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HUNTER WATER

Integrated Assessment of Monitoring

Burwood Beach WWTW

301020-03413

December 2013

Infrastructure & Environment 8-14 Telford Street Newcastle East NSW 2300 Australia Tel: +61 2 4907 5300 Fax: +61 2 4907 5333 www.worleyparsons.com WorleyParsons Services Pty Ltd ABN 61 001 279 812

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INTEGRATED ASSESSMENT OF MONITORING

BURWOOD BEACH WWTW

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SYNOPSIS

The aim of the Burwood Beach Marine Environmental Assessment Program (MEAP) was to establish

the impact footprint of the existing outfalls, establish the gradient of impact with distance from the

outfalls and to assess the likely impact of future discharges. Following the concepts and monitoring

framework set out in the ANZECC/ARMCANZ Guidelines (2000), a series of integrated monitoring

tasks have been used to identify potential changes in selected indicators at a range of reporting

scales (temporal and spatial) and habitat types. The MEAP incorporates a mix of complementary

physical, chemical and biological indicators to assess the overall effect of wastewaters, effluent and

biosolids, on the ecological health of the marine ecosystem. This affords a more complete overall

assessment or ‘weight of evidence’ in relation to ecosystem health.

The MEAP began in June 2011, and was completed in September 2013. This integration report

provides an assessment of the environmental impact and the current environmental performance of

the Burwood Beach discharge as it affects the receiving waters and their associated ecosystems.

Flows from Burwood Beach WWTW represent a combination of secondary treated effluent flows,

biosolids flows and by-pass flows. In dry weather, the effluent discharge averages 44 million litres per

day (44 ML/d) and over the course of the study the average discharge of treated effluent (including

wet weather events) was 57 ML/d. During most months of the study, there were bypass flows with a

monthly average of 218 ML.

The type and extent of impact associated with WWTWs varies and depends on the quantity and

composition of sewage effluent, the dilution and the frequency and duration of exposure as well as

environmental factors such as currents. The dilution produced by the effluent and biosolids outfalls

has been modelled to be 1:120 and 1:200 dilution, respectively. The final treated effluent and

biosolids from Burwood Beach WWTW has been monitored by Hunter Water for physicochemical

parameters, microbiological indicators of faecal contaminations and for a suite of metals/metalloids

and organic chemicals. Using the modeled dilution factors, this gives an estimate of the expected

concentrations in the receiving environment.

The Burwood Beach outfalls are located on a section of coastline where there are extensive sandy

beaches with intermittent intertidal rock platform habitats. Water depth is approximately 22 m at the

location of the outfalls’ diffusers. The seabed consists of small areas of patchy rocky reef,

interspersed between large areas of soft sediment (sandy) habitat. The reef is predominantly low

profile, extending approximately 1 m above the sand. Directly inshore of the diffuser is a patch of

higher relief reef with ledges, overhangs and crevices. The reef areas are subject to strong wave

action and periodic sand inundation, particularly on low profile reefs. Suspended sediments

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significantly attenuate light penetration through the water column and limited light availability is likely

to restrict most algal to shallower reefs in the area.

The water quality results indicate a zone of detectable impact extending to about 500 m from the

outfalls. Water quality within 500 m of the Burwood Beach WWTW outfalls does not always meet the

ANZECC/ARMCANZ (2000) guidelines, NSW Marine Water Quality Objectives (NSW EPA 2000) or

NHMRC (2008) guidelines. However the diffusers are almost 2 km offshore and well away from

swimming and surfing areas. Concentrations of most nutrients generally met the guidelines while

concentrations of faecal indicators (faecal coliforms and enterococci) seldom met the guidelines.

Ecotoxicology testing showed toxicity of effluent and biosolids at concentrations ranging from 12.5-

50% dilution in all measured DTA tests and further investigations confirmed that the major cause of

effluent toxicity in two of the three tests was ammonia. The modeled dilution for the current discharge

of effluent and biosolids outfalls should be sufficient to reduce ammonia concentrations to below the

ANZECC (2000) toxicant trigger value for ammonia of 0.91 mg/L, which corresponds to the 95%

species protection level for marine waters.

The sediment quality assessment showed a lack of consistent findings suggesting the effluent and

biosolids are mixed fairly rapidly and do not accumulate in the vicinity of the discharge point for any

extended duration. The total organic carbon is slightly elevated within 20 m of the biosolids diffuser.

Bioaccumulation studies in oysters and fish showed that there was no evidence of bioaccumulation of

the tested metals in organisms from Burwood Beach in comparison to reference locations. The

Oyster Study detected low concentrations of organochlorines in only one sampling event, suggesting

intermittent presence around the outfalls. The Seafood Bioaccumulation Study found sporadic

elevated levels of thermotolerant coliforms and E. coli in samples of yellowtail scad and snapper, fish

that are commonly targeted, in particular by commercial fisherman, around the Burwood Beach

outfalls. On average, E. coli levels in fish from Burwood Beach consistently exceeded the NSW FA

(2001) guideline for ready to eat food, although this would be applicable only where seafood is

consumed raw.

The anticipated response in infaunal communities from organic enrichment of sediments caused by

the discharge of biosolids particulates was inconclusive. An increase in the polychaete ratio was

noted, however the inference was weak as the increase was not consistent across sampling periods

and was also limited spatially to within 20m of the discharge. Other responses noted were the

increase in the numbers of fish around the discharge and the changes in reef species assemblages

around the outfalls.

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Overall, the discharge of effluent and biosolids from the Burwood Beach outfalls is having a localised

effect on ecological conditions in the receiving environment. No large scale or regional effects were

observed during the MEAP as biological effects were subtle and localised to within 50 m of the

discharge. The Burwood Beach outfalls are located in a high energy environment with intermittent

sand movement which is likely to act as a disturbance mechanism and influence the structure of

benthic communities, primarily infauna and low profile reef, masking any potential impact from the

discharge.

In contrast the discharge of effluent and biosolids from the Burwood Beach outfalls has created a

zone of detectable impact on water quality that extends to about 500 m from the outfalls, Water

quality within this zone does not always meet the ANZECC/ARMCANZ (2000), NSW Marine Water

Quality Objectives (NSW EPA 2000) or NHMRC (2008) guidelines. Concentrations of most nutrients

generally met the guidelines while concentrations of faecal indicators (faecal coliforms and

enterococci) seldom met the guidelines.

From a water quality perspective, an increase in volume of discharge without any improvements in

treatment is likely to expand the zone and increase the frequency of non-compliance associated with

ammonia, enterococci and faecal coliforms and most likely also increase the spatial extent of non-

compliance. Similarly if the basis of current non-compliance is around protection of beneficial uses,

then any changes to treatment should focus on removal of pathogens. This will produce an overall

benefit of reducing the overall nutrient load to the receiving environment and further reduce any risk to

human health. Ammonia concentrations within 500 m of the outfalls also exceeded the ANZECC

(2000) trigger level of 0.02 mg/L, which could potentially increase regional phytoplankton growth. No

local stimulation of reef biota or infauna due to nutrient discharges was identified in the MEAP.

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A summary of the current performance of impacts from Burwood Beach WWTW is provided in Table

1.1.

Table 1.1 Summary of Environmental Impact Assessment based on MEAP Results

Impacts Assessed Evidence from MEAP Outcome

Water Quality Effects Extensive sampling showed that concentrations of ammonia, total nitrogen, total phosphorus, enterococci and faecal coliforms are higher at outfall and decreased with distance from outfalls. Effects of outfalls on water quality were detectible to 500 m from outfalls.

High ambient nitrogen at outfalls and at reference sites.

LOCAL IMPACT – can detect local increase in water quality parameters to 500 m from outfalls

Toxicity Effects Extensive testing of toxicity showed that biosolids is somewhat more toxic than effluent. Ammonia is the principal cause of toxicity in two of the three tests but noted that there may be additional factors at times. Initial dilution should be sufficient to have no toxic effect from effluent or biosolids in the receiving waters, as present dilution reduces levels to below the ANZECC (2000) guideline for ammonia for 95% protection of species.

NO IMPACT in receiving waters due to high dilution

Sediment Quality - TOC

Consistent increase in TOC in sediments within 20 m of diffusers, largely attributed to high amount of solids in biosolids.

LOCAL IMPACT – can detect higher TOC in sediments within 20 m of diffusers

Accumulation of Contaminants in sediments

No accumulation of pesticides (OC, PCB and OP) in sediments. Some metals slightly elevated in sediments near outfall (copper, zinc, barium, lead, mercury) although all metal levels less than ANZECC (2000) low impact guidelines.

LOCAL IMPACT –higher metals in sediments within 50 m of diffusers

Infauna Community Large natural variability in infauna populations and thus difficult to detect any consistent change in community structure. Likely that the higher TOC supports higher polychaete population within 20 m of outfalls.

POSSIBLE LOCAL IMPACT – more polychaetes within 20 m of diffusers

Reef Flora and Fauna Reefs at and near outfalls are low profile and subject to sand abrasion in storms and occasional inundation

NO IMPACT detected on reef

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by sand. Small number of pioneer species found, with low abundance, richness and diversity, Natural stresses likely overwhelm any effect caused by discharges.

communities in relation to high natural stresses

Fish Increased abundance of fish at the outfalls, although diversity and richness the same at outfall sites and reference sites. Thus fish attracted to food in discharges and rising plumes are a fish “attractor”.

LOCAL IMPACT – can detect more fish within 25 to 50 m of diffusers

Bioaccumulation in oysters and fish

Oyster biomonitoring study found similar concentrations of metal and organic contaminants at outfall sites, mixing zone sites and reference sites. Thus inputs from the land and ambient background are larger than any effect of the outfalls.

No accumulation of pesticides (OC, PCB and OP) in fish.

NO IMPACT detected

Micro-biological Contamination

About 10 to 20 per cent of Yellowtail caught at outfalls had elevated faecal coliforms and E. coli in edible fillets, which was likely to be in the skin.

LOCAL IMPACT – fish must be cooked

Bathing Water Quality Elevated levels of faecal coliforms and enterococci detected to 500 m from diffusers.

LOCAL IMPACT –to 500 m from outfalls

Plume Visibility Plume generally visible from boat above outfall LOCAL IMPACT

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Disclaimer

This report has been prepared on behalf of and for the exclusive use of Hunter Water, and is subject

to and issued in accordance with the agreement between Hunter Water and WorleyParsons Services

Pty Ltd. WorleyParsons Services Pty Ltd accepts no liability or responsibility whatsoever for it in

respect of any use of or reliance upon this report by any third party.

Copying this report without the permission of Hunter Water and WorleyParsons Services Pty Ltd is

not permitted.

