table of contents - waste management€¦ · figure 6-32 stage 2 archaeological...

Draft Environmental Assessment West Carleton Environmental Centre

chapter 6. detailed impact assessment of the undertaking

T a b l e o f C o n t e n t s Page

6. Detailed Impact Assessment of the Undertaking ......................................... 6-1

6.1 Preferred Alternative Landfill Footprint Option ...................................................6-2 6.2 Facility Characteristics Report...........................................................................6-5

6.2.1 Waste Quantities and Characteristics ....................................................6-5 6.2.2 Site Entrance .........................................................................................6-5 6.2.3 Stormwater Management ......................................................................6-6 6.2.4 Leachate Management and Treatment ..................................................6-6 6.2.5 Leachate Treatment ..............................................................................6-8 6.2.6 Landfill Gas Management ......................................................................6-9 6.2.7 Landfill Development .............................................................................6-9 6.2.8 Site Materials Balance ...........................................................................6-9 6.2.9 Landfill Operations ................................................................................6-9 6.2.10 Landfill Traffic ...................................................................................... 6-10 6.2.11 Site Closure and End Use ................................................................... 6-10

6.3 Study Area ...................................................................................................... 6-11 6.4 Environmental Components ............................................................................ 6-11 6.5 Methodology ................................................................................................... 6-13 6.6 Key Issues and Design Optimization ............................................................... 6-13 6.7 Net Effects on the Environment ....................................................................... 6-15

6.7.1 Atmospheric Environment ................................................................... 6-15 6.7.1.1 Particulate Matter (Dust) ........................................................ 6-15 6.7.1.2 Combustion Emissions .......................................................... 6-22 6.7.1.3 Odour .................................................................................... 6-26 6.7.1.4 Landfill Gas ........................................................................... 6-36 6.7.1.5 Noise ..................................................................................... 6-41

6.7.2 Geology and Hydrogeology ................................................................. 6-49 6.7.2.1 Geology and Hydrogeology Methodology/Additional

Investigations ........................................................................ 6-49 6.7.2.2 Detailed Description of the Geology and Hydrogeology

Environment Potentially Affected ........................................... 6-51 6.7.2.3 Future Baseline Geology and Hydrogeology Conditions ........ 6-56 6.7.2.4 Potential Geology and Hydrogeology Effects ......................... 6-60 6.7.2.5 Geology and Hydrogeology Mitigation and/or

Compensation Measures ....................................................... 6-65 6.7.2.6 Geology and Hydrogeology Net Effects ................................. 6-68

6.7.3 Surface Water ..................................................................................... 6-68 6.7.3.1 Detailed Description of the Surface Water Environment

Potentially Affected ................................................................ 6-70 6.7.3.2 Potential Effects on Surface Water ........................................ 6-70 6.7.3.3 Surface Water Mitigation and/or Compensation Measures .... 6-71



6.7.3.4 Surface Water Net Effects ..................................................... 6-77 6.7.4 Biology – Terrestrial and Aquatic Environment .................................... 6-77

6.7.4.1 Detailed Description of the Biology Environment

Potentially Affected ................................................................ 6-79 6.7.4.2 Potential Effects on Biology ................................................... 6-86 6.7.4.3 Biology Mitigation and/or Compensation Measures ............... 6-89 6.7.4.4 Biology Net Effects ................................................................ 6-96

6.7.5 Archaeology ........................................................................................ 6-99 6.7.5.1 Detailed Description of the Archaeology Environment

Potentially Affected ................................................................ 6-99 6.7.5.2 Net Effects on Archaeology ................................................... 6-99

6.7.6 Cultural Heritage ................................................................................. 6-99 6.7.6.1 Detailed Description of the Cultural Heritage Environment

Potentially Affected .............................................................. 6-102 6.7.6.2 Potential Effects on Cultural Heritage .................................. 6-103 6.7.6.3 Culture Heritage Mitigation and/or Compensation

Measures ............................................................................ 6-103 6.7.6.4 Culture Heritage Net Effects ................................................ 6-105

6.7.7 Transportation ................................................................................... 6-105 6.7.7.1 Transportation (Effects from Truck Traffic)........................... 6-105 6.7.7.2 Transportation (Integrated Gull Management) ..................... 6-111

6.7.8 Land Use ........................................................................................... 6-114 6.7.8.1 Detailed Description of the Land Use Environment

Potentially Affected .............................................................. 6-114 6.7.8.2 Potential Effects on Land Use .............................................. 6-116 6.7.8.3 Mitigation and/or Compensation Measures for Land Use ..... 6-118 6.7.8.4 Land Use Net Effects ........................................................... 6-118

6.7.9 Agriculture ......................................................................................... 6-119 6.7.9.1 Detailed Description of the Agriculture Environment

Potentially Affected .............................................................. 6-119 6.7.9.2 Potential Effects on Agriculture ............................................ 6-119 6.7.9.3 Mitigation and/or Compensation Measures for Agriculture ... 6-122 6.7.9.4 Net Effects on Agriculture .................................................... 6-122

6.7.10 Socio-Economic Environment ............................................................ 6-122 6.7.10.1 Socio-Economic Environment .............................................. 6-122 6.7.10.2 Visual Environment .............................................................. 6-126

6.8 Summary of Net Effects ................................................................................ 6-137 6.9 Cumulative Effects on the Environment ........................................................ 6-142

6.9.1 Cumulative Effects – Approach ......................................................... 6-142 6.9.2 Valued Ecosystem Components (VEC’s) ........................................... 6-144 6.9.3 Results .............................................................................................. 6-147

6.9.3.1 Significance Assessment ..................................................... 6-147



List of Figures

Figure 6-1 Preferred Alternative Landfill Footprint ............................................................6-4

Figure 6-2 Typical Cross-Section of a Generic II – Double Liner System .........................6-7

Figure 6-3 Detailed Impact Assessment Generic Study Areas ....................................... 6-12

Figure 6-4 Particulate Matter Detailed Impact Assessment Sources and Receptor

Locations ...................................................................................................... 6-17

Figure 6-5 Maximum Predicted 24-Hour TSP Contours ................................................. 6-18

Figure 6-6 Maximum Predicted 24-Hour PM10 Contours ............................................... 6-19

Figure 6-7 Maximum Predicted 24-Hour PM2.5 Contours .............................................. 6-20

Figure 6-8 Combustion Emissions Detailed Impact Assessment Sources and

Receptor Locations ....................................................................................... 6-24

Figure 6-9 Odour Detailed Impact Study Area and Receptor Locations ......................... 6-28

