996 cost approximately $300,000; the current cost of this same lagoon would probably be closer to one million dollars In general terms, lagoon systems are multi-million dollar construction projects. The operation and maintenance of a lagoon system is also highly variable. In Grise Fiord, the annual cost for water and sewer was approximately $2240 per capita (see Table 2); the sewage portion of this cost was approximately $670 per capita.

Table 2: Grise Fiord, Nunavut Operation and Maintenance costs Year Water $ Sewer $ Total $ 2001 234,391 100,200 334,591 2002 255,959 109,696 365,655 $2,240 per capita per year in 2002 or 6.4 cents per litre for water and sewer Water use - 5,678,500 litres per year or 95 litres per capita per day From an operation perspective, any sewage treatment system, particularly mechanical sewage treatment systems have significant cultural and language barriers which must be addressed on a daily basis. The biological aspects of sewage treatment process are difficult to explain because Inuit have never heard words like clarifier or biomass. DISCUSSION A significant number of documents and presentations have been prepared in association with the Canada-Wide Strategy for Management of Municipal Wastewater Effluent, and the proposed implementation strategy by Environment Canada. These documents include:

• Canada-wide Strategy for the Management of Municipal Wastewater Effluents. September 2007.

• Proposed Regulatory Framework for Wastewater. October, 2007. • Review of the State of Knowledge of Municipal Effluent Science and Research:

Review of Existing and Emerging Technologies; Review of Wastewater Treatment Best Management Practices. January, 2006.

• Affordability of Wastewater Treatment Services in Canada. June, 2006


The documentation provides a comprehensive basis for advancing the harmonization of sewage effluent standards, but in a context that is grounded in southern Canada, and in a non-Inuit cultural context. Elements in the documentation must be challenged in order the guide the any future implementation of the effluent standards in Inuit regions of Canada. Canada-wide Strategy for the Management of Municipal Wastewater Effluents. September, 2007.

• Key Element of the Strategy: sustainable funding strategy; facility size; wastewater facility monitoring. Challenge – given the capital, and operation and maintenance costs associated with sewage treatment in Inuit regions, a realistic and sustainable funding strategy would have to be supported by senior governments; Inuit living in communities such as Grise Fiord cannot afford the current sewage cost of $670 per person per year.

• "due to extreme climatic conditions and remoteness of Canada's arctic, alternative performance standards …will be proposed within 5 years" Challenge – data collection and compilation for sewage systems in Inuit communities has been very limited in the past decades for reasons such as cost, human resources and the simple fact that samples often cannot be transported to laboratories in a timely manner; these same conditions will exist over the next years and into the foreseeable future, therefore it is not realistic to state that the necessary science to support alternative performance standards for Inuit communities may be completed within the next five years.

• "all wastewater facilities are required to monitor their effluent discharge" Challenge – Inuit communities do not have the administrative, financial, and human resources to undertake data collection and compilation for sewage systems; this fact has been demonstrated over the past several decades for reasons such as cost, as well, samples often cannot be transported to laboratories in a timely manner.

• "the term arctic is still under discussion…defining arctic include number of growing degree days, mean annual near surface ground temperature and number of ice-free days" Challenge – climatic conditions are highly variable across the arctic, particularly with the onset of climate change; rather than a climatic base for defining the arctic, a geographic base should be used for defining the arctic, which includes the Inuit regions of Canada.

Proposed Regulatory Framework for Wastewater. October, 2007.

• "authorize maximum effluent discharge levels of 25 (BOD and TSS)" Challenge – Inuit communities cannot consistently meet the effluent discharge levels of 25 mg/L for BOD and TSS with the lagoon technology that is the most appropriate to the various conditions in the Inuit regions.


• "timelines to achieve effluent discharge levels in regulations" Challenge – an extended timeline is not going to change the reality that Inuit communities cannot afford the capital, and operation and maintenance costs of any advanced sewage treatment technology without significant and sustained financial support from senior governments.

• "threshold acute concentration of ammonia versus pH" Challenge – temperature also influences the toxicity of ammonia and lower temperatures reduce the toxicity of ammonia; the low temperature environment of the arctic should be integral to the toxicity considerations for ammonia.

• "certain wastewater systems have constraints …. due to the extreme climatic conditions and remoteness of Canada's arctic" Challenge – climate and remoteness are only two of many constraints associated with the Inuit communities of Canada's arctic; the decision making must be made on the basis of science, applied science (engineering) and social science (administrative, financial and human resources).

Review of the State of Knowledge of Municipal Effluent Science and Research: Review of Existing and Emerging Technologies; Review of Wastewater Treatment Best Management Practices. January, 2006.

• "the operating an maintenance costs for mechanical treatment systems in the north are substantially higher… such consideration make these treatment process less acceptable to small/remote and northern communities" Challenge – operating and maintenance costs are more than "substantially higher"; the costs are potentially an order of magnitude higher than the south, and Inuit communities cannot afford these costs.

• "considerations in treatment level required include: habits, attitudes and social patterns of the residents of the community" (USEPA documentation) Challenge – these social science aspects of wastewater treatment are not an integral part of the considerations for the Inuit regions and should be.

• "case studies for small central US municipalities; recommendations include: develop in house training; form partnerships with larger regional cities; implement modest but consistent rate increases" Challenge – these recommendations do not apply to Inuit communities.

• "smaller and rural communities may have difficulty in attracting and employing dedicated wastewater treatment operators" Challenge – Inuit communities do have difficulty in attracting and employing operators particularly resources from outside the community.

• "it may be possible to retain private firms to offer operating and maintenance services" Challenge – private firms are not an option for operating and maintenance services in Inuit communities for the reasons of cost and retaining operators.


• "many technical resources are available through technical associations, government agencies and internet portals" Challenge – Inuktitut remains the first language of many residents of the Inuit communities, therefore the technical resources are not available to the communities, and may not be available for many years.

Affordability of Wastewater Treatment Services in Canada. June 2006

• "the average annual wastewater charge per household was calculated to be $185.35" Challenge – the value of $185 does not include any consideration of the costs in the Canadian arctic; the costs in the Canadian arctic are potentially an order of magnitude higher.

• "average annual household wastewater charges in Canada appear to be 'affordable' when compared against median annual household income" Challenge – the costs in the Canadian arctic are potentially an order of magnitude higher; Inuit cannot afford these costs without significant and sustained funding from senior governments.

CONCLUSIONS Inuit communities have limited resources available to them, and the reality of sewage treatment in the Inuit regions of Canada is that most communities can only make incremental improvements to their community sewage treatment infrastructure. Those systems which are technologically simple, and engineered for sufficient capacity tend to perform well. The majority of communities of the Inuit regions of Canada are "very small", very remote, and very cold; therefore the sewage treatment technology must be appropriate to these conditions and must be applied in the context of these conditions. The knowledge of the appropriateness and context for arctic sewage treatment may only gained through research in science, applied science and social science. Unless significant resources and commitment are applied the research into all aspects of arctic sewage treatment the Canada-wide Strategy for Management of Municipal Wastewater Effluent will have significant impacts and produce significant hardship on the Inuit regions of Canada. These impacts will be financial (capital cost and operation-maintenance cost), human resource, and administrative.


RECOMMENDATIONS

• The Canada-wide Strategy for Management of Municipal Wastewater Effluent must include a geographic definition of the arctic instead of climatic definition, which should include the Inuit regions of Canada.

• The Canada-wide Strategy for Management of Municipal Wastewater Effluent must have a realistic timelines, and funding for research into, and implementation of the science of arctic wastewater treatment.

• The Canada-wide Strategy for Management of Municipal Wastewater Effluent must have timelines, and funding for research into and the implementation of the applied science (engineering) of arctic wastewater treatment.

• The Canada-wide Strategy for Management of Municipal Wastewater Effluent must have a realistic timelines, and funding for research into and the implementation of the social science of arctic wastewater treatment.

• The Canada-wide Strategy for Management of Municipal Wastewater Effluent must have sustained funding for implementation of wastewater improvements based upon the science, applied and social science research.


A BRIEF HISTORY OF THE PAST 60 YEARS OF NORTHERN WATER AND WASTE Ken Johnson Earth Tech Canada ABSTRACT Over the course of the past sixty years water supply and waste treatment in Canada has changed dramatically, however the most dramatic changes have occurred in the northern regions of Canada. Sixty years ago much of northern Canada, particularly the smaller communities, were still based upon a subsistence economy and not a wage economy, therefore the infrastructure for water and sewer was essentially non existent. A select few communities, such as Dawson City, Yukon and Yellowknife, NWT had infrastructure in place as a result of the mining boom in each of these communities. The water and waste practices in the early days of small northern communities were very simple. Water was brought in by hand, from the nearest water source, "outhouses" were used for sewage waste, grey water was dumped adjacent to the houses, and garbage was burned in individual barrels near each household. One of the most significant infrastructure milestones in decade following World War 2 was the development of the community of Inuvik and its above ground piped water and sewer system, which was initiated by the chronic flooding and limited capacity of the nearby community of Aklavik. In 1957, John Diefenbaker's once-famous "northern vision" policy inspired the nation, and advanced further initiatives in northern infrastructure. Water and waste infrastructure in northern communities continued to make incremental improvements in the 1960's and 1970's as the subsistence lifestyles continued to decline, and more people moved to permanent settlements. Water and sewer tanks were becoming more common, along with indoor plumbing, but these were still limited, and there remained a significant need for engineered water supply and wastewater disposal systems. One of the most significant policy decisions concerning water supply infrastructure occurred in the mid-1980's with the recognition that intestinal disease could be correlated to water use. As a result, a policy was put in place that water supply infrastructure would be required to deliver a minimum of 90 L/c/d in each individual in a community. This policy initiated a concerted effort to provide indoor plumbing to each household, and phased out the use of honey bags for sewage disposal.


The turn of the 20th century in the north has brought regulatory demands into the forefront of community infrastructure, for the better and worse of northern communities. Continuing incremental improvements in water and waste infrastructure as a result of regulatory demands have benefited communities. On the other hand, regulatory scrutiny has placed many communities in positions where they have neither the financial nor human resources to address the regulatory demands. BEFORE 1948 Northern Canada has remained first and foremost the homeland for aboriginal peoples and a pristine environment. Attachment to the land and dependence on local resources for physical and spiritual sustenance are deeply rooted characteristics of the aboriginal cultural heritage. Each of the aboriginal groups identifies with a traditional territory, shaped by thousands of years of continuous occupation. The land mass itself is immense, covering almost 45% of Canada's land mass that stretches 4500 kilometres along the 60th parallel and 2800 kilometres north from the 60th parallel to the edge of the Ellesmere Island, which is just 800 kilometres south of the north pole.

Until the 1800's and into the early the 1900's, the economy was based solely on traditional activities of a nomadic lifestyle following an annual cycle set by the weather and the wildlife. This subsistence economy began to shift with the advent of whaling activities in the eastern Arctic, and the expansion of the fur trade into the North, making cash and trade goods important commodities for the aboriginal population. The shift continued with the establishment of permanent communities first by traders, and then missionaries; ultimately government institutions established a presence in the communities.

In the mid 1940's the citizens of Yellowknife and Aklavik installed surface water distribution systems to supply water to their houses during the summer. This was luxury for them, for the rest of the year they had to haul or carry water to their homes, and for rest of the communities of the Northwest Territories even summer only piped water system was a "pipe dream". In most of the communities, the people threw waste water on the ground near their doorway, and discarded toilet water and garbage a distance away to be disposed of by gull, raven and scavenging dogs. In a few larger communities toilet waste and garbage were hauled to isolated places nearby. Such were water, sewage and garbage serving in the Northwest Territories 60 years ago (from the Changing North by Jack Grainge, 1999).


DAWSON CITY INFRASTRUCTURE

One community was the exception to the rule regarding modern water and sewer infrastructure. Dawson City, Yukon was the largest city west of Winnipeg at the turn of the 19th century, and in spite of its extreme isolation had many amenities, including a piped water and sewer system. The engineering and construction resources for this infrastructure may be attributed to the placer mining resources in the community at the time. Dawson was in fact building extraordinary hydraulic projects as the need for water was driven by the placer mining activity.

The date of construction of the first components of the Dawson City water and sewer system is not known precisely, however, it has been recorded that Dawson had a water and sewer system in operation as early as 1904. A description of the system operation in 1911 states that "only three or four houses in Dawson were equipped with year-round running water. To prevent their freezing in winter, the water pipes had to be linked to parallel pipes of live steam which must be kept constantly hot. In addition, the water must be kept moving through the pipes continually and thence through an insulated outlet all the way to the river." The original pipe installations were wood stave construction, and this piping continued to be used until the 1970's (see Figure 1).

Figure 1: Wood Stave Piping Replacement in Dawson City Yukon (Circa 1970)

INUVIK INFRASTRUCTURE One of the most significant infrastructure milestones in decade following World War 2 was the development of the community of Inuvik and its above ground piped water and sewer system, which was initiated by the chronic flooding and limited capacity of the nearby community of Aklavik. In 1957, John Diefenbaker's once-famous "northern vision" policy inspired the nation, and advanced further initiatives in northern infrastructure.


In 1953, federal government survey teams fanned out across the Mackenzie Delta looking for a new spot on which to build the settlement that would replace Aklavik. They narrowed the choice to six on the east side and six on the west side of the delta. In November 1954 they picked East Three on the East Channel of the Mackenzie Delta, about 120 kilometres south of the Arctic Ocean. The large, flat area had a navigable waterway, room for expansion and wasn't subject to flooding each spring.

Construction of Inuvik began in 1955 and federal officials expected the town to be built by 1961 or 1962. It was the first time in Canada that a community would be built from scratch, giving new meaning to the term "government town."

Building on permafrost proved to challenge engineers and architects. They expected to find a metre of permafrost, but discovered that Inuvik sits on 350 metres of ground that is frozen year round. To prevent heat from warm buildings thawing the permafrost and causing them to sink, most structures sit on pilings drilled five metres into the ground with about half to one metre of space between the ground and the bottom of the building.

Inuvik's utilidor was originally constructed in one single enclosed conduit supported on wood piles; the utilidor included a dedicated pipe carrying high temperature hot water for buildings and freeze protection of the water and sewer mains (see Figure 2).

Figure 2: Inuvik Utilidor System (Circa 1960)


INCREMENTAL IMPROVEMENTS The water and waste practices in the early days of small northern communities were very simple. Water was brought in by hand, from the nearest water source, "outhouses" were used for sewage waste, grey water was dumped adjacent to the houses, and garbage was burned in individual barrels near each household. Water supply advanced to the use of summer water points during the warmer months instead of bringing water by hand from a lake or stream (see Figure 3).