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PROJECT 301020-03413 – BURWOOD BEACH INTEGRATED ASSESSMENT OF MONITORING

REV DESCRIPTION ORIG REVIEW WORLEY- PARSONS APPROVAL

DATE CLIENT APPROVAL

DATE

A Issued for internal review

K Stewart/ H Houridis

Dr M Priestley

12 November 2013

N/A

B Issued for client review Dr M Priestley

HWC/ CEE

C Issued for internal review H Houridis/ Dr M

Priestley

M Priestley

14 December 2013

D Issued for client review Dr M Priestley

HWC/ CEE

14 December 2013

E Final Draft issued to Client Dr M Priestley

HWC 19 December 2013

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301020-03413 Final Draft December 2013

CONTENTS

1. INTRODUCTION .............................................................................................................. 14

1.1 Objectives of Monitoring Program .................................................................................... 14

1.2 Objectives of the Integration Report ................................................................................. 14

1.3 Outline of Report ............................................................................................................... 14

2. BACKGROUND INFORMATION ...................................................................................... 16

2.1 Burwood Beach WWTW ................................................................................................... 16

2.2 Effluent and Biosolids Flows ............................................................................................. 18

2.2.1 Effluent and Biosolids Discharges ....................................................................... 18

2.3 Existing Quality ................................................................................................................. 20

2.3.1 Nutrients ............................................................................................................... 21

2.3.2 Chemicals ............................................................................................................ 21

2.3.3 Other Parameters................................................................................................. 21

2.3.4 Loads of Constituents Discharges ....................................................................... 22

2.4 Arrangements of Outfalls .................................................................................................. 22

2.5 Dilution Modeling / Dispersion Characteristics ................................................................. 25

2.6 Upgrades .......................................................................................................................... 26

2.7 Receiving Environment ..................................................................................................... 27

2.7.1 Metocean Conditions ........................................................................................... 27

2.7.2 Beach Water Quality ............................................................................................ 29

2.7.3 Sediment Quality .................................................................................................. 30

2.7.4 Nearby Potential Pollutant Sources ..................................................................... 31

2.7.5 Surrounding Marine Habitats ............................................................................... 32

3. ENVIRONMENT QUALITY ASSESSMENT ..................................................................... 34

3.1 Water Quality .................................................................................................................... 34

3.2 Sediment Quality............................................................................................................... 34

3.3 Toxicity .............................................................................................................................. 35

3.4 Bioaccumulation ................................................................................................................ 36

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3.5 Human Health ................................................................................................................... 36

3.6 Habitat and Ecosystem ..................................................................................................... 37

4. MONITORING PROGRAM ............................................................................................... 39

4.1 Overview of MEAP ............................................................................................................ 39

4.1.1 Development ........................................................................................................ 39

4.1.2 Consultation ......................................................................................................... 39

4.1.3 Previous studies/limitations .................................................................................. 40

4.1.4 Design .................................................................................................................. 40

4.1.5 Implementation..................................................................................................... 40

4.2 Component Studies and Impacts ...................................................................................... 41

4.2.1 Water Quality ....................................................................................................... 41

4.2.2 Marine Sediment .................................................................................................. 47

4.2.3 Ecotoxicology ....................................................................................................... 51

4.2.4 Oyster Biomonitoring ........................................................................................... 53

4.2.5 Seafood Bioaccumulation .................................................................................... 54

4.2.6 Human Health Risk Assessment ......................................................................... 55

4.2.7 Reef Ecology ........................................................................................................ 57

4.2.8 Fish Distribution Study ......................................................................................... 58

4.2.9 Marine Infauna ..................................................................................................... 58

4.3 Summary ........................................................................................................................... 59

5. INTEGRATED MONITORING ASSESSMENT ................................................................ 62

5.1 Assessment Framework ................................................................................................... 62

5.2 Key Processes and Conceptual Models ........................................................................... 64

5.3 Decision Criteria ................................................................................................................ 68

5.3.1 Environmental Values and Water Quality Objectives .......................................... 68

5.3.2 Trigger Values ...................................................................................................... 70

5.3.3 Statistical Analysis ............................................................................................... 71

6. ECOLOGICAL IMPACT ASSESSMENT .......................................................................... 72

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6.1 Potential Impacts .............................................................................................................. 72

6.2 Toxicity .............................................................................................................................. 74

6.2.1 Implications .......................................................................................................... 76

6.3 Water quality objectives .................................................................................................... 77

6.3.1 Implications .......................................................................................................... 80

6.4 Sediment Quality............................................................................................................... 80

6.4.1 Implications .......................................................................................................... 81

6.5 Marine Infauna .................................................................................................................. 81

6.5.1 Implications .......................................................................................................... 82

6.6 Reef Communities ............................................................................................................ 82

6.6.1 Implications .......................................................................................................... 83

6.7 Fish Assemblages............................................................................................................. 83

6.7.1 Implications .......................................................................................................... 83

6.8 Assessment of Current Performance ................................................................................ 83

6.9 Projections of Future Effects ............................................................................................. 89

6.9.1 Increased Flows and Loads ................................................................................. 89

6.9.2 Reducing Biosolids Discharge ............................................................................. 94

6.9.3 Reducing Nutrient Discharges ............................................................................. 96

7. CONCLUSIONS ................................................................................................................ 99

8. REFERENCES ............................................................................................................... 102

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Tables

Table 1.1 Summary of Environmental Impact Assessment based on MEAP Results ............................ v

Table 2.1 Effluent and biosolids flow data for the study period (July 2011 - May 2013). ..................... 19

Table 2.2 Effluent and Biosolids characteristics and estimated signature after dilution ....................... 21

Table 2.3 Estimated ratio of biosolids to effluent for selected parameters ........................................... 22

Table 2.4 Potential Upgrade Options. (Hunter Water 2013b). .............................................................. 26

Table 2.5. Mean Monthly Surface Seawater Temperature (°C) for Newcastle ..................................... 29

Table 4.1 Analytical parameters showing their respective LOR and guideline values. ........................ 42

Table 4.2 Samples that exceeded the associated water quality guideline values. ............................... 44

Table 4.3 Summary of median and 95th percentile data by zone ........................................................ 47

Table 4.4. Summary of significant observations from the monitoring studies....................................... 60

Table 5.1. Marine Values and Water Quality Indicators for the Hunter catchment area. ..................... 69

Table 6.1 Summary of Impact Assessment associated with Discharge of Effluent and Biosolids,

Burwood Beach ..................................................................................................................................... 73

Table 6.2 Summary of Environmental Impact Assessment based on MEAP Results .......................... 88

Table 6.3 Summary of Environmental Impact Assessment for Scenario – Increase in Discharges by

23 % to year 2031. ................................................................................................................................ 93

Table 6.4 Summary of Environmental Impact Assessment for Scenario– Change from Ocean

Discharge of biosolids to Land Recycling ............................................................................................. 95

Table 6.5 Summary of Environmental Impact Assessment for Scenario– Install Biological Nutrient

Remover (BNR) to Reduce Ammonia and Nitrogen Discharges and Disinfection ............................... 98

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Figures

Figure 2.1. Location of Burwood Beach WWTW. ................................................................................. 17

Figure 2.2 Effluent and biosolids flow data for the study period (July 2011 – May 2013). ................... 20

Figure 2.3. Burwood Beach WWTW and outfalls alignment. ................................................................ 24

Figure 4.1. Boxplots showing standardised metal concentrations for each zone. ................................ 50

Figure 5.1 MEAP Framework of assessment ...................................................................................... 63

Figure 5.2 Concept of Impact Pathways for changes in Nutrients ....................................................... 65

Figure 5.3 Concept of Impact Pathways for changes in Dissolved Oxygen, Pathogens and Toxicants

............................................................................................................................................................... 66

Figure 5.4 Concept of Impact Pathways for changes in Particulate Matter .......................................... 67

Figure 6.1 Percentage NOEC based on sea urchin fertilization test from 1996-2013. Note that

effluent min and max dilutions in 2013 were both 100 % NOEC. ......................................................... 74

Figure 6.2 Percentage NOEC based on sea urchin larval development test, 1996-2013. Note that

effluent min dilution in 2013 was 6.3%. ................................................................................................. 75

Figure 6.3 Percentage NOEC based on microalgal inhibition test, 1996-2013. ................................... 75

Figure 6.4 Ammonia Concentrations, June 2012 ................................................................................. 78

Figure 6.5 Ammonia Concentrations, October 2012 ............................................................................. 78

Figure 6.6 Enterococci Concentrations, June 2012 ............................................................................. 79

Figure 6.7 Enterococci Concentrations, October 2012 ......................................................................... 79

Figure 6.8 Inferred impact zone based on monitoring of ammonia in the Water Quality Study during

June 2012. ............................................................................................................................................. 85

Figure 6.9 Inferred impact zone based on monitoring of enterococci in the Water Quality Study during

June 2012. ............................................................................................................................................. 86

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1. INTRODUCTION

1.1 Objectives of Monitoring Program

The Burwood Beach Marine Environmental Assessment Program (MEAP) was implemented to

assess the spatial extent and ecological significance of impacts associated with discharge from the

Burwood Beach Wastewater Treatment Works (WWTW). The aims of the MEAP were to:

Establish the impact footprint of the existing outfalls;

Establish the gradient of impact with distance to the edge of the outfalls;

Discuss the broader ecological implications of any impact;

Extrapolate findings to make a judgment on the likely impact of future discharges; and

Assist in determining a long term strategy for treatment of wastewaters.

1.2 Objectives of the Integration Report

The purpose of the integration component of the MEAP is to provide an integrated environmental

assessment of the present and future discharges from the Burwood Beach WWTW to provide a basis

for the evaluation of environmental effects arising from future upgrades.

1.3 Outline of Report

The objectives of the MEAP and the integration component are outlined in this chapter, Chapter 1.

Chapter 2 is a summary of information on Burwood Beach WWTW including a plant description,

effluent and biosolid flows, existing effluent quality and nutrient and chemical loads. The outfalls

arrangement is provided as well as a summary of proposed options for future upgrades to Burwood

Beach WWTW.

A summary of the potential risks to the environment from wastewater disposal to ocean is provided in

Chapter 3. This chapter covers risks to toxicity, water quality, sediment quality, habitat,

bioaccumulation, human health and ecosystems.

Chapter 4 provides a summary of the MEAP key findings of the following study components and

summaries:

Physicochemical

o water quality (Section 4.2.1)

o marine sediment (Section 4.2.2)

Bio-chemical

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o Ecotoxicology (Section 4.2.3)

o Oyster bioaccumulation (Section 4.2.4)

o Seafood bioaccumulation (Section 4.2.5)

Biological

o Benthic reef communities (Section 4.2.7)

o Fish distribution (Section 4.2.8)

o Marine infauna communities (Section 4.2.9)

An overview of the integrated monitoring assessment is provided in Chapter 5 which outlines the

framework and decision criteria used to integrate the information from study components of the

MEAP.