Figure 6-10 Intermediate Operation Year – Preferred Leachate Management System

Isopleths of the Maximum Predicted Odour Concentration - 10-Minute

Average Period ............................................................................................. 6-30

Figure 6-11 Intermediate Operation Year – Contingency Leachate Management

System Isopleths of the Maximum Predicted Odour Concentration - 10-

Minute Average Period ................................................................................. 6-31

Figure 6-12 Final Operation Year – Preferred Leachate Management System

Isopleths of the Maximum Predicted Odour Concentration – 10-Minute

Average Period ............................................................................................. 6-32

Figure 6-13 Final Operation Year – Contingency Leachate Management System

Isopleths of the Maximum Predicted Odour Concentration – 10-Minute

Average Period ............................................................................................. 6-33

Figure 6-14 Landfill Gas Detailed Impact Study Area and Receptor Locations ................ 6-38

Figure 6-15 Noise Detailed Impact Study Area and Receptor Locations .......................... 6-42

Figure 6-16 Geology and Hydrogeology Detailed Impact Assessment Study Area .......... 6-50

Figure 6-17 Modelled Groundwater Heads in the Regional Area, Future Baseline

Conditions .................................................................................................... 6-58

Figure 6-18 Modelled Groundwater Head Contours in the Site-Vicinity, Future

Baseline Conditions ...................................................................................... 6-59

Figure 6-19 Predicted Chloride Concentrations under Future Baseline Conditions .......... 6-61

Figure 6-20 Modelled Groundwater Head Contours in the Site-Vicinity, Assuming

Operation of the New Landfill Footprint and Stormwater Management

Ponds ........................................................................................................... 6-62



Figure 6-21 Predicted Chloride Concentrations, Assuming Operation of the New

Landfill Footprint and Stormwater Management Ponds ................................. 6-64

Figure 6-22 Predicted Chloride Concentrations, Assuming Operation of the New

Landfill Footprint and Stormwater Management Ponds, and with

Mitigation Measures In-Place ........................................................................ 6-67

Figure 6-23 Surface Water Detailed Impact Assessment Study Area .............................. 6-69

Figure 6-24 Proposed Stormwater Management Ponds .................................................. 6-75

Figure 6-25 Conceptual Cross-section – Two Stage Stormwater Facility ......................... 6-76

Figure 6-26 Biology Detailed Impact Assessment Study Area ......................................... 6-78

Figure 6-27 Vegetation Communities ............................................................................... 6-80

Figure 6-28 Wildlife Observations .................................................................................... 6-82

Figure 6-29 Fish Habitat Classification ............................................................................ 6-83

Figure 6-30 Biology Net Environmental Effects ................................................................ 6-98

Figure 6-31 Archaeology Study Area ............................................................................. 6-100

Figure 6-32 Stage 2 Archaeological Assessment ........................................................... 6-101

Figure 6-33 Location of Cultural Heritage Components ................................................. 6-104

Figure 6-34 Transportation Effects from Truck Traffic Detailed Impact Assessment

Study Area .................................................................................................. 6-106

Figure 6-35 Land Use Detailed Impact Assessment Study Area .................................... 6-115

Figure 6-36 Agriculture Detailed Impact Assessment Study Area .................................. 6-120

Figure 6-37 Soils and Farm Locations ........................................................................... 6-121

Figure 6-38 Socio-Economic Detailed Impact Assessment Study Area.......................... 6-123

Figure 6-39 Socio-Economic – Visual Detailed Impact Assessment Study Area ............ 6-127

Figure 6-40 Existing Viewpoints of Preferred Alternative Landfill Footprint Site ............. 6-130

Figure 6-41 Viewpoints of Preferred Alternative Landfill Footprint .................................. 6-131

Figure 6-42 Possible Landscape Treatments to Screen from Adjacent Surrounding

Areas – View from northwest along William Mooney Road of Preferred

Landfill Footprint with no screening treatment. ............................................ 6-133


Areas – View from Northwest along William Mooney Road of Preferred

Landfill Footprint with Possible Natural Landscape Screening Treatment ... 6-134


Areas – View from Southeast Along Carp Road of Preferred Landfill

Footprint with No Screening Treatment ...................................................... 6-134


Areas – View from Southeast Along Carp Road of Preferred Landfill

Footprint with Possible Landscape Screening Treatment ........................... 6-135




Areas – View from Northeast Along Richardson Side Road of the

Preferred Landfill Footprint with No Screening Treatment ........................... 6-135


Areas – View from Northeast Along Richardson Side Road of the

Preferred Landfill Footprint with Possible Landscape Screening

Treatment ................................................................................................... 6-136

Figure 6-48 Additional WCEC Facilities ......................................................................... 6-145

List of Tables

Table 6-1 Key Design Issues Identified in the Detailed Impact Assessment ................. 6-13

Table 6-2 Modifications to the FCR .............................................................................. 6-14

Table 6-3 Potential Increase in Sound Levels over Existing Conditions –

Landfill Operations ........................................................................................ 6-47

Table 6-4 Summary of Vegetation Removed ................................................................ 6-96

Table 6-5 Interior Forest Habitat Removed ................................................................... 6-97

Table 6-6 Intersection Analysis Results ...................................................................... 6-108

Table 6-7 Summary of Predicted Net Effects on the Environment .............................. 6-137

Table 6-8 Description of Additional WCEC Facilities and Existing Projects and

Facilities ..................................................................................................... 6-143

Table 6-9 Valued Ecosystem Components ................................................................. 6-146

Table 6-10 Cumulative Effects ...................................................................................... 6-148

Table 6-11 Interaction of Residual Cumulative Effects with Other Projects and

Activities ..................................................................................................... 6-148

Table 6-12 Significance Assessment Framework ......................................................... 6-149

Table 6-13 Significance of Residual Effects .................................................................. 6-151


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6. Detailed Impact Assessment of the Undertaking

Following the confirmation of Option #2 as the Preferred Alternative Landfill Footprint and Off-

site Effluent Discharge to City of Ottawa Sanitary Sewer in combination with On-site Tree

Irrigation as the Preferred Leachate Treatment Alternative, a Detailed Impact Assessment of the

preferred alternative was undertaken. The purpose of the Detailed Impact Assessment is to

identify the potential environmental effects associated with the implementation of the Preferred

Alternative Landfill Footprint and Leachate Treatment Alternative; to develop mitigation or

compensation measures to address potential adverse environmental effects; and to determine

any remaining net effects following the application of mitigation and/or compensation measures.