Figure 3: Summer Water Point In Rae Lakes, NWT

Water and waste infrastructure in northern communities continued to make incremental improvements in the 1960's and 1970's as the subsistence lifestyles continued to decline, and more people moved to permanent settlements. Water and sewer tanks were becoming more common, along with indoor plumbing, but these were still limited. Newer homes were equipped with wastewater holding tanks located on or beneath the floor of the house into which drained household waste from kitchen sinks, laundry, bathroom and toilets would drain by gravity. These tanks were normally larger than the water storage tanks, with a minimum tank size of 1200 litres.. Trucked delivery for water and sewer was the standard level of service in all but a few communities. A handful of larger communities started to develop piped systems, and this started the process of advancing water and sewer technology specific to cold region conditions with the application of shallow bury, insulated pipes and recirculating water systems (see Figure 4).


Figure 4: Insulated Water and Sewer System in Rankin Inlet, Nunuvut (Circa 1980)

One of the most significant policy decisions concerning water supply infrastructure occurred in the mid-1980's with the recognition that intestinal disease could be correlated to water use. As a result, a policy was put in place that water supply infrastructure would be required to deliver a minimum of 90 L/c/d in each individual in a community. This policy initiated a concerted effort to provide indoor plumbing to each household, and phased out the use of honey bags for sewage disposal. Keeping up with the ever increasing water demand were engineered water supply and sewage treatment facilities. Water is an abundant resource in the north except for the fact it may remain frozen for over 6 months of the year. Access to a year round supply of water was a significant problem across the north which engineers solved by building large reservoirs with enough depth so the water would not completely freeze, and enough volume to accommodate what could be a nearly 2 metres of ice on the surface. The reservoirs were constructed of earth and lined with impermeable materials. Pumping systems adjacent to the reservoir fed truck fill points for distribution to the residents; chlorination equipment was provided as part of the truck fill station infrastructure. Sewage treatment and disposal followed suite with water supply, and sewage lagoons became the technology of choice because of low cost and ease of operation and maintenance. The application of mechanical sewage was very limited, and in fact the only one community, namely, Carmacks, Yukon had a mechanical treatment system until the 1990's.


THE FUTURE OF NORTHERN WATER AND SEWER The turn of the 20th century in the north has brought regulatory demands into the forefront of community infrastructure, for the better and worse of northern communities. Continuing incremental improvements in water and waste infrastructure as a result of regulatory demands have benefited communities. On the other hand, regulatory scrutiny has placed many communities in positions where they have neither the financial nor human resources to address the regulatory demands. Mechanical systems are becoming more common for water treatment, as senior governments work to meet national guidelines for drinking water quality. The continuing success of mechanical systems, particularly in small communities remains a function of the technical assistance provided by the senior levels of government. Small communities have limited financial and human resources for the operation and maintenance of complex water treatment systems. Lagoon systems remain the most common form of sewage treatment, in spite of demands for more sophisticated technologies. Improving upon the performance of lagoons is occurring with the application of wetlands for tertiary treatment. The key elements with the future of northern water and sewer are "appropriate technology", applied in a "northern context", and scheduled in an "incremental" timeframe.

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Cambridge Bay, Nunavut, Wetland Planning Study

Robert H. Kadlec, PhD., P.E., Wetland Management Services, Chelsea, MI Ken Johnson, M.A.Sc., MCIP, P.Eng., Earth Tech Canada Cortney McCracken, EIT, Earth Tech Canada

Published in the Journal of the Northern Territories Water and Waste Association. September, 2008. DEL Communications Inc. Ken Johnson – Editor.

Introduction

Cambridge Bay, Nunavut has been planning for upgrades to the sewage lagoon systems, which includes a wetland area. As part of the design stage, a wetland planning report was prepared to estimate the water quality improvement that this engineered wetland project would achieve.

The study provides a unique look at wetland water treatment in cold climates. Treatment in a wetland is generally the result of a number of processes, such as settling, filtration, and bacterial action. These are aided by the presence of wetland vegetation, which is expected to be relatively sparse at the Cambridge Bay wetland; however, such vegetation does now exist in the depression ponds within the proposed wetland footprint. Some of these processes (mainly biological) occur much more slowly in cold temperatures, and the calculated water quality improvement was based on information and models from more southern climates. However, it is possible to predict the biological treatment efficiency of the Cambridge Bay wetland by applying temperature coefficients, and using very low rates for biological processes, compared to rates used in warmer climates.

Proposed Lagoon and Wetland System

In 2005, the sewage treatment facilities at Cambridge Bay consisted of three natural lagoons totaling about 71,800 m3 capacity, and a limited wetland area. The Government of Nunavut realized that this existing sewage treatment system would not meet the needs of the projected population in 2020, and decided to investigate potential improvements to the lagoon system. Earth Tech Canada was retained for this planning related work.

The proposed configuration for the lagoon systems includes primary and secondary retention lagoons with 120,000 m3 storage volume, and constructed wetlands which will convey and further treat the water before discharge to the north arm of Cambridge Bay. The 2.93 ha wetland will be constructed by berming the flow path from the lagoons to the sea, and excavating to remove existing land features as needed. Discharge from the lagoons will be continuous during the summer season, of

Figure 1. Cambridge Bay sewage lagoon and wetland.

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approximately three months duration. During this time, the 3 hectares of wetland in the flow path of the effluent (estimated to be at a mean depth of 30 cm) will provide about two weeks of detention in the wetland (See Figures 1 and 2).

Wetland Forecasting Procedure

Constructed treatment wetland design generally involves three elements: hydrology and hydraulics; consideration of the pollutant and hydraulic loadings; and first order removal models. The Cambridge Bay forecasting

Figure 2. Cambridge Bay sewage wetland.

calculations were implemented via spreadsheets on a desktop computer, because of the level of detail required in the modeling procedure.

The first step in predicting the wetland performance was a seasonal water budget calculation to examine how much water is present at various points in the wetland. This procedure took into account variables such as rainfall, evaporation, and plant transpiration, as well as the inlet water flow.

The next step was a review of the influent contaminant loads based on data taken in prior years at the lagoon discharge point. The wastewater from the community is high strength, due to restricted use of water; however, the water reaching the wetlands will have much lower contaminant concentrations due to extended lagoon treatment. The contaminant removal achieved by the wetland was calculated using pollutant mass balances, which required the selection of removal rate coefficients for each contaminant.

Contaminant Removal Rate Coefficients

Suspended Solids

A major function performed by wetland ecosystems is the removal of suspended sediments from water moving through the wetland. These removals are the end result of a complicated set of internal processes, and some of these processes such as resuspension and “generation” of suspended material may increase the suspended solids at any point in the wetland. Temperature has little effect on suspended solids wetland treatment. Accordingly, an estimated rate coefficient of 50 m/yr was chosen, which is sufficiently high to drive the wastewater TSS down close to the background value of 10 mg/L.

Figure 3. Cambridge Bay CBOD performance.

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Carbonaceous Biochemical Oxygen Demand

The Cambridge Bay wetland is expected to receive moderate incoming CBOD5. As temperature effects have been found to be minimal, the rate coefficient was selected as 30 m/yr, which is the 40th percentile of the distribution across other wetlands. This rate coefficient is sufficiently high to drive the wastewater CBOD5 down to 9 mg/L under current conditions, and 16 mg/L for future flows in 2025 (See Figure 3).

Nitrogen

There appears to be little or no temperature dependence of organic nitrogen k-values. However, ammonia nitrogen removal in Cambridge Bay is likely to be achieved primarily by microbes which are very temperature sensitive. Therefore, relatively low rate coefficients were selected for nitrogen processing. The result is that the Cambridge Bay wetland shows lower TN removals than the comparison database, which reflects more southerly, warmer conditions (See Figure 4).

Phosphorus

Phosphorus is a nutrient required for plant growth. There are two direct

Figure 4. Cambridge Bay nitrogen performance

effects of vegetation on phosphorus processing and removal in treatment wetlands: the plant growth cycle seasonally stores and releases P, thus providing a “flywheel” effect for a P removal time series; and new, stable residuals are created, which accrete in the wetland (these residuals contain phosphorus as part of their structure, and hence accretion represents a burial process for P).

As most phosphorus removal is due to the burial of plant residuals, it is dependent on the size of the plant growth cycle, which is anticipated to be rather small for this far northern site. Accordingly, there will be a lower phosphorus removal at Cambridge Bay compared to southern wetland systems.

Pathogens

Wetlands have been found to reduce pathogen populations with varying, but significant degrees of effectiveness. Bacteria in wetlands can be killed by ultraviolet radiation, eaten by nematodes, rotifers and protozoa, or removed along with particles in settling and trapping. Based on currently available treatment wetland data, pathogen removal is apparently not dependent on season or temperature.

Estimated Wetland Water Quality Improvements

The new wetland system in Cambridge Bay is expected to complement the proposed lagoons, and provide good water quality improvement, especially for CBOD5 and TSS. Because of Cambridge Bay’s northern climate, CBOD5 and TSS removal are likely to be comparable to wetlands in other climatic regions, but nutrient removal will be less. Some removal of pathogenic organisms is anticipated, as there will be ample sunlight to promote UV disinfection in the wetland, as well as die-off due to cold temperatures. A two-log reduction (99%) is expected.

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The forecasts for water quality at the downstream end of the wetland are given in Table 1.

Table 1. Expected Water Quality into and out of the Treatment Wetland at Cambridge Bay

Current Conditions 2025 Conditions

From Lagoons Wetland Outlet From Lagoons Wetland Outlet

TSS mg/L 50 13 75 18

BOD mg/L 30 9 50 16

TP mg/L 2.5 2.1 2.5 2.2

Org-N mg/L 5 3.1 5 3.5

NH4-N mg/L 10 9 10 9

NOx-N mg/L 0.5 2.7 0.5 2.2

TN mg/L 15.5 14 15.5 15

TKN mg/L 15 12 15 13

FC #/100ml 1,000 70 1,000 100

Conclusions

The water reaching the Cambridge Bay wetland will have been subjected to very long detention in the lagoons, which will provide a good degree of water quality improvement. The wetland will then provide further water quality improvement, with particularly good results (results typical of southern treatment wetlands) predicted for CBOD5 and TSS removal.

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Aerated Lagoons in the Canadian North – Fort Nelson Facility Ken Johnson, M.A.Sc., P.Eng., Senior Planner and Engineer, Earth Tech Kriss Sarson, P.Eng., Program Manager, Community Services, Government of the Yukon Published in the Journal of the Northern Territories Water and Waste Association. September, 2007. DEL Communications Inc. Ken Johnson – Editor. Introduction Research on the application of aerated lagoons in the far north has been non-existent since facultative (non aerated) lagoons are the sewage treatment process of choice for most northern communities because of the cost effectiveness, simplicity of operation, and abundance of space available to most communities. This situation has been changing over the past decade as regulators have lobbied Water Boards, and pressured communities to improve effluent quality by applying conventional “southern” mechanical technologies. This evolution has exhibited mixed results with “new” mechanical systems operating in the northern communities of Fort Simpson, Rankin Inlet, Iqaluit and Pangnirtung. Although it may be said that these systems are generally operating in compliance with the water licence parameters, the communities are faced with a legacy of sustaining these processes with limited financial and human resources. New challenges are emerging for these communities because of the demands for managing the significant biosolids waste stream produced by the waste treatment process. Interest in the application of aerated lagoon systems in the far north is gaining momentum as regulators and senior governments recognize that this is appropriate technology based upon the successful operation of aerated lagoon systems in Alaska and the northern reaches of the provinces. The aerated lagoon system in Fort Nelson is one example of an aerated lagoon system operating in the near north, as well as aerated lagoon systems operating in northern Alberta, near Fort McMurray (See Figure 1)

Figure 1. Aerated lagoon near Fort McMurray.

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Aerated Lagoon Process and Configuration The aerated lagoon is a fairly straightforward, easy to operate technology that has been successfully used in cold climates. In the past, there was a degree of resistance to aerated lagoons in the North, primarily due to the higher energy costs and lack of appropriate cold climate aeration technology. Though higher energy costs are still a feature of operating costs in the North, aeration systems have been advanced sufficiently to allow for effective treatment in the North. Throughout the past forty years, a number of process models have been advanced that describe the overall size and treatment efficiency of aerated lagoons. For the most part, they rely upon first order kinetics, and are therefore dependant upon the correct selection of the values for k and θ. For lagoon applications, the value of k can range from 0.14 to 0.3 and θ can range from 1.06 to 1.12. The size of the lagoon cells is also a function of the influent and effluent Biochemical Oxygen Demand (BOD) concentrations, along with the influent flow rate. Combined, these factors equate to the overall BOD load being “processed” by the lagoon. The general configuration in an aerated lagoon uses a combination of completely mixed and partially mixed cells. A typical three cell aerated lagoon configuration is comprised of a completely mixed cell, followed by a partially mixed/plug flow cell, and then finally by a combination partially mixed/plug flow cell with a quiescent settling zone. The advantage of a three cell configuration versus a two cell system is process flexibility. It is advantageous to have the operating flexibility to take one cell out of service, while still maintaining effluent quality. This will become critical 20 or more years down the road, when cell desludging may be required. The process concept of an aerated lagoon system allows for a significant portion of the organic load to be taken up in the first cell (completely mixed), so for this reason a slightly higher reaction rate constant may be applied to this cell, and a more modest one for the subsequent partially mixed cells. With this type of model there is a degree of variability, and the effluent BOD values for each of the cells are approximated, along with the appropriate size of the cells. Other factors have to be considered with respect to the layout of the facility, such as subsurface conditions, site topography, ease of geo-membrane liner application, and the treatment plant building layout. In a conventional mechanical secondary wastewater treatment plants, aeration requirements are dictated by the process air requirements and not mixing requirements. However, in an aerated lagoon application, the opposite is true. The aeration for the lagoon cells is generally supplied by a fine bubble aeration system supplied by a defined number of process air blowers.

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Performance of Fort Nelson Aerated Lagoon The aerated lagoon system serving the community of Fort Nelson is example of the successful operation of an aerated lagoon in a cold climate (See Figure 2). The average performance for the aerated lagoon over the past 7 years (2000 to 2006) has maintained BOD and Total Suspended Solids (TSS) removal greater that 80 percent (See Table 1). Average effluent BOD5 and TSS has been less than 25 mg/L for both parameters for the years 2004, 2005, and 2006; average effluent fecal coliforms have been less than 40,000 CFU per 100 mL (See Table 2).