Chapter 6 provides an environment impact assessment to bring together the study components of

the MEAP for an integrated environmental assessment of the present and future discharges from the

Burwood Beach WWTW to provide a basis for the evaluation of environmental effects arising from

future upgrades.

Conclusions of the integration task are provided in Chapter 7.

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2. BACKGROUND INFORMATION

2.1 Burwood Beach WWTW

The Burwood Beach Wastewater Treatment Works (WWTW) is located on the central coast region of

NSW approximately 2.5 km south of the city of Newcastle (Figure 2.1). The plant treats wastewater

from Newcastle and the surrounding suburbs, servicing approximately 185,000 people and local

industry. The secondary treatment process at Burwood Beach consists of physical screening to

remove large and fine particulates, biological filtration and activated sludge processing including

aeration and settling stages. Secondary treated effluent and waste activated sludge (biosolids) are

the by-products of the treatment process which are discharged to the ocean via separate outfalls.

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Figure 2.1. Location of Burwood Beach WWTW.

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2.2 Effluent and Biosolids Flows

2.2.1 Effluent and Biosolids Discharges

Flows from Burwood Beach WWTW represent a combination of secondary treated effluent flows,

biosolids flows and by-pass flows. On average total dry weather flow is 44 million litres of wastewater

(44 ML/d). Over the study period, the average flow was 57 ML/d which includes wet weather flows.

By the year 2040, these flows have been projected to increase to 54 ML/ d, even with water

conservation and recycling measures in place.

Bypass flow is effluent that bypasses secondary treatment and is discharged to the ocean. It receives

screening and degritting prior to discharge. This occurs when the amount of wastewater flow exceeds

the treatment plant capacity, usually following high rainfall events. During most months of the study,

there were bypass flows with a monthly average of 218 ML.

A summary of the monthly effluent and biosolids flow data from Burwood Beach WWTW during the

study period is provided in Table 2.1 and Figure 2.2. It can be seen that increasing monthly

secondary treatment flows and by-pass flows are associated with increasing rainfall. Peak total flows

are closely associated with peak periods of rainfall.

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Table 2.1 Effluent and biosolids flow data for the study period (July 2011 - May 2013).

Date

Rainfall (mm)

Secondary Flow (ML)

1

By-Pass Flow (ML)

2

Total Flow (ML)

Biosolids (ML)

3

July 2011 238.2 2068.14 777.24 2845.38 71.66

Aug 2011 47.8 1775.64 0 1775.64 87.73

Sep 2011 136.0 1731.62 205.9 1937.52 82.86

Oct 2011 161.4 1966.85 301.27 2268.12 94.93

Nov 2011 184.5 2004.51 465.58 2470.09 86.71

Dec 2011 110.8 1825.98 6.37 1832.35 92.83

Jan 2012 53.6 1481.64 22.32 1503.96 93.38

Feb 2012 336.7 2296.60 485.42 2782.02 89.47

Mar 2012 188.0 2083.66 403.74 2487.40 96.36

Apr 2012 174.0 1889.04 306.14 2195.18 88.98

May 2012 26.2 1470.51 0 1470.51 94.01

Jun 2012 188.0 2255.16 373.09 2628.25 95.01

Jul 2012 83.5 1839.45 24.17 1863.62 86.77

Aug 2012 71.0 1704.78 62.22 1767.00 93.44

Sep 2012 16.7 1305.15 0 1305.15 87.82

Oct 2012 13.5 1257.72 0 1257.72 76.17

Nov 2012 44.6 1201.80 0 1201.80 86.92

Dec 2012 114.2 1375.59 52.98 1428.57 98.06

Jan 2013 229.0 1488.58 322.25 1810.83 99.86

Feb 2013 175.0 1855.55 397.11 2252.66 87.39

Mar 2013 241.0 1954.00 629.58 2583.58 112.08

Apr 2013 94.5 1702.77 116.92 1819.69 102.98

May 2013 60.0 1538.14 55.7 1593.84 95.64

Monthly Average

(ML/ month) 129.92 1742.30 217.74 1960.04 91.35

Daily Average (ML/d) 4.26 57.12 7.14 64.26 3.00

1 Secondary Flow is total secondary treated flow through the plant (i.e. Total volume of screened and degritted

sewage into secondary plant over a 24 hour period from 12 midnight and discharged to ocean).

2 By-Pass Flow is total volume of screened and degritted sewage which bypasses the secondary plant over a 24

hour period from 12 midnight and is discharged to ocean

3 Biosolids is the Volume of Waste Activated Sludge pumped from the clarifier underflow over a 24 hour period

from 12 midnight and is discharged to ocean.

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Figure 2.2 Effluent and biosolids flow data for the study period (July 2011 – May 2013).

2.3 Existing Quality

The final treated effluent and biosolids from Burwood Beach WWTW has been monitored by Hunter

Water for physicochemical parameters, microbiological indicators of faecal contaminations and for a

suite of metals/metalloids and organic chemicals.

The median effluent quality from the Burwood Beach WWTW, based on extensive monitoring by

Hunter Water between 2006 and 2013, is summarized in Table 2.2 and the full suite of analytes

monitored are attached in Appendix 1. The table shows that median concentrations of nutrients

(ammonia, oxidised nitrogen, total nitrogen and total phosphorus) are very similar in effluent and

biosolids. In contrast, the suspended solids and biological oxygen demand (BOD) concentrations are

much higher in the biosolids, reflecting its high organic solids content. Concentrations of enterococci

and faecal coliforms are also much higher in the biosolids compared to the effluent. An estimated

concentration of selected parameters following dilution is also provided.

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Table 2.2 Effluent and Biosolids characteristics and estimated signature after dilution

Water Quality Parameter

Units Median

Level in Effluent

90% Level in Effluent

Median Level in

Biosolids

After Effluent Dilution

After Biosolids

Dilution

Ammonia mg N /L 23 29 24 0.128 0.120

Oxidised Nitrogen mg N /L 1.6 3.7 1.0 0.009 0.005

Total Nitrogen mg/L 28 38 29 0.156 0.145

Total Phosphorus mg/L 2.6 4.8 2.3 0.014 0.012

Suspended Solids mg/L 27 80 3,200 0.2 16

BOD mg/L 23 60 4,000 0.1 20

Salinity ppt 0.5 0.8 0.5 0.003 0.003

Enterococci CFU/ 100 mL 160,000 400,000 1,250,000 900 6,300

Faecal Coliforms CFU/ 100 mL 2,500,000 5,000,000 5,500,000 14,000 28,000

2.3.1 Nutrients

Nitrogen forms (ammonia, nitrites + nitrates, total kjeldhal nitrogen and total nitrogen) have been

routinely measured in effluent between 2006- 2013 with median (and range) concentrations of

23 mg/L (1- 33.1 mg/L), 1 mg/L (< 0.05- 14 mg/L), 26.9 mg/L (2.2- 48.7 mg/L) and 28.7 mg/L (2.45-

48.7 mg/L), respectively. Total phosphorus has been measured at a median concentration of

2.3 mg/L (0.09- 8.2 mg/L).

Ammonia is the only nutrient that has been measured in biosolids with a median concentration of 24

mg/L (0.01- 85.4 mg/L).

2.3.2 Chemicals

The metal/metalloid chemistry show that several elements are detected routinely in the monthly

sampling including silver, arsenic, chromium, copper, iron, mercury, manganese, nickel, lead,

selenium and zinc.

All organic chemistry data summarised from 2006 to 2013 demonstrated that for compounds including

organochlorine pesticides and polychlorinated biphenyls all results were below the limit of detection,

ranging from 0.001 to 0.01 µg/L, respectively.

2.3.3 Other Parameters

Suspended solids, UV254 nm transmittance (%T), total dissolved solids (TDS), biological oxygen

demand (BOD), chemical oxygen demand and grease are among other constituents that are routinely

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measured in effluent. Total solids, volatile solids and grease have been routinely measured in

biosolids.

The median suspended solids and BOD concentrations are very different in effluent and biosolids with

much higher levels in the biosolids reflecting the high organic solids content.

Microbiological parameters (such as faecal indicators enterococci and E. coli) have not been routinely

measured in effluent or biosolids from Burwood Beach WWTW but have been assessed, along with a

suite of pathogens, in a comprehensive study undertaken in 2010 by Roser et al. (2010) “Burwood

Beach Wastewater Treatment Plant Health Risk Microbial Risk Assessment Study (QMRA)”.

2.3.4 Loads of Constituents Discharges

The relative contributions of biosolids versus effluent for selected parameters are shown in Table 2.3.

This was calculated by multiplying the median levels in effluent or biosolids by the average daily flow

rate. The estimated load for biosolids was then divided by the estimated load in effluent to provide an

estimate of the partitioning of loads between the two streams.

It can be seen that biosolids has a much higher contribution to the total suspended solids loads. In

comparison, biosolids has a considerably lower contribution of 0.05 to the nutrient load (ammonia,

total nitrogen and total phosphorous) and contributes nearly half the total load for enterococci.

Table 2.3 Estimated ratio of biosolids to effluent for selected parameters

Loads Effluent Biosolids Biosolids: Effluent

Total suspended solids (mg/L) 1,889 13,507 7.1

Ammonia (mg N/L) 1,317 72 0.05

Total nitrogen (mg N/L) 1,603 87 0.05

Total phosphorus (mg/L) 149 7 0.05

Enterococci (CFU/ 100 mL) 9,159,515 3,751,893 0.41

2.4 Arrangements of Outfalls

Secondary treated effluent from Burwood Beach WWTW is discharged to the ocean through a multi-

port diffuser which extends 1,500 m offshore, with diffusers at a depth of approximately 22 m

(Figure’s 2.1 and 2.3). Biosolids, which are surplus to treatment requirements, are also discharged

to the ocean via a separate multi-port diffuser that extends 1,600 m offshore, with the diffuser at a

depth of 20 m.

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The seabed in the vicinity of the outfalls consists of small areas of low profile patchy reef, which is

subject to strong wave action and periodic sand movement, interspersed between large areas of soft

sediment habitat. These low profile reefs extend to approximately 1 m above the sand. Mobile sandy

sediments occur in the gutters and low-lying seabed between reef patches. Extensive sandy beaches

with intertidal rocky reef habitats occur along the shoreline adjacent to the outfalls. Merewether

Beach lies to the north and Dudley Beach to the south of Burwood Beach.

Both the effluent and biosolids outfalls have been operating in their current configuration since

January 1994.

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Figure 2.3. Burwood Beach WWTW and outfalls alignment.