The intent of the Detailed Impact Assessment is to review the mitigation measures and resultant

net effects from the Alternative Methods stage within the context of the preliminary design

developed for the Preferred Alternative Landfill Footprint. The preliminary design is presented in

the Facility Characteristic Report (FCR) and outlines the design and operations information for the

Preferred Alternative Landfill Footprint (Option #2) and provides information on the following:

site layout design;

surface water management;

leachate management;

gas management; and,

landfill development sequence and daily operations.

The FCR also provides estimates of parameters relevant to the detailed impact assessment

including estimates of leachate generation, contaminant flux through the liner system, landfill

gas generation, and traffic levels associated with waste and construction materials haulage.

With a more detailed description of the preferred landfill footprint, a more detailed understanding

of the environment was developed by each of the Technical disciplines. The previously

identified potential effects and recommended mitigation or compensation measures associated

with the Preferred Alternative Landfill Footprint in the Comparative Evaluation phase were

reviewed to ensure their accuracy in the context of the preliminary design presented in the FCR.

Based on the review, the potential effects, mitigation or compensation measures, and net

effects associated with the Preferred Alternative Landfill Footprint were confirmed and

documented in stand-alone Detailed Impact Assessment Reports (See Supporting Document

#5). In addition to identifying mitigation or compensation measures, potential enhancement

opportunities as well as monitoring requirements associated with the preliminary design for the

Preferred Alternative Landfill Footprint were also be identified, where possible.


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In addition to assessing the impacts from the preferred landfill footprint option, the technical

disciplines also reviewed the potential impacts from the other WCEC facilities, including the

preferred leachate treatment method. As part of the approved Terms of Reference (ToR), WM

committed to undertaking an assessment of the cumulative effects of the landfill and other

WCEC components/facilities and other non-WCEC projects/activities that are existing, planned

and approved or reasonably foreseeable. The assessment of cumulative environmental effects

is not an aspect normally considered in the OEAA, but is part of the federal EA process under

the Canadian Environmental Assessment Act (CEAA). It should be noted that while the

additional assessment of effects of the non-landfill WCEC components is not required under the

OEAA, it was undertaken based on the ToR commitment and in general, good EA practice.

The technical team reviewed potential impacts on the environment from the additional WCEC

components/facilities, as well as any impacts that may arise from these facilities in tandem/

conjunction with the preferred landfill footprint.

The additional facilities include the following:

A material recycling facility;

A construction and demolition material recycling facility;

An organics processing facility;

Residential diversion facility;

Community lands for parks and recreation;

A landfill-gas-to-energy facility; and

Greenhouses.

Further, the team reviewed other projects/activities within proximity to the landfill, which may act

in a cumulative fashion.

6.1 Preferred Alternative Landfill Footprint Option

In order to undertake the Detailed Impact Assessment it was necessary to further refine the

design plans for the Preferred Alternative Landfill Footprint from the conceptual design stage, as

described in the Conceptual Design Report (CDR) (Supporting Document #2 – Alternative

Methods Evaluation – Landfill Footprint Alternatives). Refinements were based on

additional, more detailed site specific data influencing the engineered features and design of the

landfill. Stakeholder comments received during the EA process were also considered in making

refinements to the landfill footprint. The purpose of the refinements was to further avoid or

mitigate potential adverse environmental effects, as identified in the net effects analysis during

the Alternative Methods phase of the EA. These refinements are captured in the Facility

Characteristics Report (FCR), described in further detail in Section 6.2.


6-3


The southern half of the Preferred Alternative Landfill Footprint is on WM-owned lands and the

northern half is on lands that WM has options to purchase. A 100 m buffer is maintained

between the north limit of the Preferred Footprint and the private lands to the north (e.g., lands

which front onto Richardson Side Road) in accordance with Ontario Regulation 232/98, and an

approximate 350 m buffer is maintained between the east limit of the footprint and Carp Road. A

light industrial building (e.g., the Laurysen building) is situated in the eastern portion of WM

optioned lands, which WM anticipates using for equipment storage/maintenance or waste

diversion activities in the future. An approximate 45 to 50 m buffer is maintained between the

toe of slope of the existing and new landfills, thus allowing sufficient area for a new waste haul

road to the new footprint, and for maintenance and monitoring access. The location of the west

limit of the Preferred Alternative Landfill Footprint was determined by maintaining the noted

buffers and providing the required 6,500,000 m3 capacity, while maintaining the landfill elevation

below 158 mASL (as reported in the CDR) and maintaining side slopes required by Ontario

Regulation 232/98 (e.g., varying from 4H to 1V to 5%). This results in an approximate 146 m

buffer between the west limit of the Preferred Footprint and William Mooney Road. This buffer

preserves a portion of the existing woodlot within the west part of the WM-owned lands.

The final contours of the landfill are shown in Figure 6-1 and reflect a rectangular landform with

a maximum elevation (top of final cover) of 155.7 mASL. This elevation is approximately 30.7 m

above the surrounding existing grade. By comparison, the maximum elevation of the existing

Ottawa WMF landfill is approximately 172 mASL or approximately 47 m above the surrounding

existing grade. The contours reflect maximum side slopes of 4H to 1V, and a minimum slope of

5%. The total footprint area of the new landfill is 37.8 ha.

The base grades for the landfill have been developed such that the base of the landfill liner

system will be at or above the predicted maximum shallow groundwater level.

Slope stability analyses were performed to assess the potential effect of ground motion due to

seismic activity on the slope stability of the landfill and liner system. Eastern Canada is part of

the stable interior of the North American Plate and the damage potential of an earthquake is

determined by how the ground moves. Expected ground motion can be calculated on the basis

of probability, and the expected ground motions are referred to as ‘seismic hazard’. With the

selection of appropriate liner materials, the seismic slope stability analyses results suggested

that the slope stability of the landfill and liner system can have an adequate factor of safety

under seismic condition with the peak ground acceleration. Detailed assessment of stability of

the landfill and liner system will be carried out using updated input parameters during the

detailed design of the landfill to confirm that appropriate materials are selected and to ensure

that adequate factor of safety is achieved.


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Figure 6-1 Preferred Alternative Landfill Footprint


6-5


6.2 Facility Characteristics Report

A Facility Characteristics Report (FCR) was prepared in order to more accurately define

potential environmental effects and mitigation or compensation measures identified for the

Preferred Alternative Landfill Footprint during the Alternative Methods phase of the EA. The

FCR also describes enhancement opportunities and approval requirements associated with the

implementation of the Preferred Alternative Landfill Footprint. The FCR presents preliminary

design and operations information for the Preferred Alternative Landfill Footprint and provides

information on all main aspects of landfill design and operations.