Figure 2. Fort Nelson aerated lagoon system. Table 1. Average Yearly Performance for Fort Nelson Aerated Lagoon Year Average %

BOD Removal Average % TSS Removal

2000 79 86 2001 68 92 2002 82 86 2003 83 84 2004 83 81 2005 83 88 2006 88 90 Average 81 Average 87

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Table 2. Average Influent and Effluent Quality for Fort Nelson Aerated Lagoon Year Influent

BOD5 mg/L

Effluent BOD5 mg/L

Influent TSS mg/L

Effluent TSS mg/L

Influent FC CFU/dL

Effluent FC CFU/dL

2004 140 24 147 22 3.0x106 17.1x103 2005 115 19 197 22 2.9x106 37.4x103 2006 133 17 200 19 2.0x106 1.3x103 Winter performance during the months of December through March (2000 to 2006) has produced an average BOD5 removal in the range of 70 to 93 percent, and an average TSS removal in the range of 72 to 98 percent. Table 3. Average Winter Temperatures in Fort Nelson November December January February March Average Temperature (degrees C)

-13.0 -19.9 -21.2 -16.1 -7.7

Advancing Applications of Aerated Lagoons in the Far North In 2004, Dawson City and the Government of the Yukon evaluated the application of aerated lagoon technology for producing a secondary non-toxic effluent compliant with the Fisheries Act, Water License and the Court Order. This work included a preliminary site selection and costing along with an aerated lagoon pilot test. Initial sites were selected for a 3 cell system comprised of 2 aerated cells (15 day retention each) and one facultative cell (60 day retention). The pilot plant results confirmed that an aerated lagoon had the potential to produce a non-toxic secondary effluent without the need for a facultative cell. This work was advanced to the preliminary engineering of an aerated lagoon system to serve Dawson City, and design work may proceed in 2007, with anticipated construction to be completed by 2010.

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Figure 3. Aerated lagoon pilot program in Rae, Northwest Territories. Independent aerated lagoon research by Environment Canada is also underway in the community of Rae, Northwest Territories. The research is focusing on the application of submerged and surface aeration systems, and the performance of these systems during the winter months.

WCWWA 2007 Conference & Trade Show October 23 – 26, 2007

Edmonton, Alberta

THE SOCIAL CONTEXT OF WASTEWATER MANAGEMENT IN REMOTE COMMUNITIES Ken Johnson, M.A.Sc., MCIP, P.Eng. Earth Tech Canada Abstract The development and sustaining of infrastructure in remote communities has always been influenced by a variety of factors. Over the past decade, the complexity of these factors has increased substantially with changes to the available financial resources, the administrative structures, the operational responsibilities, and the regulatory environments. Many of these changes have increased the overall complexity of infrastructure development, and sustainability in remote communities, particularly at the community level. Many communities are finding the demands of these complexities to be well beyond their financial and administrative resources, and as a consequence are placing themselves in very undesirable situations with regard to community funding and regulatory compliance. The challenges associated with wastewater management in remote communities occur in the areas of science, applied science, and social science. The science of wastewater management, particularly northern communities, remains incomplete, and consequently the regulatory frameworks are not realistic. The applied science or "engineering" of wastewater systems in remote communities should follow the key principles of appropriate technology, community context, incremental improvement. The social science associated with wastewater management in remote communities presents a multitude challenges which include, administrative, financial, and human resources. The ecosystems of the remote regions of Canada are unique and fragile, and must be protected. However, to date, the protective measures for these ecosystems have not been developed or implemented based upon the necessary northern science, applied science, and social science information. Introduction

On a political scale the remote areas of Canada constitute as much as 45% of Canada's land mass, including the regions of the Yukon, Northwest Territories, Nunavut, Nunavik (northern Quebec), and Nunatsiavut (northern Labradour) are included (see Figure 1). By contrast this vast region is populated by a mere 100,000 people occupying 90 communities. Which is an average Figure 1. Remote areas of Canada


Edmonton, Alberta

Figure 2. Defining remote areas by temperature – arctic region is defined by 10C isotherm. population of 1100 per community. In fact the communities of Whitehorse (24,000), Yellowknife (19,000) and Iqaluit (7,000) account for about half of the population making the average population for realistically less than 600 people per community. The remote areas of Canada, and the world are most often defined by temperature, as well as geography. In a North American context, all of Canada, with the exception of the west coast, is considered very cold, and in fact, the United States considers the cold region to be the northern portion of the lower 48 states, rather than the state of Alaska (see Figure 2). The subarctic and arctic regions of Canada are considered to be beyond "very cold". The scientific approach defines the Arctic as the area where average temperature for the warmest month of the year (July) is below 10°C (50°F). This macro scale for remote areas is very different from the micro scale that most remotes communities must function within. The limits of remote communities are often defined by the all weather road system that provides access to facilities such as the airport, the water source or the waste management area (see Figure 3). The interactions between these built infrastructure features of remote communities have positive and negative interactions within themselves, as well as the built features associated with human habitation. The development and sustaining of this infrastructure in remote communities has always been influenced by a variety of technical, financial, administrative, operational and regulatory factors. Over the past 10 years the complexity of these factors has increased substantially with changes to the available financial resources, the administrative structures, the operational responsibilities, and the regulatory environments.


Edmonton, Alberta

Many of these changes have increased the overall complexity of infrastructure development, and sustainability in remote communities, particularly at the community level. Many communities are finding the demands of these complexities to be well beyond their financial and administrative resources, and as a consequence are placing themselves in very undesirable situations with regard to community funding and regulatory compliance.

Figure 3. The opportunities and constraints of remote communities

The challenges associated with wastewater management in remote communities occur in the areas of science, applied science, and social science. Science of Wastewater Management The science of modern wastewater treatment systems may be described by a number of unit processes. Each process provides an increasingly higher quality of sewage effluent applying various physical, chemical and biological actions. The unit processes include: • preliminary treatment • primary treatment • secondary treatment • tertiary treatment • disinfection • residuals management. Preliminary treatment is a physical process which may be described in the exaggerated, but very simple terms of coarse screening of the sewage influent to remove “two by fours” and


Edmonton, Alberta

“bicycles.” This exaggeration has occasionally been known to be true, but in a generally expected scenario, the preliminary treatment would remove large objects such as rags or toys. Preliminary treatment may also include such processes as communition, flow measuring, and pumping. Primary treatment is a physical process of suspended solids reduction by either sedimentation or fine screening. The sedimentation process uses gravity in a quiescent basin to settle out the solids, or a fine screen to block passage of solids. The solids, either settled or screened, are removed and processed further as part of the residuals management. Secondary treatment is a biological process of enhanced biodegradation of sewage to reduce the biodegradable material within the sewage. The enhanced conditions for biodegradation include increased availability of oxygen, and an increased number of organisms in the treatment basin. The organisms within the basins may be either suspended in the sewage or attached to a fixed media. Tertiary treatment may be either a chemical or biological process of phosphorus removal, ammonia removal, or other enhancement to remove sewage constituents such as solids or biodegradable material. The removal of any remaining pathogenic organisms in a sewage effluent is the primary purpose of disinfection. The common processes used in disinfection are chlorination, ultraviolet radiation, and ozonation. These methods of disinfection operate on the principles of either direct oxidation of the pathogenic organisms (chlorination or ozonation) or mutation of the organism to kill it (ultraviolet radiation). Residuals management involves a biomass reduction and disposal. The first stage in residuals management is to condition or stabilize the biomass by further biodegradation or digestion employing either an aerobic process (air supplied) or an anaerobic process (no air supplied). The second stage is to reduce its volume by removing the liquid from the biomass by either a physical process or a drying process. The stabilized biomass may also be disposed of directly by application to agricultural land, if it is available. Biodegradation, in addition to sedimentation for solids reduction, is a fundamental process for any wastewater treatment process beyond primary treatment, and is an essential process to produce effluent quality appropriate to minimizing public health and environmental impacts. Biodegradation is, however, significantly reduced by cold temperatures, which is an important factor for the performance of lagoon systems. Fortunately, there are bacterial called Psychrophiles, which are cold-loving, and have optimal temperature for growth at about 15°C or lower, and a maximum temperature for growth at about 20°C, and a minimal temperature for growth at 0°C. In the summer months the warmth and sunlight promote the greatest biodegradation activity in lagoon sewage treatment systems, and the systems must be operated accordingly. The general operating scenario for lagoons in cold regions is a 365 day retention followed by an annual decant. During the winter months with the absence heat and sunlight, the primary process for sewage treatment in lagoons is sedimentation. Sedimentation is also influenced by the cold. Settlement


Edmonton, Alberta

velocity depends on the viscosity of the water it; increased water viscosity implies a slowing of the settling process by a factor of 1.75 for water at 1 C compared to water at 20 C. The science of wastewater management (treatment and disposal) in remotes areas, particularly northern regions, remains incomplete, and consequently the regulatory frameworks are not generally realistic. For example, the practice of just wastewater sampling has inherent problems in the north from the seemingly simple process of getting a water sample to "the lab", to the inability to represent a source environment in a laboratory conditions. Applied Science of Wastewater Management Applied science is the process of taking the science and applying it to specific applications. Thinking outside the “box” is necessary for applied science in remote communities in response to the challenges of extreme cold, very limited access, extraordinary costs, and scant resources. These are a few of the “routine” challenges that engineers, as well as suppliers, contractors must face in designing and constructing wastewater treatment facilities for remote areas. The applied science or "engineering" of wastewater systems in remote communities should follow the key principles of appropriate technology, community context, incremental improvement. These principles have been applied inconsistently to projects in remote communities, and consequently a significant number of projects are not meeting the performance expectations of the communities, and the regulatory authorities. Appropriate technology suggests that whatever process is being applied for wastewater treatment must consider the biophysical context of the project site, which includes location, climate, landforms, and possibly the native vegetation. Cold weather and distance are the two major factors in the consideration of appropriate technology. Although engineering designs may take into account measures to prevent wastewater facilities from freezing, it is also prudent to design the means to “thaw” a facility in the event it does freeze; in fact it may be appropriate to state that it is not a matter of if the facility freezes, but when it freezes. Distance is the second factor influencing appropriate technology. Remote communities, by definition, are located at a great distance from what would be considered the “normal” amenities available to a community. Consequently, the resources available for routine operation, and maintenance may not be available at the facility site, and may be not be available for days or more,and may cost extraordinary amounts of money to mobilize. Appropriate technology for wastewater treatment in remote locations may in fact make use of the extensive cold and limited warmth. One particular application is the concentration of sewage biosolids through the freeze-thaw process, and subsequent composting through the limited summer months. This process is just beginning to be applied in the community of Iqaluit, Nunavut.


Edmonton, Alberta

The community context of a wastewater treatment process has some overlap with the biophysical context of “appropriate technology”, but it is specific to the built environment of a community. A remote community of 100 people has a very different “community” in comparison to a remote community of 500 people. One would expect that the smaller community would have significantly less human resources for the project implementation as well as the operation and maintenance of any wastewater facility. The smaller community would also have less resources for the construction of a wastewater facility. Incremental improvement to wastewater treatment is simply a remote context of the phrase that “Rome was not built in a day”. Project planning is an inherent part of any facility implementation, and in a remote context it is has been recognized that at least a 5 year cycle from planning through to project completion is needed. Year one of the cycle occupies consultation with the community. Many remote communities are aboriginal and consequently may a different cultural perspective on wastewater treatment. Efforts to consult and education communities on the benefits to wastewater treatment are sometimes difficult, but the return on this benefit is significant. Year two of the cycle occupies the technical activity of “engineering” the facility along with continuing community consultation. Years three and four occupy construction, which has a limited window of the year because of the material supply, and cold weather. Year five occupies the critical post construction period where the facility becomes operational; this period may in fact “make or break” the project because the community must take ownership of the functional, as well as the physical attributes of the project. The other benefits of incremental improvements apply to the financial planning and community employment. A multi-year implemental allows the community to reduce the cash flow requirements, and provide longer term employment opportunities for the residents of the community. Social Science of Wastewater Management The science and applied science of wastewater treatment are subjects that need more attention, but attention has been given to these important factors over the past several decades. The social science of wastewater management in remote communities has, however, received much less attention. Even the term “social science” may not be a particularly all encompassing phase to apply to “all of the other stuff” associated with wastewater management in remotes communities, but it is a start. The social science associated with wastewater management in remote communities presents a multitude of challenges which include, administrative, financial, and human resources. Any remote community, regardless of size, has the need for a fully funded, fully staffed, and fully trained community administration; however, this is seldom the case. The administrative challenges include multiple levels of government; limited resources; and changing rules. The multiple levels of government in remote communities may include several levels of local representing the aboriginal community, as well as the non-aboriginal community;


Edmonton, Alberta

the territorial government, as well as the land claim by the aboriginal community; and the federal government, which may have several departments working independently to represent their own mandates. In some communities the various levels of government may number 6 or more. The resources available to communities have been a dynamic environment for remote communities over the past several decades. The “devolution” of responsibilities has been ongoing in response to demands for autonomy from some communities, as well as the downsizing of territorial governments. The devolution process has had varying degrees of success. The latest chapter in the Northwest Territories is the so-called “New Deal” which was implemented in 2007, and provides a block funding to all communities. Some communities are “running” with the opportunity and other communities are overwhelmed. The “New Deal” is a good example of the changing rules that remote communities must cope with. In spite of the best conceived and comprehensive “roll out” possible, the “New Deal” will fail in some communities, as this change in the rules, along with other changes associated with many other administrative aspects of the community, are beyond the community’s capacity. The financial challenges include financial management; capital funding; and operation and maintenance funding. Financial management is a challenge for any community, and represent a continuing challenge for many remote communities. Every remote community has a community budget that is proportionately larger than what would normally be expected in a southern geographic context, and the financial management of this budget requires skill and training that many communities do not possess. Funds for capital, and operation and maintenance from the senior governments have diminished significantly over the past decade, and communities are being encourage to be more self sufficient for financial resources. The human resources challenges include hiring staff; training staff; and retaining staff. Human resources may, in fact, be the most challenging aspect of the social science of wastewater management. People represent a very dynamic environment, which has been plagued with a chronic lack of resources for hiring, training, and retaining. An eye opening example of the financial challenges faced by remote communities is presented with the operation and maintenance costs for water and sewer in the remote communities of Whati, in the Northwest Territories, and Grise Fiord in the Nunavut Territory; Grise Fiord is the northern most community in Canada.