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301020-03413 : Final Draft December 2013

2.5 Dilution Modeling / Dispersion Characteristics

Consulting Environmental Engineers (CEE 2007) calculated a predicted initial dilution for the

Burwood effluent outfalls, assuming a discharge rate of 43 ML/d and all duckbill valves in

operation. The model predicted a typical dilution of 219:1 for the effluent field. Allowing for the

reduction in dilution due to the orientation of the diffuser ports parallel to the currents, initial dilution

is expected to be in the range of 180:1 to 220:1. The Water Research Lab (WRL 2007) also

carried out field tests of effluent dilution using rhodamine dye. The dilution of the surface field

showed a typical dilution of 185:1. WRL (2007) reported that the average near-field dilution was

207:1 and the 95th percentile minimum dilution was 78:1. CEE (2010) therefore considers it

reasonable to base the environmental risk assessment of the effects of effluent discharge on an

effluent plume near the ocean surface with an initial dilution in the range of 100:1 to 200:1.

The dilution of a combined biosolids and effluent discharge through the biosolids diffuser was also

calculated (CEE 2007). The CEE model predicted a typical dilution of 475:1 for discharged

biosolids if they rose to the ocean surface, or about 250:1 if trapped by stratification at mid-depth

(CEE 2007). The WRL hydrodynamic computer model showed a median dilution of 300:1, with a

minimum dilution of 100:1 when strong stratification decreases the rise and dilution of the small

biosolids plumes, and a maximum dilution at times of strong currents exceeding 1,000:1 (WRL

2007). The WRL model also showed the biosolids plume is often trapped well below the surface

by the natural stratification of the ocean water column. WRL field tests of the biosolids plume, with

dilution measured using rhodamine dye, showed a typical dilution of 841:1. WRL reported that the

average near-field dilution of the biosolids plume was 268:1 and the 95th percentile minimum

dilution was 205:1, for a submerged plume (WRL 2007). Based on these results, it is considered

reasonable to base the assessment of the effects of biosolids discharge on two conditions; surface

plume with an initial dilution of 300:1 and submerged plume with an initial dilution of 200:1 (CEE

2010). WRL (1999) modelled the biosolids plume at 10 m depth and showed that the centre of the

plume, at about 10 m depth, the dilution achieved is between 200:1 and 1,000:1. At a distance of

200 m from the diffuser, the dilution exceeds 1,000:1 and increases further with distance travelled.

The diluted biosolids extends to the south of the diffuser, but would be indistinguishable except by

the sensitive techniques used in the field studies.

Previous diver inspections undertaken at the Burwood Beach outfalls (i.e. by commercial divers

inspecting the outfalls infrastructure) reported that biosolids deposits at the seabed can vary

significantly. In-situ diver observations have reported a biosolids thickness of 0 to 125 mm, with

variation likely a result of weather conditions. Divers have noted biosolids being washed away after

storms with no long-term accumulation on the seabed evident. More protected areas such as small

caves have a greater depth of biosolids and a peak of 400 mm was recorded in 1994/96 (note that at

this time effluent was not mixed with biosolids before discharge). ANSTO (1998) undertook a study of

the movement of seabed sediments 1,100 m south east of the outfalls using iridium-radiated glass

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beads. The beads were found to disperse over 100 m to the east and west and over 150 m to the

north, providing an indication of the likely expected movement of sandy sediments on the seabed. It

is expected that smaller biosolids particles would disperse at a greater rate and further than sand

particles.

2.6 Upgrades

Hunter Water is undertaking investigations into future treatment and disposal options for effluent and

biosolids at the Burwood Beach WWTW. Four potential scenarios have been selected by Hunter

Water for further consideration as provided in Table 2.1.

Table 2.4 Potential Upgrade Options. (Hunter Water 2013b).

Scenario Description

1 Biosolids to ocean, no nitrogen removal High rate activated sludge process

Biosolids discharge to ocean (current arrangement)

Effluent disinfection

2 Biosolids to land, no nitrogen removal High rate activated sludge process

Anaerobic digestion

Effluent disinfection

3 Biosolids to land, nitrogen removal Membrane Bioreactor (MBR) process

Aerobic digestion

Effluent Disinfection

4 Biosolids to ocean, nitrogen removal Membrane Bioreactor (MBR) process

Aerobic digestion

Biosolids discharge to ocean

Effluent Disinfection

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2.7 Receiving Environment

2.7.1 Metocean Conditions

CURRENTS AND T IDES

The region is broadly influenced by both the warm East Australian Current (EAC) from the north and

cool southern waters. Near shore there is often a complex current structure resulting from the

interaction of offshore currents, near shore retroflection and eddy currents, geologic features, weather

and, to a lesser extent, tides.

Tidal range is relatively small. At nearby Newcastle, the mean spring tidal range is 1.2 m and the

mean neap tidal range is 0.8 m (AusTides, Australian Hydrographic Service; www.hydro.gov.au).

UPWELLING

It is well established that the NSW coastline receives nutrient rich eddies from the East Australian

Current (EAC) (Suthers et al. 2011) and that upwellings of cold, nutrient rich bottom water are

common within the region. They can reduce surface water temperature by as much as 5°C and carry

high nutrient loads, particularly nitrates, into the euphotic zone (Oke and Griffin 2011; Suthers et al.,

2011). These nutrients are important in the enrichment of local coastal ecosystems and stimulate high

phytoplankton productivity (Dela-Cruz et al., 2008). The nutrient load derived from upwellings far

exceeds nutrient loads delivered by either river or sewage discharges (Pritchard et al., 2003).

Wind-driven upwelling occurs in response to north and northeasterly wind, typically over summer.

They are generally confined to the coastal zone, localised and short-lived (Roughan and Middleton

2002).

Local changes in coastal bathymetry are thought to predispose certain areas, including Port

Stephens, Newcastle, Port Hacking to Wollongong and Jervis Bay, to EAC induced slope water

intrusions (Lee et al. 2001). To the north of Port Stephens, the continental shelf narrows significantly,

causing acceleration of the East Australian Current (EAC). The main flow of the EAC is known to

separate from the NSW coast at Port Stephens, which is approximately 25 km north-east of

Newcastle. The coastal circulation north of Port Stephens is dominated by a southward flowing EAC

that is highly energetic, flowing with currents of 2 m s-1

. Further upwelling is driven by cross-shelf

boundary layer fluxes and eddy currents associated with the EAC’s separation from the coast.

Topographic variations near Laurieton (north of Port Stephens) are thought to create high bottom

stress that drives the EAC down the coast to Port Stephens where it then upwells and separates from

the coast. Instability along the front of the warm EAC current and the colder Tasman sea has been

shown to often lead to the formation of large (~150 km) warm core anticyclonic eddies and smaller

(20 - 50 km) cyclonic eddies that may persist for days to many weeks at a time (Cresswell and

http://www.hydro.gov.au/

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Legeckis 1986; Pritchard et al. 2001). Separations of the EAC along the north coast of NSW have

been shown to correspond with high levels of chlorophyll-a mass along the shelf (Tranter et al. 1986).

These periods of upwelling have been found to be seasonal (peaking during summer/spring)

(Pritchard et al. 1998). During January - March 2012, the website for the Integrated Marine

Observing System (IMOS) reported that there was a cyclonic eddy upwelling of deeper and cooler

waters from the continental shelf in coastal waters from Sydney to Bryon Bay (IMOS 2012). This is

the only reported upwelling event during the MEAP study period, although it is possible that other

occurred. At other times when variables exceed the guidelines with a similar magnitude across

spatial sites, this could be due to upwelling events. Elevated values could also potentially be due to

alternative sources of nutrients, such as terrestrial runoff, or other natural processes such as ocean

swell.

WAVES

Burwood Beach faces south-east and is exposed to waves and prevailing south-easterly swell from

the Pacific Ocean. Swell is generally between 0.5 m and 2 m in height, but regularly exceeds 3 m,

particularly during winter storms. This high energy environment has a significant role in the dispersal

of wastewater discharges. Large swells can drive mixing of the water column to depths >20 m and

resuspend settled particulate material.

The high energy wave climate causes intermittent sand movement over the low profile subtidal reefs

at Burwood Beach. The low profile reefs are periodically inundated by sand, which is likely to be a

major impediment to development of reef flora and fauna. Frequent smothering means the reef areas

are unlikely to be able to maintain stable flora and fauna communities, with assemblages dominated

by pioneer species.

The resuspension of sediments by wave action can substantially increase light attenuation in the

water column. Light availability is a key determinant of the distribution of algae and reduced light

penetration is likely to limit many algal species to shallower reefs in the area.

W INDS

Averaged wind data was available from Nobbys Head, Newcastle, 6.7 km northeast of Burwood

Beach, from Jan 1957 to Sep 2010 (Bureau of Meteorology;

http://www.bom.gov.au/climate/averages/tables/cw_061055.shtml).

Between January to March 2007, WRL undertook analysis of the recorded winds from Newcastle

Nobby’s Station and overlaid this data with oceanic currents (2007). This data showed that during

the study, the oceanic currents were strongly affected by wind speed and wind direction at all depths.

The currents also displayed a clear tidal influence. Vector stick plots of wind, current direction and

temperature over depth that were generated by WRL (2007) are attached in Appendix 2.

http://www.bom.gov.au/climate/averages/tables/cw_061055.shtml

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There are diurnal and seasonal patterns in prevailing wind direction. During winter, the prevailing wind

blows offshore, from the northwest. During spring and autumn, prevailing winds are from the

northwest in the morning and easterly to southerly in the afternoon. In mid to late summer, prevailing

winds are southerly in the morning, and easterly in the afternoon.

Winds are generally stronger in the afternoon (monthly mean 3 pm wind speeds between 25 and 35

km/hr) compared to the morning (monthly mean 9 am wind speeds between 20 and 25 km/hr).

TEMPERATURE

The mean ocean surface temperature at Newcastle is 20.24°C. There is a small seasonal range of

5°C, with the lowest monthly average (18°C), in August and highest (23°C) in March (Table 2.5).

As the region is unevenly influenced by the East Australian Current and upwelling events, water

temperature can vary by as much as 5°C on relatively small temporal and spatial scales. Southerly

winds will generally push warmer waters associated with the EAC closer to shore, while winds from

the north and north-east will uplift colder bottom water along the coast.

Table 2.5. Mean Monthly Surface Seawater Temperature (°C) for Newcastle

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

22.0 22.4 22.7 21.6 20.3 19.3 18.2 17.8 18.5 19 20.2 20.9

Source: Royal Australian Navy Meteorology and Oceanography Service (METOC) http://www.metoc.gov.au/

Analysis of oceanic temperature in the Burwood Beach receiving waters was undertaken by WRL

(2007) between January to March 2007. This showed that during the warmer waters, there was

thermal stratification to various extents. This was particularly apparent during 16th - 24

th February

when there was a 4°C difference between 5 m and 20 m. Stratification appeared to coincide with

easterly winds but it was noted by WRL (2007) that this was not always the case. These results are

attached in Appendix 2.