The FCR also provides estimates of parameters relevant to the Detailed Impact Assessment

including estimates of leachate generation, contaminant flux through the liner system, landfill

gas (LFG) generation, and traffic levels associated with waste and construction materials

haulage. The FCR is included as Supporting Document #4 – Facility Characteristics Report.

Key components of the site design outlined in the FCR are summarised in the subsections

below. A description of the other WCEC facilities has been included in the Cumulative Effects

section of this Chapter.

6.2.1 Waste Quantities and Characteristics

WM anticipates receiving an average of 400,000 tonnes/yr of waste over a 10 year period,

consisting primarily of institutional, commercial, and industrial waste, as well as residential

waste and ‘Special’ waste. ‘Special’ waste consists primarily of impacted soils that may be used

for daily or interim cover. The composition of the waste stream is expected to vary based on

actual waste sources.

6.2.2 Site Entrance

Given the location of the Preferred Footprint relative to the existing Ottawa WMF, a new site

entrance is proposed for the WCEC. The new landfill site entrance will be located off Carp

Road, approximately 640 m south of Richardson Side Road. The entrance roadway leading to

the scale facility is approximately 400 m long and will provide truck queuing to address the

potential for queuing on Carp Road. The entrance to the existing Ottawa WMF was deemed not

ideal due to poor sight lines along Carp Road to the north, and close proximity to entrances of

industrial operations on the east side of Carp Road. The proposed entrance location improves

sight lines to the north, maintains adequate separation from the intersection of Richardson Side

Road and Carp Road, and increases distance from the intersection of Carp Road and

Highway 417.


6-6


6.2.3 Stormwater Management

Stormwater management (SWM) for the expanded site will be achieved through integration of

an existing and proposed system of ditches, culverts, storm sewers and ponds that have been

designed to mitigate the impacts of stormwater runoff on water quantity and water quality before

discharge. The proposed SWM system for the new landfill will be similar to the system for the

existing Ottawa WMF landfill in that surface water runoff will recharge to groundwater and will

not directly discharge off-site.

Three new SWM ponds are proposed for the WCEC:

One near the northeast corner of the new landfill to accommodate flow from

the new landfill (once capped) and the maintenance/service road; and

Two near the southeast corner of the new landfill: one to accommodate flow

from the new waste haul road; and one to replace an existing SWM pond that

will be displaced by the new landfill.

Each pond will consist of two stages with flow control between the two stages:

The first stage will be lined and will function as a sedimentation pond and a

containment pond where runoff can be stored;

The second stage will be unlined to permit recharge to groundwater; and

Each stage will be designed to contain a 1:100 year storm event.

6.2.4 Leachate Management and Treatment

WM intends to design the leachate control system for the site with the Generic II – Double Liner

System as specified in Ontario Regulation 232/98, or MOE-approved equivalent. The Generic II

system consists of following components (from top down):

0.3 m thick granular/perforated pipe primary leachate collection system (lcs);

Minimum 0.75 m thick geomembrane/engineered clay composite primary liner;

0.3 m thick granular/perforated pipe secondary lcs;

0.75 m thick geomembrane/engineered clay composite secondary liner; and

1 m thick natural or constructed soil attenuation layer.

The Generic II design also includes suitable separator layers (geotextile or layer of graded

granular material) between the waste and underlying primary lcs, and between granular layers

and soil or liners. A typical cross-section through the liner system is shown in Figure 6-2.


6-7


Figure 6-2 Typical Cross-Section of a Generic II – Double Liner System


6-8


The landfill base grades will be sloped to the northeast toward a single low point, where a

pumping station will convey leachate to a leachate treatment system, and the final cover system

will meet the requirements of Ontario Regulation 232/98.

6.2.5 Leachate Treatment

Preferred Method

The preferred leachate treatment system for the new landfill consists of disposal of leachate

through discharge to the City of Ottawa sanitary sewer system, in tandem with disposal through

irrigation of trees. For sewer disposal, collected leachate may require pretreatment on-site using

either chemical and/or biological processes in order to meet the City’s sewer use by-law. The

leachate effluent would then be discharged to an existing forcemain at Carp Road and Highway

417. The effluent would be further treated at the City’s Robert O. Pickard Environmental Centre

(ROPEC) facility. Leachate would also be disposed through irrigation of poplar and/or willow

trees on-site. The leachate may require partial or full on-site treatment using chemical and/or

biological processes prior to irrigation. The treated leachate will be discharged to the tree

plantation during days with suitable weather conditions. No liquid effluent would leave the

WCEC site.

Contingency Method

As a contingency in the event discharge to the City’s sanitary sewer is unavailable, evaporator

technology could be utilized to dispose of leachate. Leachate from the landfill would be pumped

to an equalization tank that will provide storage to handle peaks in leachate generation. The

leachate would then be fed to the evaporator for processing. The evaporator system may utilize

landfill gas as the energy source to evaporate the leachate or waste heat from the landfill gas

co-generation facility. Depending upon the strength of the leachate and the resulting air quality

emissions, the leachate may have to be pretreated using a chemical and/or biological process

prior to evaporation.

Emergency Method

In an emergency (e.g., if the preferred method were unavailable for a period of time) leachate

could be trucked to one or more wastewater treatment plants outside Ottawa for disposal. The

collected leachate may require pretreatment using chemical and/or biological processes if

required to meet the quality parameters of the receiving wastewater treatment plant(s). The

potential options for receiving the leachate in the surrounding area are not currently known.


6-9


6.2.6 Landfill Gas Management

The proposed LFG collection system for the new landfill will be designed in accordance with

Ontario Regulation 232/98 and will incorporate an active gas collection approach, including a

series of horizontal and vertical collectors that will convey gas to the existing utilization and

flaring facility. Active gas collection will start within several years of commencement of waste

placement to ensure that landfill odour is controlled. Perforated horizontal collectors will be

installed in the landfill as filling progresses. Vertical wells will be installed once the fill

thickness is sufficient.

6.2.7 Landfill Development

For planning purposes it has been assumed that the landfill liner system would be developed in

approximately eight (8) stages with an area of 47,250 m2 each. The size of liner development

stages may be varied during more detailed design work. The layout of the liner stages is shown

in Figure 6-1. The sequence of the proposed development of the new landfill will be as follows:

The liner system will be built in eight, equally-sized stages.

Liner Stages 1 and 2, the new site entrance and roads, scale facility, and

SWM ponds would be constructed prior to commencement of waste receipt.

Liner Stages 3 through 8 will be constructed as required by waste receipts.