Edmonton, Alberta

Figure 4. Location of Whati, NWT, and Grise Fiord, Nunavut Table 1. Whati, NWT Operation and Maintenance costs Year Water$ Sewer $ Total$ 2001 167,800 71,900 239,700 2002 184,600 79,100 263,700 $580 per capita per year in 2002 or 2.3 cents per litre for water and sewer Water use: 11.5 million litres per year or 70 litres per capita per day Table 2. Grise Fiord, Nunavut Operation and Maintenance costs Year Water $ Sewer $ Total $ 2001 234,391 100,200 334,591 2002 255,959 109,696 365,655 $2,240 per capita per year in 2002 or 6.4 cents per litre for water and sewer Water use - 5,678,500 litres per year or 95 litres per capita per day In comparison the cost of water is 0.12 cents per litre in Edmonton. Conclusions Lagoons have been the sewage treatment process of choice for most remote communities because of the cost effectiveness, simplicity of operation, and abundance of space available to most communities. This situation has been changing over the past decade as regulators have lobbied Water Boards, and pressured communities to improve effluent quality by applying conventional “southern” mechanical technologies. This evolution has exhibited mixed results with “new” mechanical systems operating in the northern communities of Fort Simpson, Rankin Inlet, Iqaluit and Pangnirtung. Although it may be said that these systems are generally operating in compliance with the water licence parameters, the communities are faced with a legacy of sustaining these processes with limited


Edmonton, Alberta

financial and human resources. New challenges are emerging for these communities because of the demands for managing the significant biosolids waste stream produced by the waste treatment process. The ecosystems of the remote regions of Canada are unique and fragile, and must be protected, hence the need for wastewater treatment. Public health must also be protected, and wastewater treatment must serve this purpose as well. However, to date, the protective measures for these ecosystems and public health have not been developed or implemented based upon the necessary science, applied science, and social science information.

CSCE 2007 Annual General Meeting & Conference Congrès annuel et assemblée générale annuelle SCGC 2007

Yellowknife, Northwest Territories / Yellowknife, Territoires du nord-ouest June 6-9, 2007 / 6 au 9 juin 2007

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Engineered Improvements to Sewage Treatment System in Cambridge Bay, Nunavut

Ken Johnson and Michelle Yu, Earth Tech Canada Navjit Sidhu, Government of Nunavut

Abstract

The existing sewage facility serving the community of Cambridge Bay is a typical northern lagoon system developed through a system of natural ponds, and refined with limited containment and control structures. All of the improvements to the pond system were essentially not engineered and as a result, the system has been a continuing source of concern for both the community and the regulatory organizations.

A planning study was undertaken to try and identify a number of new locations for the community to relocate the sewage lagoon system, however, none of the proposed sites have presented a satisfactory alternative in terms of community, environmental, or financial impact. As an alternative to the development of a new site, “engineered” improvements to the existing site have been developed.

The engineering of improvements to a natural system originates from the analysis of the system process and system capacity, and the identification of elements that may enhance the process and capacity. In the case of the Cambridge Bay facility, the existing pond system has the inherent facilitative process to treat sewage, and may be redeveloped to provide the appropriate long term capacity.

A series of site investigations including wastewater sampling, and a topographic survey provided the basis for making these conclusions. The next step in the process is the engineering and implementation of the necessary improvements. A key to the engineering is the identification of appropriate materials and methods to carry out these improvements. The use of available soil materials from the community provides the basis for implementing the improvements in an economical and incremental manner.

1. Introduction

A series of potential waste management areas for the community of Cambridge Bay were identified based upon the community’s interest in relocating the exiting lagoon facility. The planning analysis of the potential new sites included a "proximity" analysis of human activities and natural features; an analysis of potential road access to each site; an estimate of capital and operation and maintenance costs; and general site development configurations for the sites.

Water sampling of the existing waste management facilities was also carried out to provide additional information to the existing sampling studies. A report suggested that the lagoon system of treatment is working satisfactorily to reduce the concentration of sewage contaminants to the acceptable level prior to discharge into the environment. Based upon the input from the community, and the direction provided by the Government of Nunavut, preliminary engineering for redevelopment of the existing sewage treatment

proceeded. It is anticipated that the preliminary engineering information will provide a basis for a submission to the Nunavut Water Board for approval of the improvements. Community stakeholder consultations on the redevelopment of the existing site will also continue.

In support of advancing the redevelopment of the existing waste management sites, a topographical survey, and a geotechnical investigation of the sites were undertaken. The topographic survey generated accurate contour information for the lagoon pond areas, and the discharge stream; the geotechnical investigation provided information on the soil conditions around the sites, and information on the soil materials around the community that may be used for the construction of any redevelopment work.

2. Community Information

The community of Cambridge Bay is the largest community in the Kitikmeot Region of Nunavut, and is geographically situated on the Dease Strait between the Queen Maud Gulf and the Coronation Gulf in the North West Passage. It is located on 69° 07' N latitude and 105°03' W longitude, and it is approximately 960 air km north east of Yellowknife. It is one of the most westerly communities of Nunavut, with a population of 1,609 in 2006. Recent population figures for the community point to higher than normal growth.

The Hamlet of Cambridge Bay is situated in an area of sags and swells, dry debris-strewn knolls, and moist depressions, with limited vegetation. The climate can be characterized by long cold winters and short cool summers, and the daily average temperature is -14.4°C. The average total annual precipitation is 13.9 cm, consisting of 82.1 cm of snowfall and 7.0 cm of rainfall. The July mean high is 12.3°C, and the mean low is 4.6°C. The January mean high is -29.3°C, and mean low is -36.3°C.

According to the 2004 Hamlet of Cambridge Bay Community Economic Development Plan, Cambridge Bay is a very progressive community with unlimited potential. It is expected that, being the hub of Kitikmeot Region, the community will experience a substantial economic growth in future years. The proposed Bathurst Inlet port, road, health center projects, and mining ventures, will increase social and tourism activities in the community, and will also place a significant burden on the existing infrastructure.

3. Existing Services

The water use and waste disposal in the Hamlet of Cambridge Bay is regulated by a Type B Water License. The present source of the community's potable water source is Water Lake located approximately 3 km north of the community (see Figure 1). Water trucks are used to distribute water to houses in the community; water uptake from Water Lake totals approximately 20 truckloads per day (12000 L per truckload). The current water consumption is approximately 87,600 m3/year, although the current water license allows for the removal of 70,000 m3 of water from Water Lake annually.

Sewage is collected from the community by sewage trucks, and discharged into a sewage lagoon system, which is used to treat wastewater for the community. Currently, on average 16 truckloads (12,000 L per truckload) of sewage are discharged into the lagoon each day. The existing lagoon is located approximately 1.5 km north east of the community, and has been in use for over thirty years. The system consists of several natural ponds connects in series, with a volume of approximately 72,000 m3 based on the normal operating level in the lagoon ponds.

The sewage is discharged into the first pond of the lagoon at truck discharge site. The treated sewage the lagoon is ultimately channelled into Cambridge Bay. Currently, there is no discharge control structure in the lagoon, therefore, sewage effluent from the lagoon is discharged continuously. The lagoon is annually flooded due to the spring runoff from the adjacent catchment areas into the lagoon.

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Figure 1. Cambridge Bay water and sewer facility locations.

There are several issues of concern with the system. The main concern is the influence of large spring runoff flows into the lagoon, which reduce the storage and treatment capacity of the lagoon due to the magnitude of the flows. The other concerns with the system include the ultimate treatment capacity of the lagoon, and the discharge point of the lagoon, which is within 450 metres of the community.

The results of limited effluent sampling suggest that the concentration of all the effluent discharge parameters (contaminants) collected from sampling points were below the respective Municipal Waste Water Effluent Guidelines. The overall sampling results suggested that the lagoon system of treatment is working satisfactorily to reduce the concentration of sewage contaminants to the acceptable level prior to discharge into the environment (Cambridge Bay).

4. Sewage Characteristics and Quantity

Wastewater generated in Cambridge Bay is domestic in source and characteristics. The wastewater quality from the community may be considered to be a "high strength" waste because of the use of a

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trucked sewage and water system. The "high strength" condition is typical for trucked sewage and water systems due to the low water usage, which translates into low dilution of the raw sewage.

The Hamlet of Cambridge Bay's current water license stipulates the effluent requirement. The current water license came in effect on September 1, 2002 and expires on August 31, 2007. The conditions applying to waste disposal are stipulated in Part D of the license and presented in Table 1.

Table 1. Effluent Quality Standards

Parameter Maximum Average Concentration Faecal Coliforms 1 x 106CFU/dl BOD5 100 mg/L Total Suspended Solids 120 mg/L Oil and grease No visible sheen pH Between 6 and 9

Based upon population projection by the Nunavut Bureau of Statistics, the generation of sewage waste is estimated for the next 20 years (starting from 2006). Table 2 presents the summary of sewage generation in the next 20 years.

Table 2. Estimated Sewage Waste Volume Generation for the Hamlet of Cambridge Bay, 2007 to 2025

Year Population Daily Flow Yearly Flow

m3/day m3/year

2007 1,642 230 83,906 2010 1,752 356 89,527 2015 1,939 271 99,083 2020 2,137 299 109,201 2025 2,360 330 120,572

Notes: 1. Population projection data (2020-2025) based on 2% growth rate (determined from GN population

projection data). 2. Population projection data (2020-2025) extrapolated by Earth Tech. 3. Average daily sewage waste generation rate per person is 140 litres.

5. Sewage Lagoon Improvements

The lagoon sample results indicates that the concentration of the effluent discharge parameters is below the concentration required by the water license. The sampling results suggest that the lagoon system of treatment is working satisfactorily to reduce the concentration of sewage contaminants to the acceptable

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level prior to discharge into the environment. The existing lagoon system may still serve the Hamlet as a sewage treatment facility for next 20 years with the improvements that appropriately address all the issues of concern.

Table 3. Sewage Lagoon Design Criteria

Design Treatment Capacity: 120,000 cubic meters per year (20 year horizon) Design Effluent Quality: Faecal Coliforms 1 x 106CFU/dl BOD5 100 mg/L Total Suspended Solids 120 mg/L pH Between 6 and 9 Lagoon Pond Area: 14.8 hectares Average Depth: 0.81 meters Storage Volume: 120,000 cubic meters Freeboard: 1 metre Discharge: Annually Supplemental Treatment: Wetland

The current sewage generation rate is approximately 70,080 cubic meters per year. The existing high water level of the lagoon is approximately 8.85 metres above sea level. On the basis of hydraulic retention time (HRT), the current lagoon may achieve a HRT of approximately 375 days based on the current sewage generation rate. This is based on a rough volume estimate of 72,000 cubic meters for the existing lagoon storage. This HRT achieves the maximum benefit from retention during the limited summer season.

By the year of 2025 the sewage generation rate would be approximately 120,000 cubic meters per year. The HRT would be reduced to approximately 219 days based upon the current capacity. A 219 day HRT may not achieve the maximum benefit from complete sewage retention during the limited summer season (June, July, and August) resulting from solar energy, and biological activity. The lagoon volume may be increased by increasing the high water level. A water level elevation of 9.5 metres will provide a lagoon volume of 119,000 cubic meters, and the HRT will be approximately 360 days. The increased water level of 9.5 metres would be achieved by construction and reinforcement of berms.

5.1 Primary Cell

In order to improve the lagoon performance and to extent the lifetime of the lagoon, a primary cell is proposed at northwest side of the main pond. A submerged berm is proposed to separate primary cell and secondary cell (see Figure 2). The sewage would then be pre-treated, and much of the suspended solids would be settled out within the primary cell before sewage enters the secondary cell. The sludge settled in primary cell could be removed on a period basis.

A truck discharge flume will be located at the west end of the primary cell. The sewage truck will use the discharge flume to deposit raw sewage into the lagoon. There would be a treated lumber wheel stop and bollards at the edge of the pad to prevent the truck from backing into the sewage lagoon. From the truck pad the offload chute consisting of an 800 millimetre diameter nestable culverts will run down the inside slope of the berm to the rip rap area at the bottom of the primary cell.

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Figure 2. Submerged solids retention berm

5.2 Decant System

A mobile decant system will be located at the opposite end of the lagoon to the truck discharge flume. The lagoon will be annually discharged by pumping effluent into the receiving environment from the lagoon using a powered pump. Given the maximum annual sewage volume of 120,000 m3, a mobile decant facility which includes a diesel engine driven self priming pump is proposed to decant the lagoon annually over a period of three weeks.

5.3 Spillway

A spillway is proposed in order to control the lagoon high water level in the event of an extreme runoff situation. The spillway route would be same to the discharge route as the existing lagoon system. Any water about high water level (9.5 metres) would overflow through the spillway on the proposed retention berm.

5.4 Supplemental Wetland Treatment

An engineered wetland is proposed to further treat the effluent from the lagoon system. Water quality improvement is improved through a variety of natural processes that occur in wetlands. The technology of seasonal discharge from a lagoon to wetlands has been demonstrated to provide significant sewage treatment capabilities. Using natural filtration, sedimentation, and physical or chemical immobilization, the soil and plants of wetland systems effectively absorb and retain suspended solids, carbonaceous and nitrogenous components of BOD, nutrients (including phosphorus), pathogenic organisms including coliforms, and other pollutants. Although there is a limited wetland downstream of the existing lagoon, the performance of this wetland may be greatly enhanced by constructing an engineered wetland to optimize the flow and vegetation.

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Figure 3. Lagoon Improvements and discharge.

5.5 Discharge Point

The effluent will be diverted around an existing the bulky metal dump site with a pumped decant system. The effluent would enter the engineered wetland before crossing the existing road to the south. Twin 500 mm culverts running under the road will be required. From this point, the effluent will flow into the bay. The proposed discharge point would 420 metres east of the existing discharge point, and 675 metres east of the community. This changed point would avoid the conflict with the discharge proximity to the community.

5.6 Runoff Diversion

One of the major concerns regarding the existing lagoon is the spring runoff flows into the lagoon, which influences the performance and capacity of the lagoon. Consideration of this concern suggests that runoff diversion berms would be required. The proposed runoff diversion berms are identified based on the watershed contours. The runoff diversion berms would divert most of the runoff around the lagoon either to the east or west.

5.7 Capital Cost The cost of a new lagoon site would be more than $3.7 million. In comparison, it would cost approximately $1.8 million (Class C estimate) to improve the existing lagoon.

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6. Conclusions and Recommendations

The existing lagoon system appears to be functioning to reduce the concentration of sewage contaminants to the acceptable level prior to discharge into the environment. Therefore, it is feasible to use the existing lagoon site with improvements regarding the current concerns. Redevelopment of the existing site is the more cost effective option if all the concerns regarding to the existing lagoon site configuration and operation are addressed properly.

The improvements to the existing lagoon system can be planned and constructed in an incremental fashion according to the priority of each component of the improvement. This will give the community a funding and manpower flexibility regarding the ultimate development of the lagoon improvements.

The recommended construction priority would be as follows:

1. Improve flow under the road along the existing discharge channel by replacing culverts. 2. Construct runoff diversion berms to divert runoff around from the lagoon. 3. Construct retention berms and submerged berms related to capacity increase. 4. Purchase decanting equipment. 5. Extend access road and build the truck discharge flume. 6. Construct the engineered wetland and the new discharge point.

7. References

Earth Tech, February 2006, Hamlet of Cambridge Bay Integrated Sewage and Solid Waste Facilities Design – Progress Report No. 1 (Research Report).

Earth Tech, July 2006, Hamlet of Cambridge Bay Sewage and Solid Waste Facilities – Planning Report.