2.7.2 Beach Water Quality

Hunter Water monitors enterococci bacteria at seven beaches in the Newcastle area as part of the

NSW Beachwatch Partnership Program. Two sites are directly adjacent to the Burwood Beach

WWTW: Burwood South Beach and Burwood North Beach. These sites have been monitored since

1996 and microbial water quality has generally been of a high standard, with most (>90%) of

measurements having very low levels of indicator bacteria (≤40 cfu/100mL). The enterococci levels

http://www.metoc.gov.au/

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increase slightly in response to rainfall, but mostly remain below the safe swimming limit (Department

of Environment and Heritage 2013; http://www.environment.nsw.gov.au/beach/ar1112/).

Coastal waters in the vicinity of Newcastle are regularly nutrient enriched by upwelling bottom waters.

This is recognized in the ANZECC/ARMCANZ Guidelines (2000), which sets a higher limit for marine

nitrogen in New South Wales. However, concentrations may still naturally approach or exceed these

limits. The elevated nutrients and cooler waters associated with upwelling are known to promote

phytoplankton blooms, which may further reduce water quality by reducing dissolved oxygen,

increasing turbidity and, in some cases, producing toxins.

The Hunter River discharges to the Pacific Ocean approximately 7 km northeast of Burwood Beach

and Flaggy Creek discharges via Glenrock Lagoon 500 m south of Burwood Beach WWTW.

Following rainfall, increases in urban stormwater runoff into these waterways and to Merewether and

Bar ocean beaches, are likely to contribute to variability in water quality.

2.7.3 Sediment Quality

The Hunter Environmental Monitoring Program (Hunter EMP) was designed and undertaken by the

EPA between 1992 and 1996 to investigate contaminant concentrations in the marine environment of

the Hunter Region. The Hunter EMP included an investigation of contaminants in sediments. The

sediment study involved biannual collection of sediment cores at “putative impact” and “control”

locations using divers. Putative impact locations included the Boulder Bay outfalls, Burwood Beach

outfalls, Belmont Beach outfalls, Newcastle Harbour entrance and Newcastle dredge spoil ground.

Control locations included Port Stephens, Boat Harbour, Cemetery Point and Redhead. Sediment

samples were tested for a range of organochlorines and trace metals, fine particle content and TOC

(NSW EPA 1995, 1996).

Of the seventeen organochlorines that were tested, only six (including technical chlordane, dieldrin,

dichlorodiphenyltrichloroethane (DDT), dichlorodiphenyldichloroethane (DDD),

dichlordiphenyldichloroethylene (DDE) and polychlorinated biphenyls (PCBs) were detected in

sediments across the sampling period, with the majority of samples returning a “not detected” or trace

result. As a result, the calculated mean concentration for all organochlorines tested was below the

analytical limit of detection (with the exception of technical chlordane and DDD (NSW EPA 1995,

1996).

The concentrations of most trace metals at most locations were highly variable through time, and

there was no obvious elevation of contaminant concentrations at most locations (NSW EPA 1995,

1996). Trace metal concentrations at Burwood Beach were low and comparable to those found in

earlier studies undertaken for the Sydney ocean outfalls. Sediment at the nearby Newcastle Harbour

entrance and dredge spoil ground had significantly higher concentrations of trace metals, particularly

zinc, lead and manganese, compared to control locations. The mean concentrations of all trace

http://www.environment.nsw.gov.au/beach/ar1112/

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metals, with the exception of manganese in three of 466 samples, was below the concentration

considered to have adverse biological effects (NSW EPA 1996).

A decade later, BioAnalysis (2007) sampled sediments at the Burwood Beach outfalls and multiple

reference locations in order to determine whether there were any impacts of contaminants associated

with discharge of the effluent and biosolids. A nested sampling design was used; at each location two

random sites were sampled and within each site three replicate samples were taken. Samples were

analysed for a range of contaminants including organochlorine pesticides (OCs), trace metals,

nutrients, endocrine disrupting compounds (EDCs) and sediment characteristics.

There was a significantly higher proportion of fine sediments close to the outfalls. However, there

were no significant patterns to show that contaminants were accumulating in sediments associated

with the outfalls. No OCs or EDCs were detected in sediments at the outfalls or reference locations

and concentrations of trace metals were all below the relevant ANZECC/ARMCANZ Guidelines

(2000) for sediment quality and were consistent with previous studies. Levels of trace metals were

more elevated at the reference than outfalls locations (with the exception of manganese) and there

were no distinct patterns in concentrations of general chemicals within sediments associated with the

outfalls (BioAnalysis 2007). Metal concentrations were similar to those measured previously by the

NSW EPA (1995).

2.7.4 Nearby Potential Pollutant Sources

The Burwood Beach WWTW is located seven km south-west of the entrance to the Hunter River.

The Hunter River catchment is one of the largest in NSW and covers an area of approximately

22, 000 km2 (MHL, 2003). The Hunter River is approximately 300 km long and originates in the

Mount Royal Range and enters the sea at Newcastle. The median flow rate of the Hunter River is

approximately 380 ML/d.

Tidal flushing of the Hunter River is likely to influence the water quality around the mouth of the river

and contribute to nutrient loads (such as nitrogen and phosphorus) into the ocean. A qualitative

spatial assessment of water quality has been previously undertaken using a compilation of data

collected by Hunter Water, NSW EPA and Maitland City Council (Sanderson and Redden 2001). This

study suggested a weak source of phosphorus between Raymond Terrace and Morpeth. Dissolved

inorganic nitrogen (DIN) was found to be distributed throughout the lower reaches of the river.

Chlorophyll-a concentrations were found to be high in the upstream reaches of the river and but

decrease towards the mouth. Dissolved oxygen levels were generally quite good but increased

slightly downstream. In high flows the river becomes almost fresh with brackish water near the

mouth.

The Hunter River catchment is also highly urbanised. The city of Newcastle is located close to the

mouth of the Hunter River and is NSW’s second largest city. Newcastle Harbour is highly

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industrialised and is a large coal export terminal. The Williams River flows into the Hunter River and

this catchment is characterised by rural land use with pockets of intensive agriculture such as poultry

and dairy farms. Urban and industrial runoff in the Hunter River catchment is a potential source of

metals, hydrocarbons, oils, bacteria, nutrients and other chemicals (i.e. such as pesticides).

The transport and spatial extent of chemical and nutrient loads from the Hunter River have not been

well characterised but it is possible that it extends to the receiving waters of Burwood Beach WWTW

or beaches to the north (i.e. Merewether). Any influences from the Hunter Water would be affected

by rainfall, particularly during high rain events which flush the catchment.

Glenrock lagoon is a freshwater small coastal creek which is located adjacent to Burwood Beach and

to the south. This lagoon has an average depth of 2.4 m and draws its catchment from Flaggy Creek

with a catchment area of 7.4 km2. It is located in a State Recreational Area so is largely undisturbed

by human activities. It is possible that flushing of Glenrock Lagoon contributes to natural levels of

nutrients and possibly bacteria levels (i.e. from animals) in the nearby ocean waters.

2.7.5 Surrounding Marine Habitats

Under the Integrated Marine and Coastal Regionalisation of Australia (IMCRA version 4.0, 2006;

http://www.environment.gov.au/coasts/mbp/imcra/), Burwood Beach sits within the Hawkesbury Shelf

Bioregion. Within this bioregion, Burwood Beach is in the Hunter – Lake Macquarie unit area (Breen

et al., 2004). This area contains the following habitat types:

Estuary – Hunter River, a wave dominated barrier estuary

Intertidal rocky shore - platform, crevice, pool and boulder habitats

Beach – reflective and intermediate grade beaches

Island – islands and rocks within 1 km of the mainland

Shallow subtidal reef – bedrock, crevice and boulder habitats

Shallow subtidal sediment – predominantly medium to coarse grained quartzose sands

Extensive sandy beaches with intermittent intertidal rock platform habitats occur along the shoreline

adjacent to the outfalls.

Water depth is approximately 22 m at the outfalls’ diffusers. The seabed consists of small areas of

patchy rocky reef, interspersed between large areas of soft sediment (sandy) habitat. The reef is

predominantly low profile, extending approximately 1 m above the sand. Directly inshore of the

diffuser is an patch of higher relief with ledges, overhangs and crevices. The reef areas are subject to

strong wave action and periodic sand inundation, particularly on low profile reefs. Suspended

sediments significantly attenuate light penetration through the water column and limited light

availability is likely to restrict most algal to shallower reefs in the area.

http://www.environment.gov.au/coasts/mbp/imcra/

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Fine mobile sandy sediments occur in reef gutters and more extensive areas on low-lying seabed

between reef patches.

Sessile invertebrates are the most diverse and abundant assemblage on subtidal reefs at Burwood

Beach (BioAnalysis 2006). The benthic invertebrate fauna recorded at the Burwood Beach outfalls

and surrounding reefs was dominated by porifera (sponges), followed by cnidarians (sea anemones,

corals and sea pens), echinoderms (feather stars, sea stars and brittle stars) and ascidians (sea

squirts). Bryozoans (moss animals) and molluscs are low in abundance and absent from the majority

of sites. Passion feather stars (Ptilometra australis) are very abundant on low profile reefs in the area,

but not present on the higher reef at the outfalls.

Fish assemblages on these reefs include resident species like small scale bullseye (Pemphris

compressa), white ear damselfish (Parma microlepis), southern Maori wrasse (Ophthalmolepis

lineolatus) and morwong (Cheilodactylus fuscus and C. spectabilis). Very high abundances of the

yellowtail (Trachurus novaehollandiae) are usually present at the diffuser. Other transient species

common on the reefs include breams (Acanthopagrus australis and Rhabdosargus sarba) and silver

sweep (Scorpis lineolatus). Flathead (Platycephalus spp.) and goatfish (Upeneichthys lineatus) are

common on soft sediments.

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3. ENVIRONMENT QUALITY ASSESSMENT

The National Water Quality Management Strategy (NWQMS) recommends an integrated approach to

protect biota in the receiving waters from sustained exposures to toxicants which incorporates:

Monitoring of individual constituents of concern and comparison to guidelines;

Direct toxicity assessments (DTAs); and

Biological Monitoring.

3.1 Water Quality

The discharge of wastewaters has the potential to impact on local water quality. Potential risks

include changes to the physicochemistry, elevated levels of nutrients or elevated levels of faecal

indicators.

Changes in water quality conditions around the outfalls and diffusers may affect aquatic organisms.

These changes can include reduced water clarity and light penetration resulting from particulates or

colloidal matter, reduced salinity due to the freshwater nature of the discharges and reduced

dissolved oxygen as a consequence of the biological transformation of the organic matter and

nutrients in the discharges.