Final cover construction will commence after waste filling has reached final

design contours.

6.2.8 Site Materials Balance

The new landfill construction will utilize both on-site and imported materials. It is estimated that

a net volume of 333,000 m3 of fill will need to be imported.

6.2.9 Landfill Operations

The proposed operation of the new landfill will be as follows:

The size of the working face will minimize the area of exposed waste;

The working face location will be adjusted as required to provide shelter from

prevailing winds;

Berms will be constructed as required to attenuate visual and noise impacts;

Portable litter fences will be used around the working face to capture litter;


6-10


Waste compaction will begin immediately after placement and spreading;

Cover material will be readily available and the working face will be fully

covered at the end of each operating day; and,

A comprehensive monitoring and maintenance program will be implemented

to address all aspects of the landfill operation, including waste inspection and

monitoring of landfill odour.

6.2.10 Landfill Traffic

Truck traffic associated with the landfill construction and operation includes trucks hauling waste

and haulage of construction materials for base grading earthworks, liner, leachate collection

system and final cover construction. The traffic analysis used 2005 operating conditions at the

existing Ottawa WMF, which reflected peak activity at the site (i.e., 50 trips per hour - 25 in, 25

out) and was considered to be conservative relative to the new landfill operation. Traffic will also

be generated by importing construction materials.

The proposed site development sequence results in the following traffic scenarios:

Site Preparation Prior to Landfilling: ............................ up to 45 trips/hour

Routine Phase 1 Operations: ...................................... up to 73 trips/hour

Routine Phase 2 Operations: ...................................... up to 50 trips/hour

Phase 2 Operations Approaching Closure: ................. up to 63 trips/hour

6.2.11 Site Closure and End Use

Site closure will follow the completion of the landfill to the approved final contours. Closure

activities include final cover construction, removal of roads and waste receipt facilities that are

not required in the post closure period, and implementation of a long-term monitoring and

maintenance program. The closure plan will be developed as part of EPA-level work. Site end

use will be determined by WM in consultation with the local community and other stakeholders.

Potential end uses may include public open space (e.g., park) that could accommodate various

passive or active recreational activities, or a restricted access open space. Ongoing landfill

monitoring and maintenance requirements will need to be incorporated into End Use planning.


6-11


6.3 Study Area

The general On-Site, Site-Vicinity, and Regional study areas for the Preferred Alternative

Landfill Footprint at the WCEC are shown in Figure 6-3 and listed below:

On-Site ............. the lands required for the Preferred Alternative Landfill

Footprint;

Site-Vicinity ...... the lands in the vicinity of the Preferred Alternative Landfill

Footprint, extending about 500 m in all directions; and,

Regional ........... the lands within approximately 3 to 5 km of the Site and the

Preferred Alternative Landfill Footprint for those disciplines that

require a larger analysis area (i.e., socio-economic, odour,

etc.).

These generic Study Areas were modified during the Detailed Impact Assessment to suit the

requirements of each individual environmental component and to incorporate the Preferred

Leachate Treatment Alternative.

6.4 Environmental Components

Detailed Impact Assessment Reports were prepared for the following disciplines:

Atmospheric (Air Quality,

Combustion Emissions, Odour,

Landfill Gas and Noise)

Geology and Hydrogeology

Surface Water

Biology

Archaeology

Cultural Heritage

Transportation (Effects from Truck Traffic

and Integrated Gull Management)

Land Use

Agriculture

Socio-Economic (including Visual)

A summary of the findings of the Detailed Impact Assessment in relation to each of the

environmental components listed above is provided in the following subsections. The individual

Detailed Impact Assessment reports can be found in Supporting Document #5 – Detailed

Impact Assessment Reports.


6-12


Figure 6-3 Detailed Impact Assessment Generic Study Areas


6-13


6.5 Methodology

The discipline-specific Detailed Impact Assessments were based, in part, on the findings of the

existing conditions investigations and comparative evaluation exercise completed during the

previous stages of the EA. The net effects associated with the four Alternative Landfill Footprint

Options identified during the Alternative Methods phase of the EA were based on conceptual

designs. These effects were reviewed within the context of the preliminary design plans

developed for the Preferred Alternative Landfill Footprint, as identified in the FCR, to determine

the type and extent of any additional investigations required for each discipline to ensure a

comprehensive assessment of net effects.

The previously identified potential effects and recommended mitigation or compensation

measures associated with the Preferred Alternative Landfill Footprint documented in Chapter 5

– Alternative Methods of Carrying out the Undertaking and further in Supporting

Document #2 – Alternative Methods Evaluation – Landfill Footprint Options were reviewed

to ensure their accuracy in the context of the preliminary design for the Preferred Alternative

Landfill Footprint, or updated based on additional investigations carried out during the Detailed

Impact Assessment phase of the EA.

Following this exercise, the requirements for monitoring in relation to net effects were identified

for each discipline, where appropriate. Finally, any approvals required as part of the

implementation of the Preferred Alternative Landfill Footprint were identified.

6.6 Key Issues and Design Optimization

The preliminary results of the Detailed Impact Assessment revealed some key issues in relation

to the proposed design of the Preferred Alternative Landfill Footprint. These key issues, as well

as the recommended mitigation measures through design optimization, are summarized in

Table 6-1 below.

Table 6-1 Key Design Issues Identified in the Detailed Impact Assessment

No. Issue & Explanation Alternative Solutions Recommended Mitigation/

Design Change

1 Groundwater Contamination

from Existing Landfill Groundwater modelling for

existing landfill footprint shows predicted exceedances of

Reasonable Use Guideline B-7 at the northern property line within

10+ years.

Place purge wells between

existing and new landfill footprints Place purge wells on north side

of new landfill footprint Move location of stormwater

ponds to avoid infiltration to groundwater in eastern portion of

the site

Place purge wells between

existing and new landfill footprint


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Table 6-1 Key Design Issues Identified in the Detailed Impact Assessment

No. Issue & Explanation Alternative Solutions Recommended Mitigation/

Design Change

2 Landfill Liner Base Grades/

Groundwater Levels

Infiltration of stormwater through

ponds to groundwater causes

localized changes in predicted

maximum shallow groundwater

level. Separation of liner base

and groundwater levels required

as per regulation 232/98.

Move location of stormwater

ponds to minimize effects on

groundwater levels in eastern

portion of the site.

Change stormwater management

from groundwater infiltration to

surface discharge off-site.

Raise base of landfill liner to

maintain separation distance

from predicted maximum shallow

groundwater levels.

Raise base of landfill liner to

maintain separation distance

from predicted maximum shallow

groundwater levels.