Earth Tech, August, 2006, Cambridge Bay Waste Facility Improvements Sewage Analysis – Summary Report.

Earth Tech, April, 2007, Cambridge Bay Waste Facility Improvements, Preliminary Engineering Report for Redevelopment of Existing Sewage Lagoon.

Inuvialuit Environmental and Geotechnical, October 2005, Cambridge Bay Municipal Sewage Lagoon and Waste Facilities Assessment (GN Project No. 04-4807).

Municipal and Community Affairs, GNWT, April 2003, Guidelines for the Planning, Design, Operation, and Maintenance of Sewage Lagoons in the Northwest Territories.

Northwest Territories Water Board, 1992, Guidelines for the Discharge of Treated Municipal Wastewater in the Northwest Territories.

Nunavut Bureau of Statistics http://www.stats.gov.nu.ca/statistics%20documents/pop_projections_by_comm.pdf

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http://www.stats.gov.nu.ca/statistics documents/pop_projections_by_comm.pdf

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Application Of Large Scale At-Grade Sewage Treatment And Disposal In Fort Good Hope, NWT Kenneth R. Johnson1, Amir Agha2, and Mukesh Mathrani1 1 Earth Tech Canada Inc., Edmonton, Alberta, Canada 2 Department of Municipal and Community Affairs, GNWT, Norman Wells, NWT, Canada Abstract: The Charter Community of Fort Good Hope, NWT continues to use an exfiltration trench for disposal and treatment of domestic wastewater. This community of 550 people is located just south of the Arctic Circle, in the continuous permafrost region of the north. Sewage volumes are expected to increase with the community population over the next twenty years, and the existing exfiltration lagoon configuration will ultimately not have the capacity for the increasing volume. A study was completed to evaluate the capacity and efficiency of the existing system, and the opportunity to maintain, or improve this unusual application of at-grade sewage treatment and disposal. Based upon the available site information and the performance of the existing system, it was concluded that the process has the hydraulic and treatment capacity to meet the community’s demand and maintain regulatory compliance. 1. INTRODUCTION 1.1 Community Environment The Charter Community of Fort Good Hope (K'asho Got'ine) is a Dene community in the Sahtu Region of the Northwest Territories, located at 66º 15' N and 128º 3' W. The community lies on a peninsula at the confluence of Jackfish Creek, and the east bank of the Mackenzie River (See Figure 1). The town site is 27 kilometres south of the Arctic Circle, about 805 kilometres northwest by air from Yellowknife, and 145 kilometres northwest of Norman Wells. The terrain surrounding Fort Good Hope generally consists of muskeg, swamp, and areas covered with trees ranging in size from stunted growth up to 12 metres in height. However, several significant glacial and fluvial deposits surround the community, and provide one of the few nearby community deposits of concrete gravel in the NWT. Fort Good Hope is situated within the continuous permafrost zone; the active layer penetrates 0.5 to 1.2 metres below the ground surface in the summer. The community receives a total annual precipitation of 267 millimetres, with an average of 150 millimetres of rain and 132 centimetres of snow each year. Mean high and low temperatures vary between 22.6 and 9.9ºC in July and between -27.5 and -35.0ºC in January. Prevailing winds are from the east and average 9.5 km/h annually. Sewage collection in Fort Good Hope employs sewage pumpout tanks. Pumped out sewage is trucked to an exfiltration trench located at the waste disposal facility about 3.5 kilometres north of the community. The estimated monthly volume of pumpout sewage discharged to the exfiltration trench is 1.6 million litres, which is approximately 140 litres per capita per day (550 estimated population). The exfiltration trench is

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Calgary, Alberta, Canada May 23-26, 2006 / 23-26 Mai 2006

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approximately 98 metres long, 12 metre wide and up to 3 metres deep; the approximate working volume of the trench is 1500 cubic metres.

Figure 1. Fort Good Hope site plan.

1.2 Existing Sewage Exfiltration Area The 9.0 hectare waste disposal site (240 metres wide by 375 metres long), and is part of a 90 hectare glacial outwash plain located between the townsite and the Hare Indian River. The average depth of the glacial outwash plain is approximately 10 metres, and the deposit contains approximately 9 million cubic metres of poorly graded gravel. The glacial out wash place is one of a series of granular deposits around Fort Good Hope. The deposit is comprised of medium grained gravel that ranges in soil classification from "poorly graded gravel, gravel-sand mix, little or no fines" to "poorly graded sand, gravelly sand, little or no fines". The gradation of the gravel in the area ranges between 20% and 95% sand, 2% and 7 9% gravel, and 1% to 14% silt-clay. The high permeability of the gravel results in good drainage within the area, and the water table in this area appears to be deeper than 15 metres, while the depth of the sewage trench is up to 3 metres deep.

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The exfiltration trench does not have any "controlled" discharge system. Upon discharge into the trench, the sewage flows by gravity to fill the entire trench to a level surface. The sewage then "exfiltrates" from the bottom and sides of the trench into the glacial outwash plain deposit, and then "percolates" downward through the deposit (unsaturated flow) until the groundwater table, and then flows into the groundwater (saturated flow). The exfiltration trench in the glacial outwash plain is situated at an elevation of approximately 230 metres, which is about 225 metres above the Mackenzie River elevation of 75 metres (See Figure 2). The exfiltration trench is about 1200 metres from the Mackenzie River. The exfiltration trench and the outwash plain are both oriented parallel to the Mackenzie River. 2. SYSTEM OPERATION AND PERFORMANCE The Water Licence issued to the Charter Community of Fort Good Hope by the Sahtu Land and Water Board refers to an appended "Surveillance Network Program" (SNP) when outlining the effluent quality standards required for compliance of the sewage trench seepage. However, the SNP information does not include any specific discharge criteria; historically, many northern communities have been required to meet the discharge parameters of effluent 120 mg/L for Biological Oxygen Demand (BOD5), and 180 mg/L for effluent Total Suspended Solids (TSS). The exfiltration trench treats the sewage in a much different way than the more conventional sewage retention lagoon. A retention lagoon uses the elements of nature at the earth's surface including heat, sunlight, wind and surface vegetation. An exfiltration trench uses the elements of nature in the available soil "matrix", and the processes of biodegradation, filtration, adsorption and absorption to remove the contaminants in sewage. The trench is currently capable of accommodating the volume of sewage produced by Fort Good Hope based upon the community observations; in fact, the sewage percolates quickly into the gravel. However, the community has observed that the level of liquid in the trench has been steadily increasing with time, which is an anticipated part of the performance of an exfiltration process. Sewage solids accumulate with time over the bottom of the trench, and reduce the permeability of the soil; at the same time, this reduction in permeability also reduces the flow through the soil, and enhances the processes removing the contaminants in the soil. Sampling was performed in the months of June to August 2001 on the seepage that is believed to originate from the sewage exfiltration trench. The samples were taken from a stream of water between the exfiltration trench and the Mackenzie River, with the assumption that the groundwater flows toward the Mackenzie River. The results of the sampling analyses indicated that the BOD5 ranged from less than 2 to 7 mg/L, and that the TSS ranged from less than 3 to 6 mg/L. This limited sample data indicates a very high quality of effluent treatment within the soil matrix beneath the exfiltration trench; this effluent quality may be equated to a tertiary level of treatment. In comparison the commonly used water effluent parameters in northern community water licenses, as discussed previously, the BOD5 measured at Fort Good Hope is well below the target of 120 mg/L and the TSS analyzed was well below 180 mg/L.

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Figure 2. Fort Good Hope site plan and profile.

3. WASTE GENERATION AND SYSTEM CAPACITIES The production of sewage in Fort Good Hope is expected to increase substantially in the next 20 years. Statistics from the Government of the Northwest Territories projects that aboriginal populations may increase at a rate of 0.5 % annually. Based on the estimated population of Fort Good Hope in the year 2003 of 550, and a water consumption volume of 140 litres (0.140 m3) per person per day (April 2004), an estimated 25,000 m3 of domestic sewage will be produced annually by the year 2015, and 32,000 m3 by the year 2025. The existing exfiltration trench has never overflowed, however, the community is concerned that the trench is filling up higher than it ever has before and could overflow in the near future. The ultimate capacity of the existing system is impossible to calculate given the many factors that influence the hydraulic capacity

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of the trench. These factors include the granular material in the base and side of the trench, the solids accumulation in the base and sides of the trench, the influence of seasonal frost in reducing the soil permeability, and the influence of permafrost on the soil permeability. The best indication of system capacity are site observations on the rate of exfiltration from the trench; this activity is essentially a "percolation test" of the soil. From a design perspective, the general operational range or hydraulic loading for a "rapid infiltration" system such as this is 6 to 125 metres per year. The estimated loading rate of the Fort Good Hope exfiltration trench is about 20 metres per year based upon sewage generation of 50 m3 per day, and an estimated infiltration surface of 900 m2. 4. SOIL EXFILTRATION TREATMENT PROCESSES Soil exfiltration of wastewater uses the elements of nature in the available soil "matrix", and the processes of biodegradation, filtration, adsorption and absorption to remove the contaminants in sewage. A soil matrix approximately 30 centimetres (12 inches) thick may adequately remove the contaminants in sewage, if it is appropriately engineered and operated. All soils have a natural capability to "filter" contaminants because of the inherent biology, and chemical activities that occur in soil. A soil exfiltration system may produce a tertiary quality effluent if engineered and operated properly. The anticipated effluent characteristics are presented in Table 1.

Table 1. Anticipated Effluent Characteristics

Effluent Parameter BOD5 < 5 mg/L TSS < 2 mg/L Total Nitrogen < 10 mg/L Total Phosphorous < 1 mg/L Fecal Coliforms < 10 FC/100 mL

The wastewater contaminants that have been most widely studied for removal by a soil matrix are coliforms, biodegradable material (measured by BOD5), nitrogen and phosphorous. Coliforms and other pathogen organisms are removed by physical straining, and "die off" as a result of the harsh environment of the soil. This harsh environment includes the temperature, the absence of any nutrients for the coliforms, and the natural antibiotics in the soil. Biodegradable material is removed by the bacterial metabolism with the "living filter" of the soil – the natural or introduced bacterial literally consume the biodegradable material as it flows through the soil. Nitrogen compounds, primarily in the form of ammonia, undergo a series of reactions with a soil profile resulting in the transformation, and potentially the complete removal of nitrogen from the soil or the storage of nitrogen in the soil. From a biochemical and chemical perspective, the nitrogen removal occurs as a result of nitrification, denitrification, volatization or chemodenitrification. Within a gravel soil profile the nitrogen transformation may be limited to nitrification and the formation of nitrates, which may occur to an extent of 80% within a 1 metre depth of soil. Phosphorous compounds are "retained" by soil through either a chemical reaction or an adsorption reaction. In the application of these "processes" in the natural environment, there is a recognition that the process occurs at different rates in "unsaturated" and "saturated" zones in the soil (See Figure 3). The saturated and unsaturated zones are defined by the position of the groundwater table – the unsaturated zone is the region above the groundwater table and the saturated zone is in the region below the groundwater table. The efficiency and rate of the various biochemical and chemical processes is substantially higher in the unsaturated zone, and this fact is recognized in most regulations governing the use of soil for effluent disposal, where a minimum unsaturated depth of soil is required for complete treatment to occur. These

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depths vary from as little as 30 centimetres for well graded sand to about 1 metre for other soil types. However, the saturated zone still has "treatment" capabilities that are significant. Temperature may have a significant influence on the biochemical and chemical processes within the soil; however, biochemical and chemical process still occur at cold temperatures, but at slower rates. In practical terms, slower rates demand either a lower sewage application on a given soil profile, or an increased soil profile to achieve the same level of treatment.

Figure 3. Soil exfiltration treatment processes.

5. CONCLUSIONS AND RECOMMENDATIONS The existing sewage exfiltration trench in Charter Community Fort Good Hope is an appropriate sewage treatment technology for this community based upon the technical process information, and the limited performance data. The process is capable of providing a very high quality sewage effluent before discharge into the receiving environment. A number of improvements may be made to the existing process, both in the construction and the operation and maintenance. The capital improvements include:

1. Constructing an erosion protected discharge into the trench to reduce the accumulation of rocks and sediment in the trench.

2. Constructing an engineered discharge structure beside the trench.

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3. Constructing a perimeter fence to isolate the trench. 4. Constructing a water level monitoring post in the trench.

The operation and maintenance improvements include:

1. Undertaking regular sampling of the representative discharge from the trench at the base of the granular deposit.

2. Undertaking regular monitoring of the water level in the trench. 3. Undertaking periodic “resting” of the trenches (summer only), where a second trench is needed to

meet the treatment capacity for the community. The capacity limitation of the existing trench is difficult to determine, therefore the regular monitoring of the water level will provide the necessary data to determine the timeframe for increasing the capacity of the sewage exfiltration system. When a second trench is required, it should be constructed beyond the existing trench, and not parallel to the existing trench, in order to take advantage of additional treatment capacity in the granular deposit. The design criteria for the trench should include a long narrow excavation with a minimum depth of 3 metres in order to minimize the surface area exposed to the atmosphere, and to maximize the heat retention. 6. REFERENCES Dillon Consulting Limited. 2003. Fort Good Hope Water Licence Application. Ferguson Simek Clark. 2000. Draft Report: Engineering and Environmental Services Fort Good Hope – Sewage and Solid Waste Assessment. Ferguson Simek Clark. 2000. Sewage and Solid Waste Management Site Operations and Maintenance Manual. Johnson, Kenneth Robert. 1986. Role of Saturated and Unsaturated Zones in Soil Disposal of Septic Tank Effluent. Johnson, Ken and Wilson, Anne. 1999. Sewage Treatment Systems in Communities and Camps of the Northwest Territories and Nunavut Territory. Proceedings of the 1st Cold Regions Specialty Conference of the Canadian Society for Civil Engineering. K’asho Got’ine Chartered Community Council. 2005. Annual Report for Water. Reed, S.C., Crites, R.W., and Middlebrooks, E.J.1995. Natural Systems for Waste Management and Treatment. Terriplan Consultants Ltd. and Ferguson Simek Clark. 2001. Fort Good Hope Community Plan and Zoning By-Law Background Report. Thurber Engineering Ltd. 1995. Granular Inventory and Management Plan – Community of Fort Good Hope, NWT.