One challenge in water quality monitoring is being able to differentiate between an event related to

the outfall discharge and natural/alternative sources of nutrients. Elevated values of nutrients could

also potentially be due to alternative sources, such as terrestrial runoff, or other natural processes

such as upwelling events.

A high level of beach water quality is important to maintain the aesthetic appeal of the water body and

so that communities are able to use water bodies for recreational activities, such as swimming and

boating, without a significant health risk.

3.2 Sediment Quality Benthic sediments have the potential to act as a sink for chemicals that are released in wastewaters,

particularly since many chemicals have a high affinity for sediment particles. Chemicals that may be

expected to accumulate in sediments includes metals/metalloids and organic chemicals (such as

organochlorines [OCs], organophosphates [OPs] and polychlorinated biphenyls [PCBs]). Total

organic carbon (TOC) may also accumulate in sediments due to discharge of wastewaters,

particularly in the case of biosolids.

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Sediment size is an important measure that needs to be included in assessments of metals and

metalloids in sediments whereby concentrations in sediments around an outfall are being compared

to reference locations. Metals and metalloids and TOC show a strong association with finer particles

and so particle size needs to be accounted for in analysis.

Metals/metalloids and total organic carbon are natural constituents of the environment so any

evaluation of impacts from WWTWs needs to take background levels into consideration (i.e. through

comparison to samples from appropriate reference locations).

3.3 Toxicity

Wastewaters are mixtures and likely contain a wide suite of nutrients, chemicals and other

constituents. Following release into the aquatic environment, marine biota may be exposed to

wastewater constituents through direct ingestion of water, particulates or food sources or via contact

with their skin. One concern associated with uptake by aquatic biota is the potential toxicity effects

which can include reproductive and growth impairments, behavioural abnormalities and in some

cases, mortality. The extent of this toxicity is dependent on the summation of the toxicity of individual

components that make up the composition of the wastewaters. This is likely to vary temporally

dependent on what is entering the wastewater stream and their concentrations.

Routine monitoring should be undertaken to ensure that discharge of wastewaters does not affect the

growth, survival or reproduction of aquatic species. Direct Toxicity Assessments (DTAs) are standard

chronic or acute tests that have been developed to determine the toxicity of single chemical exposure

or mixtures (i.e. such as effluent) to standardized endpoints on appropriate, usually local, species.

Endpoints that are commonly tested include growth, fecundity, fertilisation, larval or embryonic

development and mortality. As stated in ANZECC (2000), the minimum requirements for DTA

(Section 8.3.6.8) recommend that toxicity data from between three to five species is required for

effluent DTA and should cover a range of trophic levels. It is also recommended that the range of

DTA tests include both acute and chronic tests.

Wastewaters are a complex mixture of many individual constituents. In terms of measuring toxicity,

one advantage of DTA is that it is an integrated measure and takes into account the overall toxicity of

the mixture on the endpoint tested. However one limitation of DTAs on complex mixtures such as

wastewaters is that can be difficult to identify which constituents in complex mixtures are responsible

for any observed toxicity. Toxicity Identification Evaluations (TIEs) are methods that have been

developed to identify what components are responsible for causing toxicity. This involves

manipulating and fractionating the test substance and conducting additional DTAs to separate the

toxic components.

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3.4 Bioaccumulation

Oceanic discharge of sewage effluent and biosolids is of concern due to the potential risk of

chemicals entering the marine environment. Some chemicals have a potential to bioaccumulate in

marine biota. Bioaccumulation is the net product of uptake, metabolism and excretion of chemicals.

Examples of chemicals that are known to bioaccumulate include metals/metalloids, polychlorinated

biphenyls (PCBs), organochlorines (OC) pesticides and organophosphorus (OP) pesticides.

Direct measurements of metals/metalloids, PCBs and pesticides in seawater or sediments can

sometimes pose difficulties. Chemicals in seawater are often at low concentrations, below limits of

analytical detection. Another consideration is that release of chemicals is not constant but instead

likely to be dependent on pulse releases into the aquatic environment. Biomonitoring overcomes this

issue. Biomonitoring is the use of organisms which accumulate contaminants and reflect their

environment making them suitable to assess the health of the ecosystem. One form of biomonitoring

is measurement of the bioaccumulation of chemicals in biota that reside within the ecosystem. Where

chemicals are elevated (in comparison to suitable reference locations) in biomonitoring studies, this

can indicate the presence of elevated chemicals in their tissues (i.e. bioaccumulation). Assessment

of microbial indicators of contamination is another useful form of biomonitoring.

Fish are considered useful for bioaccumulation studies due to the fact that they have a relatively large

body size and long life cycle and many species spend their lifetime in one region. They are located at

the top of the food chain and so are useful for biomonitoring of chemicals that have potential to

biomagnify. The bioaccumulation of chemicals in their tissue may directly affect human health.

Molluscs, in particular oysters, have been established to be highly useful as biomonitors of

metals/metalloids with a demonstrated capacity to bioaccumulate metals/metalloids, which reflect

environmental concentrations. In Australia, S. glomerata, is commonly used for biomonitoring of

heavy metals/metalloids in the marine environment. Molluscs are also considered to be effective

biomonitors of organic chemicals in the aquatic environment, although in Australia this has been

studied to a much lesser extent compared to oyster biomonitoring of metals/metalloids due to the high

lipid content in oysters which is known to interfere with organic chemical analyses.

3.5 Human Health

The discharge of wastewaters is of potential concern to human health, particularly in relation to

exposure to pathogens. There are several pathways whereby humans could be exposed:

Direct exposure in bathing or recreational waters; or

Consumption of seafood which is contaminated by pathogens or chemicals.

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Faecal coliforms and enterococci have been used as indicators of faecal contamination in the

receiving environment of WWTWs to assess this risk. Enterococci are considered to be the preferred

indicator for marine waters by NSW EPA (2000).

The assessment of microbial indicators in the edible tissue of seafood is useful to indicate microbial

contamination from sewage (Australian and New Zealand National Food Authority; ANZFA 2001).

Common indicators include thermotolerant faecal coliforms, E. coli, Salmonella sp. and enterococci.

Effluent and biosolids may also be examined to determine the microbial communities to predict risks

of discharge to the community.

3.6 Habitat and Ecosystem The change in ecosystem represents an integrated response to the combined effects of the biosolids

discharge, the effluent discharge and all other environmental stressors. By combining the physical,

biochemical and biological evidence of change, an overall assessment of environmental impact can

be determined.

The release of sewage into the marine environment has been demonstrated to impact on marine

biota at the cellular, individual and community levels (Underwood and Peterson 1988). The type and

extent of impact varies and depends on the quantity and composition of sewage effluent, the dilution

and the frequency and duration of exposure. Impacts on marine biota have been reported as

localised, in the immediate vicinity of the WWTW or wide ranging, such as kilometres from the

WWTW source. Temporally, impacts may be pulse events or sustained press events (Underwood

1992, 1993).

Observations of marine organisms that live on or in the receiving environment of a WWTW are useful

to determine the integrated response. Some potential responses of marine biota and communities to

the discharge of wastewaters could include changes in communities or in the abundance, diversity or

richness of communities or individual taxa. This could manifest in terms of:

Stimulation of marine communities in response to additional nutrient loads;

Suppression of marine communities in response to contaminant loads or toxicity;

Suppression of marine communities due to smothering (i.e. from biosolids) or reduced light

penetration;

Changes in marine communities due to a freshwater effect;

Increased proportion of opportunistic species;

Decreased abundance of sensitive species; and

Change in marine communities due to competition for habitat.

Common marine communities that have been used to monitor for the impacts of WWTWs include fish,

infauna, reef algal and reef fauna.

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Sewage effluent discharge has been shown to affect the diversity, abundance, mortality and fecundity

of fish, causing increased susceptibility to infection and parasitic invasion. Some studies have

reported a negative relationship between fish assemblage attributes (e.g. abundance, richness and

diversity) and / or populations and sewage outfalls. In comparison, other studies have found that fish

abundance and diversity may be higher at sewage outfalls in comparison to reference locations.

These patterns have been attributed to localised nutrient enrichment caused by sewage effluent

discharge, resulting in a higher density of plankton and suspended organic matter (i.e. fish food) in

the receiving environment of WWTW’s. Effects of sewage outfalls on fish assemblages may vary

temporally and spatially highlighting that programs need to have appropriate replication to account for

this.

Soft sediments provide habitat for a range of macroinvertebrate infauna (i.e. fauna living within the

sediments) including crustaceans (amphipods, isopods and cumaceans), worms (polychaetes,

nemerteans) and molluscs (bivalves and gastropods). Marine infauna assemblages have been used

extensively to monitor the level of anthropogenic impacts on the marine environment. Infauna

assemblages are useful as indicators due to their relatively sedentary lifestyle and as they live within

the sediments. Environmental changes, resulting from the discharge of treated sewage effluent into

the marine environment, can include increased algal growth as a result of increased availability of

nutrients (e.g. phosphorus and nitrogen), release of and potential exposure to organic and / or

inorganic contaminants and pathogens (bacteria or fungi) from wastewater. In turn, impacts on

infauna communities can include changes in species abundance, species richness, the dominance of

opportunistic species or the dominance of deposit feeders. Changes in infauna communities around

the point of WWTW effluent and/or biosolids discharge may result from organic enrichment of bottom

sediments. Organic and inorganic contaminants in sewage can also bioaccumulate in soft-bottom

organisms causing alterations to infauna communities. One of the difficulties in using infauna

assemblages to monitor impacts of WWTWs is their inherent spatial and temporal variability, making it

difficult to attribute change to an impact rather than natural variation. Infauna communities are

composed of a mosaic of successional patches, resulting from numerous interacting processes; also

attributing to the significant spatial and temporal variation observed.

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4. MONITORING PROGRAM

4.1 Overview of MEAP

4.1.1 Development

The MEAP was developed following the concepts and monitoring frameworks set out in the Australian

and New Zealand Guidelines for Fresh and Marine Water Quality (ANZECC/ARMCANZ, 2000), the

MEAP uses a multidisciplinary monitoring approach that incorporates a mix of complementary

physical, chemical and biological indicators to assess the overall effect of wastewater discharges on

the ecological health of the marine ecosystem.

The use of a combination of biological, bio-chemical and physicochemical assessments enhances the

confidence in correctly attributing causes to any observed patterns: biological indicators directly

assess the effects of the outfalls on the ecosystem, while physicochemical indicators may provide

explanation for any biological patterns observed. The MEAP was developed to be aligned with

aligned with environmental risks to the marine environment that are generally associated with

WWTWs. Study components included:

Physicochemical

o water quality

o marine sediment

Bio-chemical

o oyster bioaccumulation

o seafood bioaccumulation

o Direct Toxicity Assessment

Biological

o benthic reef communities

o fish distribution

o marine infauna communities

4.1.2 Consultation

Prior to commencement of the Burwood Beach MEAP, details of the proposed sampling program and

survey methodology were discussed with Hunter Water, CEE and the NSW EPA (then the Office of

Environment and Heritage, OEH) on 10 October 2011. This initial consultation was undertaken to

ensure that the proposed MEAP was adequate in addressing the requirements of both the Client and

the Regulator. During this meeting, concerns with the proposed survey / sampling program were

raised and where required the methodology was subsequently altered accordingly.