2 Landfill Operation on Noise

Atmospheric (noise) modelling

shows a predicted exceedance at

northeast corner of proposed new

landfill footprint. Issues caused

by proximity of a sensitive

receptor (residence immediately

to the north on land not owned or

optioned by WM), height of

landfill and dispersion of

operational related noise.

Build temporary earth berm

(approx. 7 m high x 100 m long)

along the landfill working face for

each lift

Build waste berm with interim

cover and use as an attenuation

measure until each lift is

complete and covered with final

cover

Build waste berm with interim

cover and use as an attenuation

measure until each lift is

complete and covered with final

cover (Stage 1 and part of Stage

3 only)

3 Site Entrance Impact on Noise

Atmospheric (noise) modelling

shows a predicted exceedance at

northern boundary of proposed

new entrance and access road

for new landfill footprint. Issues

caused by proximity of a sensitive

receptor (residence immediately

to the north on land not owned or

optioned by WM) and dispersion

of related traffic noise at entrance

and along on-site haul road.

Construct berm along northern

property boundary (9 m high x

345 m long) to mitigate noise

effect

Move site entrance to just north

of Laurysen building and

construct berm next to entrance

road (7 m high x 330 m long) to

mitigate noise effect

Move site entrance to just south

of Laurysen building (no berm

required) to mitigate noise effect

Move site entrance to just south

of Laurysen building to mitigate

noise effect

The incorporation of the recommended mitigation measures through design optimization, as

summarized above, required revisions to the FCR. The key differences between the original

FCR and the amended version are outlined in Table 6-2 below.

Table 6-2 Modifications to the FCR

No. Characteristic Original FCR Revised FCR

1 Site Entrance Location Along northern boundary of site South of Laurysen building

2 Landfill Height (due to further refinements of liner level)

156 mASL 155.7 mASL


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The revisions outlined in Table 6-2 are captured in the FCR included as Supporting

Document #4 – Facility Characteristics Report of the EA Report.

The changes made to the FCR based on the preliminary results of the Detailed Impact

Assessment, in turn, required the revision of some of the discipline-specific Detailed Impact

Assessment Reports. The Detailed Impact Assessment Reports that were affected by the

implementation of mitigation measures through design optimization include the following:

Transportation (redesign of left-hand turn lane based on new site entrance

location, change in traffic levels to the site during construction)

Atmospheric – Noise (remodelling of noise contours based on new site

entrance location and berming at the working face)

Geology and Hydrogeology (remodelling groundwater flow and quantity

based on the addition of purge wells along the northern boundary of the

existing landfill)

Biology (recalculation of amount of vegetation and wildlife habitat lost based

on new site entrance location)

The findings of the Detailed Impact Assessment are summarized in the following sections.

6.7 Net Effects on the Environment

6.7.1 Atmospheric Environment

6.7.1.1 Particulate Matter (Dust)

The Particulate Matter Detailed Impact Assessment included the generic On-Site, Site-Vicinity,

and Regional study areas, as shown in Figure 6-3 and described below:

On-Site ............. the lands required for the Preferred Alternative Landfill Footprint;




Preferred Alternative Landfill Footprint.

The Dust Detailed Impact Assessment included emissions from construction, landfilling activities,

and on-site traffic. Potential dust sources were grouped into five general categories including:

On-site roadway sources;

Idling sources;


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Material handling and processing sources;

Wind erosion sources; and

Stack emission sources.

The evaluation considered the potential impacts from the site sources, including the Preferred

Alternative Landfill Footprint, at 24 discrete receptor locations, representing receptors of interest

in the Site-Vicinity and Regional study areas (refer to Figure 6-4). The discrete receptor

locations considered in the dispersion model include nearby residences, schools, businesses,

and other sensitive receptor locations. For all cases, humans were assumed to be present at

these receptors for 24 hours per day. Further details on particulate matter sources, receptors,

and dispersion modelling are found in the Atmospheric (Particulate Matter) Detailed Impact

Assessment Report in Supporting Document #5 – Detailed Impact Assessment.

Particulate Matter Methodology/Additional Investigations

The worst case future build scenario assessed was the first operating year scenario, as it

includes the highest traffic volumes and the scenario places both the landfill and construction

working faces in the worst case locations, in close proximity to the property boundary as well as

discrete sensitive receptors. The future build scenario was assessed by determining the dust

emissions from the significant emission sources and determining the potential off-site impacts

through dispersion modelling. In addition to the first operating year scenario, two proposed

leachate management methods used to treat the leachate were assessed: the preferred method

(excluding leachate evaporator) and the contingency method (including leachate evaporator);

however, as the results were found to be essentially identical, only the results from the more

conservative contingency method are expressed.

No additional Particulate Matter monitoring programs were undertaken as part of the Detailed

Impact Assessment.

Detailed Description of the Environment Potentially Affected by Particulate Matter

On-Site and Site-Vicinity

The maximum predicted off-site particulate matter concentrations associated with the

construction and operation of the Preferred Alternative Landfill Footprint including the

contingency leachate management system is predicted to occur near the property line, north of

the landfill development Stages 1 and 3. The maximum predicted concentration of TSP is

heavily influenced by the close proximity of the bulldozing operations at the construction working

face (in Stage 3) and the exposed areas subject to wind erosion. Contour plots showing the 24-

hour averaged concentrations for TSP, PM 10 and PM 2.5 for the future build scenario are

presented in Figures 6-5 through 6-7.


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Figure 6-4 Particulate Matter Detailed Impact Assessment Sources and Receptor Locations


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Figure 6-5 Maximum Predicted 24-Hour TSP Contours


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Figure 6-6 Maximum Predicted 24-Hour PM10 Contours


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Figure 6-7 Maximum Predicted 24-Hour PM2.5 Contours


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Discrete Receptors

The results of the dispersion modelling indicate that predicted 24-hour TSP, PM10 and PM2.5

concentrations did not exceed the air quality criteria at any of the receptors. Maximum

concentrations for TSP, PM10 and PM2.5 are predicted to occur at Receptor 1 (northeast

corner of the WCEC facility) in the future build scenario.

Potential Effects from Particulate Matter

Predicted concentrations at the discrete receptors do not exceed the Ambient Air Quality

Criteria (AAQC) or Canada Wide Standards (CWS) Limits with the implementation of the

mitigation measures incorporated into the particulate modelling and described in the following

subsection. Consequently, the impact of the expansion is considered low at all discrete

receptors for all future build scenarios.