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Figure 1: Trucked Sewage Discharge Iqaluit WWTP Phase 1 in background

Integrated Waste Management in Iqaluit, Nunavut Ken Johnson, P.Eng., Earth Tech Canada Glenn Prosko, P.Eng., Earth Tech Canada Prepared for Consulting Engineers of Award Application, September, 2006 Received Award of Merit, Municipal Engineering Category Background Since the application of modern sewage treatment technologies in the past century, municipal sewage sludge has been an inherent part of overall waste management practices. It was traditionally considered a waste product, and disposed of like any other waste. Ultimately, however, the high nutrient characteristics and pathogens in sewage sludge were identified, and over the past 30 years sewage sludge has been recognized as a waste material that requires specific handling, treatment and disposal practices. Sewage sludge also has beneficial uses which have been covered by government regulations since the early 1990’s. These regulations discourage the disposal of untreated sewage sludge on agriculture lands or in landfills. Most municipalities in Canada recognize that sewage sludge presents treatment and disposal challenges, and that care is needed to protect public health and the environment. In the Canadian north, municipal sewage sludge has been virtually ignored because of the predominance of lagoon wastewater treatment systems. In a lagoon system, sewage sludge essentially becomes part of the lagoon itself as it settles to the bottom. Only when the performance of a lagoon starts to decrease substantially is it deemed necessary to remove sewage sludge. This periodic exercise may occur every 10 to 15 years. The application of mechanical sewage treatment systems in the Northwest Territories and Nunavut, and an increased regulatory scrutiny over the past 15 years have created a demand for sewage sludge handling, treatment, and disposal. Landfilling of sewage sludge is a “tried and true” technology because of its limited requirements for planning, engineering and regulation; however, regulatory demands have been increasing, and sludge management in an engineered context is a necessary part of any new mechanical sewage treatment system. The City of Iqaluit, Nunavut has been working toward the implementation of a secondary sewage treatment system since 1998. This is an ambitious goal for the community considering the inherent challenges to the design, construction and operation of facilities in the harsh arctic environment. After an initial membrane treatment project failed to be commissioned in 2000, the City

Integrated Waste Management in Iqaluit, Nunavut

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Figure 2: Iqaluit WWTP Phase 1

chose to pursue a conventional activated sludge process: the first phase (primary treatment) of this project was commissioned in May 2006; the second phase (secondary treatment) is scheduled for implementation within the next 5 years. Community Characteristics

Iqaluit is the largest community and the capital city of Nunavut, located in the southeast part of the Baffin Island, at 63° 44’ N latitude and 68° 31’ W longitude. Iqaluit is 2300 kilometres east of Yellowknife, and 2800 kilometres northeast of Edmonton. Located at the head of Frobisher Bay, the community was established in 1949 as the community of Frobisher Bay. It became a municipal hamlet in 1971 and the capital city of Nunavut in 1999. The Government of Nunavut population projection for Iqaluit was 5,600 in 2005 and the community is expected to grow to over 8,000 in the year 2020. Approximately 60

percent of the community is presently aboriginal. Land area within the municipal boundary is 52.3 square kilometres. Iqaluit’s location is above the tree line and within the continuous permafrost zone of Canada. The terrain surrounding Iqaluit is “rolling”, and the region generally consists of glacially scoured igneous/metamorphic terrain. The overburden consists of silty-sand, sand, gravel and boulders, which varies in depth up to 18 meters. For 8 months of the year, the average daily temperature in Iqaluit is below freezing. The January high and low mean temperatures are -21.5 °C and -29.7 °C, respectively, and the July high and low mean temperatures are 11.4 °C and 3.7 °C, respectively. Annual precipitation is 43.0 cm, and is made up of 19.2 cm of rainfall and 25.5 cm of snowfall. The community operates both a piped sewage system and a trucked sewage system. The pipe sewage system serves approximately 65 percent of the community, and the remainder of community is served by trucks which pumpout individual tanks in each home. Solid Waste Management Practices The City produces approximately 10,000 cubic meters of compacted waste, which enters the landfill each year, and includes residential, commercial and industrial wastes. Recycling is currently limited to the collection and diversion of aluminum cans. The City’s landfill operation uses the area method, which involves placing waste above grade against a berm, compacting the waste using a wheeled loader, and covering the waste using a mulch material. The waste is covered once per day during the summer and once per week during the winter.


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Figure 3: Iqaluit Landfill

Figure 4: Shredder Operation at Iqaluit Landfill

Raw material on left and finished product on right

City of Iqaluit landfill staff have taken significant steps in attempting to reduce the amount of waste entering the existing operational cell. Shredding the waste was identified as a significant volume reduction measure, as the resulting mulch may be used as a waste cover material. The amount of waste deposited at the City’s landfill which is available for reuse as cover material is approximately 20% of the total annual volume. This waste for reuse consists mainly of select construction debris, furniture, cardboard and plastic. The waste is segregated from the general waste stream and stockpiled in a specific area of the landfill. Limited compaction is then used to prepare the waste material for loading in the 120 hp shredder.

Once these materials have been properly shredded, the material is stockpiled and used for landfill cover, local road building (within landfill), and berm reinforcement during the winter months.


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Figure 6: Sludge from Primary Filter

(Salsnes filtration unit)

Figure 7: Sewage Sludge Trailer

Figure 5: Phase 1 Filtration Systems - Fine Screen and

Primary Filter

Sewage Sludge Composition and Volumes The sewage sludge waste streams from the wastewater treatment plant (WWTP) will have 3 distinct components: the first will be fine screening, the second will be sludge from the primary filter, and the third will be sludge from the waste activated treatment system. The first phase of the WWTP project will incorporate only sludge streams for fine screening and the primary filter. The fine screening is accomplished utilizing screens salvaged from the original un-commissioned construction; the primary sludge is produced form a newly installed Salsnes filter. The Salsnes filter is a relatively new process with its origins in Norway, which applies a moving fabric with a nominal opening size of 300 microns to filter the sewage. The daily mass of screenings and primary sewage sludge produced from a future population of over 8,000 (in the year 2020) is expected to be approximately 1,700 kilogram (a volume of approximately 1.8 to 2.0 cubic meters). With these quantities, the primary sewage sludge trailer would have to be unloaded once every two days. With the current population of 5,600, the sludge trailer is unloaded every two or three days.

Environmental Planning for Sludge Management The potential land base available to the City of Iqaluit is very large at over 50 square kilometers, particularly in comparison to the population base of approximately 6,000 people. However, the potential area for sewage sludge management is very limited by the existing road network. Building any new access road is very expensive, with a capital cost in excess of $500,000 per kilometer in addition to significant operation and maintenance costs.


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Figure 8: Development Setback

Envelope for Waste Management

Figure 10: Three Potential Locations

for Sludge Management Sites.

One of the primary regulations governing the development of any waste management site is a 450 metres setback from residential or commercial developments. Based on the current development limits of the City, a 450 meter setback creates a significant limitation on sludge management. The City of Iqaluit has a comprehensive community plan which stipulates land use designations and identifies existing land uses of interest or concern to future land development. Of particular interest and concern are the open space areas, and a significant number of old waste disposal sites. Applying the environment planning information produced three potential locations for potential sludge disposal locations. Transportation from the WWTP to two of the sites posed a potential concern because the access routes go through the community. Based on the environmental planning exercise, the existing landfill site was recommended for sludge management.

Figure 9: Land Use in and around Iqaluit


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Figure 11: Sewage Sludge

Freeze-Thaw Drying

Process Review for Sludge Treatment and Disposal Conventional municipal sewage treatment uses physical, chemical, and biological processes to separate solids and biological contaminants from municipal wastewater. Solids in the wastewater are removed through primary treatment (primary sludge), and biological contaminants are removed through secondary treatment (secondary sludge). Solids in the sludge are typically processed in a digester system, in which biodegradable materials are “digested” into stable organic matter.

Sewage sludge may be further treated through dewatering, heat drying, alkaline (lime) stabilization, composting, or other processes. Regardless of the treatment technology, there are limited options for end use or ultimate disposal of sewage sludge, especially in a harsh arctic environment. . In Canada, approximately 388,700 dry tonnes of biosolids are produced every year. About 43% of the sewage sludge is applied to land, 47% is incinerated, and 4% is sent to landfill, with the remainder used in land reclamation and other uses. Land application has been increasing in recent years as many municipalities move away from incineration and landfill disposal due to environmental concerns with these processes.

There are a variety of conventional as well as modified, patented, and proprietary sewage sludge management technologies available, and many of these technologies are not necessarily "appropriate" for the City of Iqaluit given the extreme operating conditions inherent the climate and location of the community. A comprehensive process was applied to provide a sewage sludge management plan to the City of Iqaluit. The process involved the following steps:

1. Identifying all available sewage sludge management technologies.

2. Establishing and applying screening criteria to all available sewage sludge management technologies to produce a short list for detailed evaluation.

3. Establishing and applying detailed evaluation criteria to screened/short listed sewage sludge management technologies to determine the preferred technology.


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4. Reviewing preferred sewage sludge management technologies in the northern context.

5. Recommending the “most appropriate” sewage sludge management technologies.

6. Developing means of implementing recommended (or most appropriate) sewage sludge management technologies.

Additional research of the published literature on “air drying” in cold climates suggested that a “freeze thaw” process may provide an optimization consistent with the cold climate of Iqaluit. The particular climate “attributes” of Iqaluit are:

1. Extreme winter cold, with a record low of -46°C in February 1967.

2. Moderate summer warm, with a record high of +26°C in July 2001.

3. Limited moisture, with an average rainfall of 200 mm per year. Freezing and thawing, as an efficient method of sewage sludge conditioning, has been used for many years in cold climates. An important aspect of this process is that the separation of sludge particles and water is generally irreversible. The final separation is achieved when the “released” water drains away from the solids after thawing, leaving a porous sludge with solids content of 20 to 30%. Following this dewatering and drying process, composting may provide stabilization and destruction of pathogens. The composting process will require the addition of bulking materials such as wood chips and cardboard pieces.

Composting of Sewage Biosolids The City of Iqaluit landfill facility has been able to divert sewage biosolids from the first phase of the WWTP. The process plan for the biosolids is to dry the solids throughout the long winter making use of Iqaluit’s cold dry weather, and compost the dried solids during the short warm summers to produce a cover material for the landfill. This process is attractive because the finished material will be non-hazardous and will reduce the use of precious granular material at the landfill - granular material may cost close to $40 per cubic metre in Iqaluit. The timeline for freeze-thaw-composting will be a two-year cycle: freezing will occur from September to May; thawing from May to June; and composting from June to September. The compost would then “mature” from September to May, with the total process taking 20 months from start to finish. This innovation follows in the steps of groundbreaking work by the Bill MacKenzie Humanitarian Society, which proved that composting is feasible in Iqaluit. The innovation captured the attention of the Federation of Canadian Municipalities, which approved a grant application from the City for equipment and testing.


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Figure 12: Composting of Household Organics Material in Iqaluit

Figure 13: Sludge Freeze-Thaw-Composting Area of Landfill Expansion

Compatibility of Sludge Management with Improvements to Landfill In 2006 a major expansion of the City landfill was completed. Sludge management was a significant part of the expansion with a dedicated area developed for sludge freeze-thaw-composting. Overall improvements included on-site and off-site drainage management, and fencing to essentially double the operating footprint of the landfill, providing sufficient capacity through the year 2011.

Although the landfill site has a finite capacity, the integrated waste management approach by the City of Iqaluit has provided the means to divert the biosolids waste stream from the landfill and create a product useful to the ultimate decommissioning of the landfill site. Managing sewage sludge through freeze-thaw-composting is not without its challenges, but the City of Iqaluit, through its progressive management of its utilities, is succeeding. Where other municipalities take for granted the technologies available to them, the arctic must re-engineer the process to suit the environment.

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Livingstone Trail Environmental Control Facility (LTECF), Whitehorse, Yukon By Ken Johnson, MCIP, P.Eng., Senior Engineer, Earth Tech Canada

Glenn Prosko, P.Eng., Project Manager, Earth Tech Canada Published in the Journal of the Northern Territories Water and Waste Association. September, 2005. DEL Communications Inc. Ken Johnson – Editor. Lagoons are the most common type of sewage treatment in Canada, and are often the treatment process of choice for small and medium sized communities because of their very low operating costs, and proven capability to achieve high quality effluent. This is particularly true for high latitudes where for the costs, and operation challenges of mechanical systems are magnified several times. The City of Whitehorse used a four cell primary sewage lagoon system for may years, which provided appropriate technology for this community located at 60°34' N 135°4' W in the Yukon Territory. In the late 1980’s regulatory demands for a higher quality effluent prompted the City to investigate options for achieving a secondary quality or better effluent. A number of studies were completed in the late 80’s and early 90’s considering mechanical and lagoon systems. In the end, the terrain of an area to the north of the City, near what is called the Livingstone Trail, was able to accommodate a large lagoon system. In 1994, work began on the Livingstone Trail Environmental Control Facility (LTECF) to serve the 18,000 people living in the City of Whitehorse. The LTECF includes the following major detention and retention components (See Figure 1).

Figure 1. Livingstone Trail Environmental Control Facility (LTECF)

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• Two 115,000 cubic metre primary lagoons with a combined retention time of 20 days

• Four 293,000 cubic metre secondary lagoons with a combined retention time of 100 days

• One 5.813 million cubic metre Long-Term Storage (LTS) pond with a one-year retention time.

The primary cells can fill to a depth of 6.2 metres and the secondary cells to a depth of 2.3 metres. The long-term storage area, a wetland three kilometres long and two kilometres wide, can fill to a depth of six metres. The flow between the lagoons is controlled by a variety of flow control structures (See Figure 2).

Figure 2. Flow control structure for LTECF.

The facilities were constructed over a period of 2 years, and the work also included clearing and extension of the Marwell forcemain from the old Whitehorse primary lagoons to the LTECF, and upgrading of the other facilities associated with the collection system (See Figure 3). The completion of the work in September 1996, allowed the City of Whitehorse to end the direct discharge of primary treated sewage effluent into the Yukon River. The total capital cost of the LTECF was approximately $20 million ($1996), which was a cost of about $1,100 per resident. The initial design of the facility included a discharge structure from the LTS for a seasonal discharge into the Yukon River. However with such a high quality effluent anticipated from the LTS, the City started considering an opportunity that would accommodate no direct discharge to the Yukon River. Adjacent to the LTS is a glacial pothole lake formation, which lies 16 metres below the level of the surrounding lakes, and lies less than a decimetre above the level of the Yukon River itself. The materials in between the pothole lake and the river are sands and gravels.

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Figure 3. Facilities associated with LTECF.

The City applied to the Yukon Territory Water Board to obtain an additional Class A water licence for a trial discharge of up to two million cubic metres of fully treated effluent into the pothole lake. The discharge would gradually seep into the groundwater, along with other water from the lake, and very slowly make its way to the river. The trial discharge into Pothole Lake (PHL) was a success, and every fall since 1998 treated effluent has been discharged from the LTS pond into the lake (See Figure 4).