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Consultation was also undertaken with the NSW Marine Parks Authority (Port Stephens) regarding

the MEAP, in particular the Burwood Beach Fish Distribution Study. At their suggestion, the baited

underwater remote video survey (BRUVS) method was incorporated into the study to expand the data

set.

Prior to deployment of the mooring systems for the Oyster Biomonitoring Study at Burwood Beach,

the Newcastle Fishing Co-operative and NSW Fisheries were consulted to identify any concerns

related to commercial fishing operations within the study area. The Newcastle Ports Corporation

(NPC) was also consulted to identify any issues associated with commercial shipping and as a result

the size of marker buoys was increased to make them more visible.

The NSW EPA and NSW Health Authority were consulted extensively during 2011 and 2012 to

identify the appropriate analytes for the Seafood Bioaccumulation Study. The fish species sampled in

this study were determined through consultation with the Newcastle Fisherman’s co-operative, local

fishing charter operators and local commercial fisherman, to identify the species which are commonly

collected and consumed from Burwood Beach and surrounding areas.

4.1.3 Previous studies/ limitations

A number of monitoring programs and studies have previously been undertaken to assess the impact

of treated effluent and biosolids discharge on the marine environment at Burwood Beach (e.g. NSW

Environment Protection Authority (EPA) 1994, 1996; The Ecology Lab 1996, 1998; Australian Water

Technologies (AWT) 1996, 1998, 200, 2003; Sinclair Knight Merz (SKM) 1999, 2000; Ecotox Services

Australasia (ESA) 2001, 2005; BioAnalysis 2006; Andrew-Priestley 2011; Andrew-Priestley et al.

2012). While providing a wealth of data on the receiving marine environment, it is considered that

these previous studies have not effectively assessed the spatial extent and ecological significance of

impact associated with the discharge from the outfalls (CEE 2010).

4.1.4 Design

As the Burwood Beach wastewater treatment works (WWTW) was already in operation for many

years prior to the establishment of the MEAP, it was not feasible to implement a ‘before–after’ type

sampling design. Instead the MEAP draws inferences about impact by way of assessing disturbance

along spatial gradients.

4.1.5 Implementation

The MEAP was implemented over a 2 year period, commencing in June 2011 and concluding in

September 2013. The Water Quality Study was undertaken between July 2011 and April 2013, with

eight sampling events occurring every 3 months. The sediment study had two sampling events, with

sediments collected in December 2011 and October 2012. In the Marine Ecotoxicology Study, there

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were six sampling events with quarterly sampling in the first year and biannual sampling in the second

year. The Seafood Bioaccumulation Study was undertaken in 2013 with three sampling events

occurring in February 2013, March 2013 and April 2013. Supplementary seafood resting was

undertaken in September 2013. All other studies, including oyster bioaccumulation, benthic reef

communities, fish distribution and marine infauna communities, were undertaken over two years and

in four sampling events which occurred every six months.

4.2 Component Studies and Impacts

4.2.1 Water Quality

The Burwood Beach Water Quality Study was undertaken to characterise the extent of impacts on the

receiving environment from effluent and waste activated sludge (biosolids) discharges and to define

the near, mid and farfield impacts of the effluent and biosolids plume. The primary objectives of the

water quality monitoring study were to:

Measure physicochemistry parameters and concentrations of nutrients, chlorophyll a and faecal

indicators in the receiving environment, at a range of distances from the outfalls, to assess

the gradient of potential impact;

Compare data with relevant guidelines to identify compliance (where applicable). This includes

the Australian and New Zealand Environment and Conservation Council (ANZECC)

Guidelines for Fresh and Marine Water Quality (2000), the New South Wales Environmental

Protection Authority (NSW EPA) Marine Water Quality Guidelines (2000) and the National

Health and Medical Research Council (NHMRC) Guidelines for Managing Risks in

Recreational Waters (2008); and

Establish the footprint of impact on the receiving environment.

Water sampling was undertaken at 32 sites, which were selected in a regularly spaced radial

arrangement around the outfalls diffusers (at distances of 0 m, 30 m, 100 m, 250 m, 500 m and 2 km).

The location of sampling sites took into account the locations of the effluent and biosolids outfalls,

prevailing hydrodynamic conditions in the area and plume characteristics. For some summaries, the

distances were also divided into three zones which included the outfalls zone (0 and 30 m), the

mixing zone (100, 250 and 500 m) and the reference zone (2 km).

A suite of parameters, including physicochemical, nutrients, chlorophyll a and faecal indicators, were

measured at each site (Table 4.1). Measurements of physicochemistry and chemistry sampling were

undertaken at two depths (surface and mid-water). A total of 64 water column samples were collected

during each sampling event to test for nutrients, chlorophyll a and faecal indicators (i.e. 32 sites x 2

depths).

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Table 4.1 Analytical parameters showing their respective LOR and guideline values.

Analytical Parameter Limit of Reporting

(LOR)

Guideline Guideline reference

In-situ physico-chemical

Secchi-disc depth 0.5 m 1.6 m NSW EPA (2000); ANZECC (2000)

Turbidity 0.1 NTU 6 NTU ANZECC (2000)

Temperature 0.01 °C 15-35 °C NSW EPA (2000)

Electrical Conductivity 0.01 mS/cm None defined

Salinity 0.01 ppt None defined

Dissolved Oxygen mg/L None defined (in mg/L) 6

pH 0.1 8 - 8.4 ANZECC (2000)

Nutrients

Organic Nitrogen as N 5 0.01 mg/L None defined

Ammonia as N 0.005 mg/L 0.02 mg/L

0.91 mg/L7

ANZECC (2000)

ANZECC (2000)

Nitrite + Nitrate (NOx) 0.002 mg/L 0.025 mg/L ANZECC (2000)

Dissolved Inorganic Nitrogen (NH3 + NOx)

3 0.005 mg/L None defined

Total Nitrogen as N 4, 5

0.01 mg/L 0.12 mg/L

NSW EPA (2000); ANZECC (2000)

Total Phosphorus as P 0.005 mg/L 0.025 mg/L NSW EPA (2000); ANZECC (2000)

Chlorophyll a 1 0.5 mg/m

3 (i.e. 0.5

µg/L) 1 mg/m

3 ANZECC (2000)

Thermotolerant Faecal Coliforms 2, 9

1 CFU/100 mL 50% of values ≤150 CFU/100 mL

ANZECC (2000)

Enterococci 2, 8

1 CFU/100 mL 95th percentile of values ≤40 CFU/100 mL

NHMRC (2008)

1 Note that an LOR of 1 mg/m

3 was used for chlorophyll a for the first two sampling events, as per the original agreement

between WorleyParsons, the analytical laboratory and Hunter Water. This LOR was subsequently changed to 0.5 mg/m3.

2 Note that for turbid water samples the analytical laboratory advised that the LOR for microbial samples may need to increase

to 2 CFU / 100 ml. This would be based on visual inspection at the laboratory and cannot be based on any predetermined turbidity value.

3 Dissolved parameters (i.e. dissolved inorganic nitrogen) required field filtering.

4 Note that total nitrogen is calculated by the laboratory as a separate analysis and is not determined by calculation (i.e. may

not always equal the sum of nitrogen components as provided in the data). 5 Note that an LOR of 0.05 mg/L

was used for organic nitrogen and total nitrogen for the first two sampling events, this LOR was

subsequently changed to 0.01 mg/L in later sampling rounds. 6 ANZECC Guideline for dissolved oxygen is 90 to 110 % saturation; however dissolved oxygen was measured in mg/L in this

study. 7 Note this refers to ANZECC (2000) default trigger value for ammonia for 95% level of protection of species in marine waters.

8 Note that ANZECC refers to NHMRC 2008 “Guidelines for Managing Risks in Recreational Waters”. These NHMRC Guidelines recommend a 95 % enterococci limit of < 40 cfu/100 mL as this value is below the NOAEL in most epidemiological studies and the AFRI would be negligible. 9 Note that Faecal coliforms are considered by the NHMRC as an unsuitable regulatory parameter but still form part of NSW Water Quality Guidelines with the limit being 50 % < 150 cfu/100 mL.

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Overall ammonia, total nitrogen, chlorophyll a, enterococci and faecal coliforms and to a more limited

extent, total phosphorus, had patterns of decreasing concentrations with distance from the outfalls,

suggesting that the Burwood Beach WWTW outfalls is a significant source of these components in

the receiving environment. Conversely, in some sampling events, levels of total nitrogen, nitrites +

nitrates and occasionally chlorophyll a were elevated at similar levels across all sites, including

outfalls, mixing zone and reference sites.

A trigger index was created which provides a single value to represent the frequency and magnitude

of various parameters that exceeded the respective water quality guideline (i.e. ANZECC 2000; EPA

2000 or NMHRC 2008) across site and depth. The application of the trigger index shows the

frequency and magnitude that the chemistry results exceeded the water quality guidelines. In

particular, ammonia, total phosphorus, enterococci and faecal coliforms exceeded the guidelines

around the outfalls and then mixing zone with a higher magnitude and frequency in comparison to the

reference sites. This information is summarised in Table 4.2.

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Table 4.2 Samples that exceeded the associated water quality guideline values.

July 2011

Parameter WQ Guideline

Outfall Mixing Zone Reference

N %

Exceeded N

%

Exceeded N

%

Exceeded

Ammonia as N (mg/L) 0.021 22 50 32 47 4 0

Nitrate + Nitrite (mg/L) 0.0251 22 100 32 100 4 100

Total Nitrogen as N (mg/L) 0.121, 2 22 55 32 44 4 0

Total Phosphorus as P (mg/L) 0.0251,2 22 9 32 3 4 0

Chlorophyll a (mg/m3) 11 22 5 32 0 4 0

Enterococci (CFU/100ml) 95th percentile ≤ 403 22 55 32 47 4 0

Faecal Coliforms (CFU/100ml) 50% of values ≤1503 22 55 32 41 4 0

October 2011



N %

Exceeded N

%

Exceeded N

%

Exceeded

Ammonia as N (mg/L) 0.021 16 13 40 5 8 0







February 2012



N %

Exceeded N

%

Exceeded N

%

Exceeded

Ammonia as N (mg/L) 0.021 16 31 48 10 8 0







1 ANZECC (2000),

2 NSW EPA (2000),

3 NHMRC (2008)

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Table 4.2 (continued) Samples that exceeded the associated water quality guideline values.