There are however, particulate matter exceedances at the WCEC property line. These results

assume that the worst-case operations are occurring in the same locations for a five-year

period. In reality, the landfill operations will move to various Stages in the landfill and the

construction operation will only last 6 to 12 months of the modelled period. The impact from the

bulldozing and wind erosion sources will be lessened as the distance between these sources

and the property line increases.

Mitigation and/or Compensation Measures for Particulate Matter

The following mitigation measures were incorporated into the modelling conducted for the

Particulate Matter Detailed Impact Assessment:

Paving internal main haul routes;

Watering and sweeping on all internal haul routes;

Watering suppressants on ancillary sources (crushing activities); and

Installation of water spray on the impact crusher (for C&D waste processing).

The following are recommended additional mitigation measures that may be undertaken as part

of the Dust Best Management Plan:

Watering suppressants on working faces, unpaved interim cover area roads,

construction surfaces, etc.;

Watering suppressants on ancillary sources (Waste Transfer and Processing

Facility (WTPF) sources and other outdoor sources);

Progressive vegetation seeding on surface areas;

Limiting traffic movement on exposed surface areas; and

Speed control of on-site traffic.


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Net Effects from Particulate Matter

When the preferred leachate management system is used or the additional mitigation measures

(as listed above) for the contingency leachate management system are used the predicted

concentrations at the discrete receptors do not exceed the Point of Impingement (POI) Limit.

Consequently, the impact of the expansion is considered low at all discrete receptors for all

future build scenarios.

6.7.1.2 Combustion Emissions

The Combustion Emissions Detailed Impact Assessment included the generic On-Site, Site-

Vicinity, and Regional study areas, as shown in Figure 6-3 and described below:


Footprint;





The air contaminants assessed in the Combustion Emissions Detailed Impact Assessment

include carbon monoxide (CO) and nitrogen oxide (NOx). In addition, impacts from dioxins and

furans (D&F) were assessed based on emissions from the on-site stationary combustion

sources. Predicted concentrations of CO, NOx and D&F were compared against Ontario

Regulation 337 AAQC or other available standards or criteria.

The sources of CO, NOX and D&F considered in the Combustion Emissions Detailed Impact

Assessment include:

vehicles travelling along the on-site haul routes;

idling vehicles;

the landfill gas-fired engines;

the LFG flares;

the sequencing batch reactor (SBR) emergency diesel-fired generator;

the leachate evaporator;

the impact crusher engine; and

vehicles travelling along the adjacent off-site roadways.


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The evaluation considered the potential impacts from site sources including the Preferred

Alternative Landfill Footprint footprint at 24 discrete receptor locations (refer to Figure 6-8),

representing receptors of interest in the Site-Vicinity and the Regional Study Areas. The discrete

receptor locations considered in the dispersion model include nearby residences, schools,

businesses, and other sensitive receptor locations. For all cases, humans were assumed to be

present at these receptors for 24 hours per day. Further details on sources, receptors, and

dispersion modelling are found in the Atmospheric (Combustion Emissions) Detailed Impact

Assessment Report in Supporting Document #5 – Detailed Impact Assessment.

Combustion Emissions Methodology/Additional Investigations

The worst case future build scenario assessed was the first operating year scenario as it has

the highest traffic volumes and the haul routes to the landfill and construction working faces are

positioned in worst case locations, in close proximity to the property boundary and discrete

sensitive receptors. The future build scenario was assessed by determining the combustion

emissions from the significant on-site emission sources and from the predicted 1st year of

operation off-site traffic volumes and determining the potential off-site impacts through

dispersion modelling. In addition to the first operating year scenario, two proposed leachate

management methods used to treat the leachate were assessed: the preferred method

(excluding leachate evaporator) and the contingency method (including leachate evaporator);

however, as the results were found to be essentially identical, only the results from the more

conservative contingency method are expressed.

Detailed Description of the Environment Potentially Affected by Combustion Emissions


Maximum predicted NOx concentrations exceed the AAQC at certain off-site locations; however,

these exceedances are driven by off-site traffic. Maximum predicted NOx concentrations from

WCEC sources are all well within the AAQC for each compound. The maximum predicted CO

and D&F concentrations are less than the AAQC when the WCEC and off-site traffic are

combined.

Discrete Receptors

CO concentrations were predicted to not exceed the 1-hour AAQC at any of the receptors for

the first year of the operation scenario. The maximum predicted 1-hour average concentration

from WCEC sources is 146 g/m3, occurring at Receptor 2. The maximum predicted 1-hour

average concentration from off-site and WCEC sources combined was 2,869 g/m3, occurring at

Receptor 4.


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Figure 6-8 Combustion Emissions Detailed Impact Assessment Sources and Receptor Locations


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CO concentrations were predicted to not exceed the 8-hour AAQC at any of the receptors for the

first year of operation scenario. The maximum predicted 8-hour average concentration from

WCEC sources is 72 g/m3, occurring at Receptor 2. The maximum predicted 1-hour average

concentration from off-site and WCEC sources combined was 937 g/m3, occurring at Receptor 4.

NOx concentrations were predicted to exceed the 1-hour AAQC at three of the receptors, based

on off-site sources. No exceedances of the 1-hour AAQC for NOx are predicted based on

WCEC sources. The maximum predicted 1-hour average NOx concentration was 577 μg/m3 at

Receptor 4. Concentrations predicted at Receptor 2 and Receptor 12 are also exceeding the 1-

hour AAQC.

It is important to note that the predicted impacts at the receptors where exceedances are

predicted are based mainly on the contribution from the off-site roadways. The WCEC sources

are contributing only a small percentage of the maximum predicted impact at these receptors.

NOX concentrations were predicted to not exceed the 24-hour AAQC at any of the receptors for

the first year of operation scenario. The maximum predicted 24-hour average concentration

from WCEC sources is 12 g/m3, occurring at both Receptor 2 and Receptor 4. The maximum

predicted 24-hour average concentration from off-site and WCEC sources combined was

97 g/m3, occurring at Receptor 4.

D&F concentrations were predicted to not exceed the 24-hour AAQC at any of the receptors.

Potential Effects from Combustion Emission

For CO and D&F the predicted impacts do not exceed the applicable AAQC at any off-site

location. The 1-hour NOX is predicted to exceed the AAQC at off-site locations, including three

of the discrete receptor locations. The 24-hour NOX is predicted to exceed the AAQC at some

off-site locations; however, it is not predicted to exceed the AAQC at any of the discrete

receptor locations.