Time, wind and sunlight do most of the work at Whitehorse's new sewage lagoon. In a typical July, this City receives approximately 256 hours of bright sunshine and has an average daily temperature of 14°C; the average annual precipitation is 269 mm. The LTECF is designed to hold the sewage for at least 360 days at optimum capacity. During that time, the wind stirs the holding cells and puts oxygen into the system, helping microbes and natural

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Figure 4. Pothole Lake discharge for LTECF. chemical processes to break down the sewage contaminants. The only addition to the system is biological enzyme which enhances biodegradation. By mid May of each year the secondary lagoons are generally "ice-free" and algal blooms quickly develop, significantly increasing the pH levels (maximum 11.3) and dissolved oxygen concentrations (maximum >20 mg/l). The elevated pH levels promote the volatilization of ammonia, reducing levels to below detection (0.005 mg/l) within 5 weeks of becoming ice-free.

The City is generally pleased with the operation of the facility. The water licence states fecal coliform levels in effluent from the system may not exceed 2000 counts per 100 millilitres. Tests of the new system have found fecal coliform counts ranging from less than 3 per 100 millilitres to a high of 240 per 100 millitres. The old system would discharge over 100,000 counts per 100 millilitres.

In 2003 approximately 3,770,000 cubic metres of sewage were received at the LTECF. In 2003 discharge of treated effluent from the LTS into PHL commenced on August 1, 2003 and ended on October 31, 2003, a total of 92 discharge days and a total of 3,374,660 million cubic meters of treated effluent was discharged into the Pot Hole Lake (See Table 1).

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Table 1. Discharge Effluent Quality Water License 2003 Tests

Constituent Max. limit for discharge of treated effluent

Effluent Quality data from LTS

BOD 45 mg/L <4 Suspended Solids 60 mg/L <1 Oils and Grease ** 5 mg/L <1 PH 6-9 7.8 Ammonia N/A <0.05

Faecal Coliforms 2000 MPN/100mL

E.Coli 2000 MPN/100mL <1

Giardia N/A 0 Total Phosphorus N/A 3.32 Dissolved Oxygen N/A 2.1 96-hour static LC50 100% 100 (< symbol) less than detection limit

The Livingstone Trail Environmental Control Facility is a showcase project demonstrating the opportunity for a sewage lagoon system to produce a very high quality sewage effluent at high latitudes in Canada, and essentially have a zero impact on the receiving environment. Certainly it must be recognized that the surrounding natural features have a significant role to play in the treatment processes, and that the end product comes with a significant price tag in capital costs.

PERFORMANCE AND POTENTIAL IMPROVEMENTS TO ANAEROBIC SEWAGE LAGOON IN FORT MCPHERSON, NT Ken Johnson, Earth Tech Canada, Edmonton email: [email protected] Bulmer, Department of Public Works and Services, Government of the Northwest

Territories, Inuvik email: [email protected] Rusnell, Department of Municipal and Community Affairs, Government of the

Northwest Territories, Inuvik email: [email protected] Lanteigne, Earth Tech Canada, Yellowknife

email: [email protected]

ABSTRACT The Hamlet of Fort McPherson is a Gwich’in community located at 67o 27’ N and 134o 53’ W in the Northwest Territories. The main residential sanitary sewage system of the community consists of a trucked pickup, and a lagoon treatment system. Effluent from the lagoon is discharged once or twice a year, and enters a wetland, and stream system that ultimately discharges into the Peel River. The area of the lagoon is approximately 1.81 hectares, and the estimated volume is 100,000 cubic metres. The performance of the sewage lagoon displays the characteristics of an anaerobic lagoon. The effluent suspended solids are in the range of 51 to 150 mg/L, and the effluent BOD5 is in the range of 17 to 70 mg/L. The effluent ammonia concentration is in the range of 11 to 34 mg/L. The sewage lagoon has sufficient hydraulic capacity for the next 20 years, and the effluent quality is well below the existing water licence criteria. However, concerns have been raised by regulatory agencies with the toxicity of the ammonia concentrations in the effluent. The “anaerobic” nature of the lagoon may not easily facilitate nitrification without some mechanical process addition. An overview of the downstream wetland areas, and the quality of the discharge into the Peel River suggests that the wetland areas may have capacity for treating the ammonia in the seasonal lagoon discharge. With the support of additional biophysical studies, the sewage treatment “system” for the lagoon discharge could be expanded in the future to include the downstream wetland areas. KEY WORDS: sewage treatment, cold regions, anaerobic lagoon, wetland discharge





INTRODUCTION Background The Hamlet of Fort McPherson is a Gwich’in community located at 67o 27’ N and 134o 53’ W in the Inuvik Region of the Northwest Territories. The community is located on a high point of land on the east bank of the Peel River about 38 kilometres upstream from its confluence with the Mackenzie River. The level hill where the settlement is located is about 1.9 kilometres long by 0.8 kilometres wide, and is 15 to 21 metres above the summer water level of the Peel Channel. The townsite is 1100 air kilometres northwest of Yellowknife, and the Dempster Highway connects Fort McPherson to Inuvik, 220 kilometres to the northeast, and Whitehorse, Yukon 1200 kilometres to the southwest. Fort McPherson experiences an average of 260 days with frost per year. The mean daily temperature in January is –29 °C, and in July, the warmest month, the mean daily temperature is 15 °C. About 115 mm of rain falls each year, and the the mean annual snowfall is 222 cm (Government of the Northwest Territories, 1982). The sanitary sewage treatment and disposal system for the Hamlet of Fort McPherson is comprised of the trucked sewage system (approximately 85 % of effluent) and a piped sewage system (approximately 15 % of effluent). The trucked sewage system consists of a lagoon constructed in an abandoned shale borrow pit approximately 4 kilometres northeast of the community centre (See Figure 1) (Reid Crowther & Partners Ltd., 1997). The piped sewage system consists of a lake discharge (“Sewage Lake”) immediately to the northwest of the developed community boundary. Effluent from both sewage systems enters a stream system that ultimately discharges into the Peel River, which is 2.5 kilometres downstream of the community centre (Earth Tech Canada, 2002). In 2002 the Hamlet used a total of 39,596 m3 of potable water; the estimated water use is 114 L/c/d, based upon an estimated population of 945 people in 2001 (Government of the Northwest Territories, 2003). The monthly and annual quantities of all wastewater discharged is not metered, but is estimated to equal the quantity of potable water. Approximately 33,300 m3 of wastewater (based upon average operating conditions) was trucked to the sewage lagoon, and the remainder of approximately 6,300 m3 flowed into Sewage Lake (Hamlet of Fort McPherson, 2003). Trucked Lagoon Operation The lagoon is discharged in either the early summer or the fall, depending upon the water level in the lagoon. The discharge timing depends upon when the water level rises within about 1 metres of the top of the lagoon. The lagoon has a limited operating capacity because of a fixed culvert discharge, which limits the operating level variation of the lagoon to about 1.5 metres or 25,000 cubic metres of retention volume.

The lagoon is discharged through the culvert, on the south side of the lagoon, into a 2 kilometre lake. The flow is controlled with a valve which is attached to the end of the culvert on the lagoon side of the culvert (See Figure 2) (Earth Tech Canada, 2003). The flow discharges from the lake approximately to 2 kilometres from the lagoon, and flows into a wetland area before entering a stream that flows another 2 kilometres before discharging into the Peel River (See Figure 1). System Characteristics and Performance Characteristics of Trucked Lagoon The impoundment receiving the sewage is an abandoned gravel quarry, which is generally a rectangular shaped impoundment with an overall length of 190 metres and an overall width of 90 metres; one small area at the north end of the impoundment is approximately 130 metres wide (See Figure 2) (Earth Tech Canada, 2003). The depth of lagoon various significantly, with depths ranging from 5 to 7 metres below the discharge culvert invert elevation. The area of the lagoon is approximately 1.81 hectares, and the estimated volume of the lagoon is 100,000 m3 (Earth Tech Canada, 2003). The sewage treatment and disposal systems operate under the following water licence parameters:

• Effluent Faecal Coliforms 106 CFU/100mL • Effluent BOD5 of seasonal discharge 120 mg/L • Effluent Suspended Solids of seasonal discharge 180 mg/L • Effluent pH of seasonal discharge 6 to 9 • Freeboard minimum in lagoon 1.0 metres

Anearobic Performance of Trucked Lagoon The effluent measurements over the past 7 years (See Figures 3 and 4) (Earth Tech Canada, 2003) demonstrate that the trucked sewage lagoon is well within the water licence parameters (Earth Tech Canada, 2003). The trucked sewage lagoon is a relatively deep (5 to 7 m) manmade impoundment, which operates as an anaerobic lagoon based upon its physical characteristics. The threshold depth for an aerobic pond is less than 1.5 metres, and the threshold depth for an anaerobic pond is greater than 2.5 metres (Metcalf and Eddy Inc., 1979). Very little performance data exists for lagoon systems in the far north. The best comprehensive compilation of performance data has been compiled for lagoons in northern Alberta. The performance characteristics of the Fort McPherson lagoon fall outside the performance characteristics for facultative lagoons in northern Alberta lagoons (less than 2.5 metres deep) (Smith, 1996). The measured range of effluent values for BOD5 (17 to 70 mg/L – 7 year range) in Fort McPherson is above the compiled information for 12 month storage lagoons in northern Alberta (12 to 25 mg/L). The

measured range of effluent values for suspended solids in Fort McPherson (51 to 177 mg/L – 7 year range) is above the compiled information for 12 month storage lagoons in northern Alberta (45 to 80 mg/L). The effluent ammonia concentration in the trucked sewage lagoon remains high, averaging 23 mg/L over 7 years, with a range of 11 to 34 mg/L. These high values suggest that the influent undergoes little or no nitrification. Seasonal Performance of Trucked Lagoon The trucked sewage lagoon is discharged in the early summer and late fall, depending upon the water level in the lagoon. If the lagoon water level rises above the 1 metre freeboard elevation during the winter storage operation, the lagoon is discharged in the spring. Figures 4 and 5 suggest that different effluent characteristics may be expected for spring (before June 30), and fall (after June 30) discharges. A fall discharge may produce higher suspended solids ( 4 year average of 109 mg/L, and a range 46 to 138 mg/l) than a spring discharge (4 year average of 71 mg/L, and a range 42 to 138 mg/L). A fall discharge may produce lower BOD5 (4 year average of 36 mg/L, and a range 22 to 40 mg/L) than spring (4 year average of 51 mg/L, and a range 29 to 88 mg/L). The higher seasonal values for suspended solids in the fall may be attributed to the more quiescent settling conditions in the winter and spring, and the algae growth in the summer months. The lower seasonal BOD5 in the fall may be attributed to the increased biological activity during the summer months. The performance difference for spring and fall discharge has also been documented for the Yellowknife sewage lagoon system. Significant improvements were noted in BOD5 (greater than 85 % removal) and fecal coliforms (less than 1000 CFU/100 mL) in the period following the middle of June where the ambient air temperature reached its warmest for the year (Soniassy, R.N. and Lemon, R., 1986). Characteristics of Peel River Discharge The discharge from both the trucked sewage lagoon (seasonal discharge) enters the continuously flowing small stream that discharges into the Peel River (See Figure 6). The stream near the Peel River has a very small summer discharge (September 2003 observation), but occupies a reasonably large channel with significant stream debris (Earth Tech Canada, 2003). The mean flow in the Peel River itself ranges from 750 to 2000 cubic metres per second during the period between May and September (Environment Canada, 1997). Water samples taken from the stream in early September, 2003 produced the following values (Earth Tech Canada, 2003):

• Suspended solids average of less than 5 mg/L; • BOD5 average of less than 4 mg/L;

• Fecal coliforms average of less than 10 CFU/100 mL; • Ammonia average of 0.28 mg/L.

There is little visible evidence that this stream is a receiving a sewage discharge based upon the limited inspection completed in September, 2003. Although the stream receives a periodic discharge from the trucked sewage lagoon, it also receives a continuous discharge from the piped sewage lagoon (See Figure 1). A fish was also observed in the stream at the time of the inspection. Waste Generation and System Capacities The current sewage generation is estimated to be 114 litres per capita per day based upon the most recent water licence reporting (Hamlet of Fort McPherson, 2003). Of this generation, approximately 85 percent (33,000 m3 in 2002) is trucked sewage, and 15 percent (6300 m3 in 2002) is piped sewage. It is anticipated that these proportions may remain reasonably constant because the servicing strategy is expected to maintain the majority of the community on trucked services, and just the community core on piped services. Table 1 presents a preliminary 20 year estimate of sewage generation based upon the GNWT population projections and the 2002 per capita estimate of sewage generation.

Table 1. Future Sewage Generation (Government of the Northwest Territories, 2003)

Year Population Sewage Generation (m3) in Given Year (114 L/c/d or 41.9 m3/c/year) 2004 982 41,150 2009 1,009 42,280 2014 1,030 43,157 2019 1,055 44,204 2024 1076 45,084 2029 1097 45,964 2034 1119 46,886 2039 1141 47,807 2044 1164 48,771

The estimated volume of the lagoon is 100,000 m3, which provides enough capacity for 12 months of retention beyond the year 2044. It is assumed that 41,000 m3 of trucked sewage will be generated in 2044, which is 85 percent of the total 48,771 m3 estimated in Table 1.

System Improvements and Future Expansion The existing sewage trucked sewage lagoon has sufficient hydraulic capacity for the next 20 years, and beyond, and the effluent quality is well below the existing water licence criteria. The effluent quality could be expected to remain below the existing water licence criteria until the sludge accumulation begins to build up, and ultimately reduces the effluent quality. The addition of primary sewage cells, to reduce the sludge volume in the lagoon, is not a necessary design practice for trucked sewage systems in the far north. Northern retention lagoons are commonly designed with a sludge zone to provide a region for sludge accumulation. Concerns have been raised with the effluent toxicity from the ammonia concentrations in the lagoon influent. The general “anaerobic” nature of the lagoon may not easily facilitate nitrification without the additional of some form of mechanical equipment to the lagoon such as aeration, therefore high ammonia concentrations may be anticipated in the future. The addition of mechanical equipment to the lagoon system is not appropriate technology for the Fort McPherson lagoon because of the northern location of the community, and the distance from the community to the lagoon. The only source of electrical power is in the community itself, which is 4 kilometres away from the lagoon. In anticipation of future demands for effluent quality improvements in toxicity and other parameters, the sewage lagoon system could be expanded to incorporate the downstream water bodies, and wetland areas as part of the overall treatment system (See Figure 6) (Earth Tech Canada, 2003). A preliminary review of these areas (shallow lake area and wetland area), and the discharge quality of the stream into the Peel River suggest that these downstream areas are already providing some degree of treatment to the lagoon discharge. Seasonal wetlands in cold regions have very significant wastewater treatment capabilities. A wetland system in Repulse Bay reduced ammonia concentrations of 50 to 95 mg/L to less that 0.10 mg/L (Johnson, 1994). It would be reasonable to expect that the lake and wetland downstream of the Fort McPherson lagoon could achieve a significant reduction in ammonia concentration; a complete biophysical characterization of the lake and wetland system would be required to estimate the potential reduction. The discharge operation of the trucked sewage lagoon utilizes a culvert with a fixed elevation, which restricts the operating levels in the lagoon to about 1.5 metres (25,000 m3). Future discharge operation of the lagoon should utilize a pumping system in order to draw down the lagoon for a 12 month retention, and a fall discharge (after June 30th).