The predicted NOX exceedances are a product of the high traffic volumes along off-site

roadways, especially Highway 417. Exceedances of the 1-hour NOX AAQC from time-to-time

are not unexpected at locations near a 400-series highway in Ontario. The contribution from

WCEC sources to the predicted NOX exceedances is low. Consequently, the impact of the

expansion is considered low at all discrete receptors for all future build scenarios.


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Mitigation and/or Compensation Measures for Combustion Emissions

The following measures not incorporated into the modelling may be implemented in order to

further mitigate Combustion Emission effects:

Minimizing on-site idling of vehicles;

Routine monitoring for waste vehicles arriving to the site in unfit or un-

maintained conditions; and

Proper staging and planning for internal vehicles arriving at the site and site

sequencing.

The predicted environmental impacts of CO and NOx are largely dominated by the presence of

traffic on off-site roadways; therefore, the additional mitigation measures for WCEC sources are

not expected to have a significant impact on off-site concentrations. The predicted

environmental impacts of D&F are dominated by WCEC sources; however, the maximum

predicted concentrations of D&F represent only a small percentage of the AAQC. The proposed

mitigation measures are not expected to have a significant impact on the D&F emissions from

on-site sources.

Net Effects from Combustion Emissions

The predicted concentrations at the discrete receptors do not exceed the AAQC for CO, D&F, or

24-hour NOX. Although exceedances are predicted for 1-hour NOX at three of the discrete

receptor locations, these exceedances are a result of off-site traffic, with only a minor

contribution from WCEC sources. Consequently, the impact of the expansion is considered low

at all discrete receptors for all future build scenarios.

6.7.1.3 Odour

The Odour Detailed Impact Assessment included the generic On-Site, Site-Vicinity and

Regional study areas, as shown in Figure 6-3 and described below:


Footprint;






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Under normal operating conditions, solid waste landfills have the potential to produce odours

from several areas, including:

LFG and garbage odours from the landfill and waste acceptance activities:

working face, interim cover areas, final cover areas, public waste drop off

areas, installation of LFG wells, trenching activities, and cracks/fissures in the

landfill cover;

Leachate odours from the leachate management system;

Hydrocarbon odours from the use of contaminated soils as cover materials;

and,

Compost odours from the spreading of compost on the landfill mound to

encourage vegetation growth.

The evaluation considered the potential impacts from the WCEC odour sources including the

Preferred Alternative Landfill Footprint at 24 discrete receptor locations (refer to Figure 6-9),

representing receptors of interest in the Site-Vicinity and the Regional Study Areas. The discrete

receptor locations, considered in the dispersion model, include nearby residences, schools,

businesses, and other sensitive receptor locations. For all cases, humans were assumed to be

present at these receptors for 24 hours per day. In addition, the modelling was performed using

a receptor grid covering the Site-Vicinity and Regional Study Areas to produce isopleths of

predicted concentrations. Further details on odour sources, receptors, and dispersion modelling

are found in the Atmospheric (Odour) Detailed Impact Assessment Report in Supporting

Document #5 – Detailed Impact Assessment.

Odour Methodology/Additional Investigations

The potential odour impacts that would result from the construction and operation of the

Preferred Alternative Landfill Footprint were assessed at the worst case future build stages and

phases of development. The future build scenarios were assessed by determining odour

associated with the significant emission sources in each scenario and determining the potential

off-site impacts through dispersion modelling. The scenarios assessed include the intermediate

operation scenario and final operation scenario. In addition to the two operation scenarios, two

proposed leachate management methods used to treat the leachate were assessed: the

preferred method (pre-treatment with discharge to City of Ottawa sanitary sewer) and the

contingency method (pre-treatment with leachate evaporator); however, as the results were

found to be essentially identical, only the results from the more conservative contingency

method are expressed.


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Figure 6-9 Odour Detailed Impact Study Area and Receptor Locations


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The odour impacts from the WCEC operations were determined using a dispersion model and

reasonable worst-case emission rates. Dispersion modelling was performed using the U.S. EPA’s

AERMOD dispersion model (AERMOD) to predict concentrations of odour emitted from the WCEC

Preferred Alternative Landfill Footprint operations at various receptors within the Study Area.

Detailed Description of the Environment Potentially Affected by Odour


The combined odour impact from the site-wide WCEC operations was predicted to exceed the

recommended annoyance guideline of 3 OU/m3. For all scenarios, the exceedances were

predicted to occur near the facility property line. The maximum 10-minute averaged concentration

at any modelled receptor for 2018 conditions was predicted to be 10.0 OU/m³. The maximum 10-

minute averaged concentration at any modelled receptor for 2023 conditions was predicted to be

12.2 OU/m³. Contour plots showing the 10-minute average concentrations for odour for each

scenario are presented in Figure 6-10 through Figure 6-13. The contour plots also illustrate the

off-site area where odour impacts from the WCEC operations may exceed the 1 OU/m³ detection

threshold and the 3 OU/m³ annoyance threshold from time to time.

The maximum predicted odour concentration occurring from the landfill sources are influenced by

the close proximity of these sources to the property line. The working face was generally the most

dominant landfill source in causing off-site impacts. The working face represents the landfill

source with the highest emission flux rate (odour emissions per square metre), due to the deposit

and handling of fresh waste, reduced gas collection efficiency, and a lack of cover material in this

area. The predicted impacts from the existing landfill mound are predicted to decrease in the later

years, relative to the intermediate years, due to the reduction in LFG produced from the existing

landfill in future years. The predicted impacts from the Preferred Alternative Landfill Footprint

increased in the later years, relative to the intermediate years, as a result of increased waste

present in the Preferred Alternative Landfill Footprint in future years, which results in increased

LFG generation, and thus increased odour emissions, from this source.

The maximum predicted odour concentrations for all future build scenarios are influenced by the

SBR system. The SBR system is comprised of several tanks, which have vent exhausts with low

exit velocities and little momentum, resulting in poor dispersion from these sources. The poor

dispersion results in high concentrations at the property line. In comparison, the leachate evaporator

stack exhaust, evaluated as part of the contingency leachate management system, has a tall stack,

high exit velocity, and high momentum, resulting in good dispersion. For these reasons, the leachate

evaporator has little impact on the maximum predicted odour concentration at the property line, as

the maximum predicted concentrations between the Preferred Leachate Management System and

the Contingency Leachate Management System are relatively unchanged.


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Figure 6-10 Intermediate Operation Year – Preferred Leachate Management System Isopleths of the Maximum Predicted Odour Concentration - 10-Minute Average Period


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Figure 6-11 Intermediate Operation Year – Contingency Leachate Management System Isopleths of the Maximum Predicted Odour Concentration - 10-Minute Average Period

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