Conclusions and Recommendations The sewage treatment and disposal facilities for the Hamlet of Fort McPherson have sufficient hydraulic capacity for the next 20 years. In the operation of the lagoon, a fall discharge (after June 30th) may provide an overall higher quality effluent because of the additional retention (12 months in total) over the summer months. To achieve a 12 month retention period, the discharge control culvert may have to be abandoned in favour of a pumping system over the lagoon berm, which would accommodate a greater drawdown in the lagoon water level. The downstream lake and wetland to the lagoon may provide additional treatment of the lagoon effluent with regard to nitrification of the wastewater. Therefore, in responding to existing environmental concerns, and in anticipation of future environmental concerns, and more stringent regulatory guidelines, a biophysical study of the downstream lake and wetland should be undertaken in provide a basis to incorporate the downstream water bodies, and wetland areas as part of the overall treatment system. References: Earth Tech Canada, Fort McPherson Waste Study - Draft Report. October, 2003. Prepared for the Department of Public Works and Services, Government of the Northwest Territories. October. Environment Canada. 1997. Canadian Hydrological Data, Station: 10MC002 PEEL RIVER ABOVE FORT MCPHERSON. Government of the Northwest Territories, Bureau of Statistics. 2003. Government of the Northwest Territories, Bureau of Statistics. December, 1982. Community Water & Sanitation Services. Inuvik Region, Northwest Territories. . Hamlet of Fort McPherson. April, 2003. 2002 Fort McPherson Annual Water Licence Report. Johnson, Kenneth, R. June, 1994. Preliminary Engineering of Sewage Disposal System in the Community of Repulse Bay. Proceedings of the Annual Conference of the Canadian Society for Civil Engineering. Metcalf and Eddy Inc. Wastewater Engineering. 1979. Reid Crowther & Partners Ltd. September, 1997. Operation and Maintenance Manual, Trucked Sewage and Solid Waste Disposal Facilities for Fort McPherson, NWT. Smith, D.W., Technical Editor. 1996. Cold Regions Utilities Monograph, Third Edition, American Society of Civil Engineers.

Soniassy, R.N. and Lemon, R. 1986. Lagoon Treatment of Municipal Sewage Effluent in a Subarctic Region of Canada (Yellowknife, NWT). Water Science Technology, Volume 18, PP 129-139.

Fort McPherson, NWT

Sewage Treatment and Disposal Systems

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LAND USE PLANNING AND WASTE MANAGEMENT IN IQALUIT, NUNAVUT

Ken JohnsonEngineer, Planner, and Surveyor

UMA Engineering [email protected]

The City of Iqaluit, Nunavut, Canada’s newest CapitalCity, is unique in its location, its culture, and itsinfrastructure. Its place in Canada is even moreinteresting given the population of Iqaluit is less than6,000 people. Its infrastructure not only includesspecialized systems for water and sewer delivery andcollection, but also special considerations for wastemanagement. The waste management in Iqaluit includesboth sanitary sewage treatment and disposal, and solidwaste disposal. Both of these waste streams have hadsignificant influence on the development of Iqaluit in thepast, and will continue to have significant influence on thedevelopment into the future.

History of Waste Management

The City of Iqaluit has had a continuing problem withsolid waste management and sewage treatment anddisposal within the community. The history of wastemanagement in Iqaluit has evolved no differently thanmost remote communities, with convenience and low costbeing the original criteria for waste management systems. For solid waste management, this problem began with theuse of multiple solid waste disposal sites by variousmilitary organizations in the 1950s and 1960s; theproblem continued after the military left Iqaluit. The useof the military dump sites, and additional unorganizedsites by the community continued. The end result hasbeen a total of six known community solid waste disposalsites, none of which have incorporated proper wastemanagement techniques, or proper site reclamation.

The sewage treatment and disposal systems for the Cityhave also been problematic, however, prior to 1978, rawsewage was discharged from a number of pipes along theshore. The primary sewage lagoon system whichpresently serves the City of Iqaluit was a majorimprovement to sewage treatment in 1978.

The location of the sewage lagoon has been a concernof the community for many years because of its proximityto the community core and the airport. This proximity hasraised concerns from the perspective of aesthetics, publichealth, and public safety.

The lagoon operation has operated to the generalsatisfaction of the regulatory authorities, however, it hassuffered from a number of catastrophic failures of portionsof the dike structure. These failures have been attributedto both tidal action at the toe of the dikes, and surfacerunoff intrusion and overflows to the top of the dikes.

These failures have been documented in the years 1981,1984 and 1991.

The City of Iqaluit retained consulting expertise in theearly 1990s to provide preliminary engineering forimprovements for solid waste management and sewagetreatment and disposal. The engineering work has alsoincluded work for the cleanup of the existing solid wastedisposal sites within the community.

The consultant’s work on solid waste managementproduced a new landfill site that was placed in operationin 1995. This site represented a significant step forwardin waste management because the site was planned andengineered to include landfill design parameters such ason-site and off-site drainage control, access control andengineered roads, appropriate consideration of setbacks,and operation and maintenance planning. The engineeringof the new landfill also received the appropriate regulatoryscrutiny and approvals in advance of its operation.

The preliminary engineering on sewage treatment anddisposal produced several recommendations for systemimprovements in consideration of the current effluentquality standards, and improved effluent quality standards. In implementing improvements to sewage treatment anddisposal, the City chose to pursue a design build approachto a sewage treatment facility.

The spatial relationships for waste management anddevelopment are now reasonably well defined by theregulatory framework currently in place, withconsiderations of setbacks for residential and commercialdevelopment, natural habitat, and transportation.

However, the waste management practices of the pastcontinue to influence development in Iqaluit becausemany of these setbacks were not been applied or enforced. The waste management activities in and around the Cityinclude five abandoned solid waste sites and a primarysewage lagoon.

Landfill Practices and Spatial Framework inCold Regions

Landfills in cold region communities are evolvingfrom waste management of convenience to engineeredlandfill sites. The evolution of waste management sitesfrom the so-called “dump” to the engineered landfill siteshas occurred over many years, and is far from finished.

Many landfills remain very unsatisfactory toregulatory officials from public health and environmentalimpact perspectives. The reasons behind the remaining


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poor waste management practices are many, and includeinsufficient resources for waste management to anincomplete understanding of what appropriate wastemanagement should include.

The landfills utilized in the cold regions may begenerally categorized into four different types of“depression” types, “embankment” types, “mound” typesand “excavation” types. The depression and embankmenttypes represent landfills developed from conveniencerather than design. The mound and excavation typesrepresent engineered landfills that cold regioncommunities now strive to construct and maintain. Manylocal factors ultimately determine the ultimateconfiguration and location of the landfill in a community. The lining of community landfills in cold regions with anengineered material has never been undertaken and isunlikely to be undertaken in the foreseeable future giventhe added cost and the limited community capital budgets.

The spatial framework for landfills is governed byseveral pieces of legislation, the most significant of whichis the Public Health Act, and the associated Public HealthRegulation. The General Sanitation Regulations to thePublic Health Acts in Nunavut are intended to address thepublic health and safety aspects.

The Regulations state that no building used for humanhabitation shall be:• nearer than 450 m to a waste disposal ground; or• on any site, the soil of which has been made up of any

refuse, unless the refuse has been removed from the siteor has been consolidated or the site has been disinfectedin every case and the site has been approved by a HealthOfficer.

Although the regulation conveys some discretionaryauthority by the Health Officer, in practice, the regulatorshave not exercised any discretion with regard to setbacks.

As well, the Regulations also state that every wastedisposal ground shall be:• located at least 90 m from any public road allowance,

railway, right-of-way, cemetery, highway orthoroughfare; and

• situated at such a distance from any source of water orice for human consumption or ablution that no pollutionshall take place.

Other agencies that are part of the spatial andregulatory framework include: the Nunavut Water Board;the Territorial Department of Renewable Resources; theTerritorial Department of Community Government andTransportation; Transport Canada; Indian and NorthernAffairs Canada; the Department of Fisheries and Oceans;and Environment Canada. Each agency has a regulatoryinfluence in the form of the operations, maintenance,environmental impact or spatial relationship.

Sewage Treatment Practices and SpatialFramework in Cold Regions

A variety of treatment options for wastewatertreatment and disposal are available for cold regioncommunities, however, the ultimate choice for acommunity depends upon technology which is appropriateto the location. The treatment technologies available maybe categorized into the two general areas of mechanicaland non-mechanical treatment, which describes themechanism by which the sewage treatment is completed.

Mechanical treatment may be characterized by theneed for a power supply, construction to accommodatedevices imported to the community, and a reasonablysophisticated operating system. A common example of amechanical system is a rotating biological contactor(RBC).

Non-mechanical treatment may be best characterizedby using the very common example of a sewage lagoon. This system often does not require a power supply, andmay be constructed using mainly local materials. Sewagelagoon systems may be constructed systems or existingnatural impoundments of a natural depression or lakesystem.

Mechanical treatment systems have not been widelyutilized in NWT or Nunavut communities. The use ofmechanical systems in the NWT has, in a number of cases,been unsuccessful. Lagoon systems for cold regions maybe categorized as continuous discharge (short detentionand long detention), intermittent discharge, and zerodischarge.

The regulatory framework for sewage treatment anddisposal is similar to that for solid waste, with similaragency involvement and similar setback requirements.

Land Use Bylaws and Waste Management

The Town’s General Plan Bylaw was developed withsections to specifically address waste management past,present, and future in the context of land use planning.

The specific wording in the Bylaw includes thefollowing passages devoted specifically to wastemanagement:1. The City will continue to evaluate options for long-termsewage treatment, including the relocation of the lagoon,or tertiary sewage treatment at the present site. Theevaluation will consider cost-effectiveness, the degree ofenvironmental protection and the land use implications.2. The City will reserve a site in West 40 (west limit ofthe community) as shown on the Future Land UseConcept as a potential site for the relocation of the sewagelagoon. If another option for sewage treatment is adopted;then other potential uses for that site will be considered. If the best solution is the relocation of the sewage lagoon,the existing site will be restored and consideration given

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to a second or relocated road link between West 40 andthe rest of Iqaluit.3. The City shall continue to evaluate all possible optionsfor an integrated waste management system, including thesuitability of the new landfill suit for long-term use andalso considering complementary strategies such as sourcereduction, reuse, and recycling of waste materials.4. The City shall continue to encourage the responsiblefederal, territorial and other agencies to assist in the cleanup and restoration of the six landfill sites which are thelegacy of fifty years of indiscriminate waste disposal. TheCity shall seek suitable end uses, such as recreational use,for these restored sites.

Future Waste Management

This national spotlight for the City of Iqaluit has givenrise to an increased awareness in many aspects of thecommunity’s infrastructure, particularly wastemanagement. Although the current practice of landfillingand open burning in an engineered landfill site is the statusquo for most of northern Canada, this is no longer adesirable practice in the City of Iqaluit, particularly at thecurrent landfill site in the West 40 area.

A sitting study was recently completed to position theCity of Iqaluit to proceed with the implementation of anew waste management plan. The siting studyencompassed the entire area within the MunicipalBoundary in order to satisfy any potential criticism in thesiting process. Clearly, distance to a site becomes asignificant factor from the onset given that the capital costof an access road may exceed $250,000 per kilometre, andthat operation and maintenance costs in the winter wouldbe very expensive as well.

Ultimately implementation of a site will be based uponenvironmental and land use criteria, technology, andstakeholder and community consultation to gainacceptance of a site. The criteria for an environmentalassessment of any particular site will also vary dependingupon the site. The City of Iqaluit is suggesting that it willpursue the implementation of a solid waste incinerationsystem to be located in the industrially zoned area. Theimplementation of this technology will ultimately dependupon available capital funding (in excess of $3 million),and sustainable operation and maintenance funding (inexcess of $300,000 per year).

The City Iqaluit is also working toward the start-up ofa new tertiary sewage treatment plant which may providehigh quality treatment to serve the City well into thefuture. This $7 million capital project, with an operationand maintenance demand in excess of $400,000 per year,is awaiting completion of project deficiencies.

An interesting opportunity has emerged for some

residents in the Apex neighbourhood of Iqaluit. Atechnology known as wastewater recycling has receivedfunding for a trial program for an 11 house cluster. Thissystem would take wastewater from each house andcomplete a tertiary treatment process before pumping itback to be used to flush toilets and do laundry. Residentswould still get a fresh supply of water for drinking andbathing. The water system is an innovative environmentalproject the City is banking on to conserve Iqaluit’s watersupply Recycling wastewater is expected to reduce waterconsumption (from 1,825,700 litres a year to 912,850litres a year) and cut down the number of water deliveriesto households (4,000 to 100 per year).

The growth in Iqaluit over the past three years has puta tremendous strain on the City’s waste managementsystems. This, in turn, has placed demands andexpectations on the City’s land use planning efforts relatedto waste management.

These improvements to the current waste managementpractices in the City of Iqaluit will improve thepresentation of the community as a Territorial Capital, andalso improve the development situation with regard toregulatory setback requirements for public safety, publichealth, and environmental protection.

Biography

Ken Johnson is an engineer, planner and surveyorfrom St. Albert, Alberta. Ken’s formal training includesa Bachelor’s Degree in Civil Engineering, a Master’sDegree in Civil Engineering, and Certificates in SitePlanning and Survey Technology. Ken is a registeredProfessional Engineer in the Yukon, NorthwestTerritories, and Nunavut, and the Province of Alberta. Ken is also an Associate Member of the Alberta LandSurveyors Association, a Provisional Member of theAlberta Association of the Canadian Institute of Planners,and past Chair of the Cold Region Engineering Divisionof the Canadian Society for Civil Engineering.Ken’s professional experience in the Canadian northspans a period of 14 years; during 5 of these years hespent some time as a resident of each of the 3 TerritorialCapitals. He has worked as far north as Canadian ForcesStation Alert, and to the eastern and western limits of theCanadian north. Ken has provided consulting expertise inthe areas of cold region municipal engineering, coldregion environmental engineering, and land use planningin remote communities. His current areas of interest andstudy are land use planning and climate change in coldregions, on-site wastewater recycling in cold regions, andland use planning and waste management in cold regions.

Figure 1IQALUIT SEWAGE LAGOON Site Plan

Average Influent Concentration


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wastewater treatment and management in northern canada - 2011 edition

Documents

waste association

northern territories

years of northern water

water management system

water management plan

integrated waste management

northern communities

sewage treatment system