April 2012



N %

Exceeded N

%

Exceeded N

%

Exceeded

Ammonia as N (mg/L) 0.021 16 6 48 8 8 25







June 2012



N %

Exceeded N

%

Exceeded N

%

Exceeded

Ammonia as N (mg/L) 0.021 16 69 48 29 8 13







October 2012



N %

Exceeded N

%

Exceeded N

%

Exceeded

Ammonia as N (mg/L) 0.021 16 94 48 40 8 0







1 ANZECC (2000),

2 NSW EPA (2000),

3 NHMRC (2008)

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Table 4.2 (continued) Samples that exceeded the associated water quality guideline values.

February 2013



N %

Exceeded N

%

Exceeded N

%

Exceeded

Ammonia as N (mg/L) 0.021 16 50 48 15 8 0







April 2013



N %

Exceeded N

%

Exceeded N

%

Exceeded

Ammonia as N (mg/L) 0.021 16 75 48 35 8 13





Enterococci (CFU/100ml) 95th percentile ≤ 403 16 81 48 33

8 0


1 ANZECC (2000),

2 NSW EPA (2000),

3 NHMRC (2008)

Multivariate analysis suggests that the main factor that influenced the multivariate water quality profile

(which consisted of the results of the nutrients, chlorophyll a and faecal indicators) was sampling time.

Multidimensional scaling (MDS) plots show that samples taken within the same day or within the

same sampling event are the most similar. This shows that temporal variability is an important

component and contributes to a large amount of the variability in the water quality dataset, which is

not surprising or uncommon in marine water quality programs.

The median and 95th percentile water quality results for key parameters are outlined in Table 4.2.

Overall, the results of the Burwood Beach Water Quality Study suggest that the Burwood Beach

outfalls is having an effect on local water quality at distances of at least 500 m from the diffusers.

There is a clear pattern of decreasing concentrations, with higher results in the outfalls and mixing

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zones in comparison to the reference zone, for the parameters of ammonia, organic nitrogen,

inorganic nitrogen, total nitrogen, total phosphorus, enterococci and faecal coliforms.

Table 4.3 Summary of median and 95th percentile data by zone

Parameter

Median Level 95th percentile Guideline

Value

outfalls mixing zone reference outfalls

mixing zone reference

Turbidity (NTU) 2.60 2.40 1.45 12.80 7.16 9.79 61

Temperature (oC) 18.44 18.95 20.63 22.90 22.90 23.10 15- 352

Conductivity 5.50 5.50 5.50 5.67 5.67 5.68 -

Salinity 38.60 38.60 38.50 41.10 41.10 41.10 -

Dissolved oxygen 7.49 7.40 7.25 9.62 9.69 9.82 -

pH 8.32 8.28 8.27 8.45 8.45 8.39 8- 8.41

Ammonia as N (mg/L) 0.017 0.003 0.003 0.093 0.060 0.021 0.021

Organic Nitrogen as N (mg/L) 0.115 0.080 0.080 0.230 0.200 0.282

-

Nitrite + Nitrate as N (mg/L) 0.005 0.003 0.003 0.087 0.079 0.073 0.0251

Inorganic Nitrogen as N (mg/L) 0.031 0.012 0.006 0.127 0.079 0.060

-

Total Nitrogen as N (mg/L) 0.160 0.100 0.100 0.340 0.220 0.353 0.111,2

Total Phosphorus as P (mg/L) 0.013 0.009 0.008 0.033 0.020 0.017

0.0251,2

Chlorophyll a (mg/m3) 0.50 0.50 0.25 2.00 1.75 0.80 1

Faecal Coliforms (CFU/100ml) 125.00 6.00 0.50 757.00 202.50 54.60

50% of values <

1501

Enterococci (CFU/100ml) 26.50 4.00 1.00 180.00 108.00 16.90

95th percentile

< 40 3

1 ANZECC (2000),

2 NSW EPA (2000),

3 NHMRC (2008)

In summary, the water quality data indicates a footprint of the outfalls discharge extending to about

500 m from the outfalls.

4.2.2 Marine Sediment

The Burwood Beach Sediment Study was undertaken to determine whether there are differences in

the concentrations of organic solids, measured as total organic carbon (TOC) along the effluent and

biosolids dispersion pathway, as a function of distance from outfalls, and if so, whether these

differences also apply to metals in the sediment. The study aimed to establish and document the

potential area in which organic solids and metals are elevated, providing insights into the spatial

extent of any potential impact associated with the discharge. Sediment sampling was undertaken on

two occasions (December 2011 and October 2012). Samples were collected using a gradient

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sampling design with seven locations positioned at distances of approximately 10 m, 20 m, 50 m,

100 m, 200 m, 500 m and 2,000 m (reference areas) from the biosolids outfalls. Two additional

reference sites (located > 2,000 m) were added during the second sampling period (Merewether and

Redhead). Sediments were tested for particle size distribution, TOC and a suite of 18 metals.

Particle size analysis found that sediment samples collected at Burwood Beach consisted mainly of

sand (0.06 - 2.00 mm) with some gravel (> 2 mm) and silt (2 - 60 µm). One sample near the outfalls

(at site 10SW) contained 22% clay in the December 2011 sampling round, with the rest of the

samples containing less than 2% clay. In October 2012 most samples were again mostly composed

of sand, no sample contained more than 7% clay and two samples contained large amounts of gravel

(Merewether - 27% and 10SE - 19%). Most samples contained a majority of particles between 300

and 1180 µm in both sampling rounds. There was an increased proportion of larger particles at the

outfalls sites 10SW and 10SE in December 2011 and at 10SE and Merewether in October 2012. The

reference site Redhead had a similar particle size distribution to most other samples. Multi-

dimensional scaling revealed that most sites sampled share a similar particle size distribution, with

the exception of the Merewether reference site and four outfalls samples (two from 2011 and two from

2013). The similarity of particle size distributions across zones suggests that the biosolids and

effluent discharged from the Burwood Beach outfalls are not altering the physical characteristics of

sediments around the outfalls. This finding is in contrast to that of Bioanalysis (2007) who reported a

higher proportion of fine sediments close to the outfalls.

Most sediment samples collected contained similar and low levels of TOC (< 0.5%) and the levels of

TOC were consistent over the two sampling periods. There were three (of four) samples taken within

10 m of the outfalls which showed higher values (0.53%, 0.76% and 2.16%) compared to the rest (<

0.5%). Overall, TOC levels were low at all sites, with the highest levels recorded at sites nearest to

the outfalls (i.e. within 10 m). Sites in the midfield (mixing zone) and reference zones had very similar

levels of TOC, which were lower than those around the outfalls. Multivariate analysis of metal and

TOC sediment concentration data found that there were significant differences in levels between

outfalls (< 50 m), mixing / midfield (50 - 500 m) and reference (> 2,000 m) zones. These results

suggest that a very small footprint (< 50 m) of organic enrichment exists around the outfalls.

None of the 18 metals analysed were found to exceed the ANZECC (2000) ISQG low impact

guideline levels except for one sample taken 20 m from the outfalls (at 20NE in October 2012) which

had a high concentration of antimony. The metals beryllium, cadmium, selenium and silver all

returned values which were less than the laboratory limit of reporting. Many of the metals tested

showed a trend for higher metal concentrations at sites around the outfalls relative to the midfield or

reference sites. These included barium, copper, lead, mercury and zinc. Results for manganese

suggest that there were higher concentrations of that metal in sediments at reference sites. The

remaining metals did not show any apparent trend with distance from the outfalls.

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Multi-dimensional scaling of TOC and metals data quite strongly grouped samples by zone, with all

midfield and reference sites closely clumped together. Outfalls sites were clearly segregated from the

midfield and reference sites. This indicates that a localised impact on sediment quality in the outfalls

impact zone (i.e. within 50 m) may be present. Sites located at distances greater than 50 m from the

outfalls were all very similar to each other. Multi-dimensional scaling did not indicate much difference

in the concentrations of metals and TOC in sediments between the two sampling periods.

After accounting for variation due to particle size and time and space, distance from the outfalls was

not found to be a significant predictor of metal and TOC concentration in sediment samples at

Burwood Beach. However, the factor zone was found to be significant. The results suggest that a

site’s distance from the outfalls does not determine the metal or TOC concentration in sediments in a

continuous or gradient fashion. However, what is strongly implied from the data is that within about

50 m from the outfalls there are significantly higher concentrations of metals and TOC relative to

elsewhere. It is likely that the combination of wastewater treatment, dispersion and dilution is

effective in preventing organic carbon accumulation in the Burwood Beach receiving environment at

distances greater than about 50 m.

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ZincVanadiumNickelMercuryManganeseLeadIronCopperChromiumCobaltBariumArsenicAntimonyAluminium

7

6

5

4

3

2

1

0

-1

-2

Sta

nd

ard

ise

d c

on

ce

ntr

ati

on

Outfall 0-50m

Midfield 50-500m

Reference >2000m

Zone

Figure 4.1. Boxplots showing standardised metal concentrations for each zone.

Standardisation was achieved for each variable by subtracting the mean and dividing by the standard deviation. In this graph the median is

represented by the horizontal line within each coloured box; the top and bottom of the coloured box represent the third (Q3) and first (Q1) quartile

respectively; the whiskers above and below extend to the highest and lowest values within the upper and lower limits determined by Q3+1.5(Q3-

Q1) and Q1-1.5(Q3-Q1) respectively; asterisks represent outliers in the data.

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301020-03413: Final Draft December 2013

4.2.3 Ecotoxicology

The objective of the Ecotoxicology Assessment at Burwood Beach WWTW was to assess the toxicity

of the effluent and biosolids discharge, using direct toxicity assessment (DTA) for two marine species

which are endemic to the site, or representative of species found in the New South Wales (NSW)

region and three standard toxicity tests. A number of previous ecotoxicological investigations have

been undertaken for the Burwood Beach WWTW and a summary of the results are provided in the

report and compared to the results obtained in this study.

Six bioassay or toxicity tests were undertaken over a two year period. The first year involved

quarterly sampling and testing while the second year included sampling every six months (for a total

of 6 sampling events). Samples were collected and tested in August 2011, December 2011, February

2012, May 2012, November 2012 and May 2013. Three toxicity tests were conducted on the

Burwood Beach effluent and biosolids for each sampling event;

72-hr microalgal growth inhibition bioassay using Nitzschia closterium,

1-hr fertilisation bioassay using the sea urchin Heliocidaris tuberculata and

72-hr larval development bioassay using the sea urchin, H. tuberculata.

The effluent and biosolids samples were collected as single or three-grab composite samples in the

discharge channels at the same time as samples were collected for routine monthly chemical testing.

The toxicity tests were carried out in accordance with standard protocols in a NATA-accredited

laboratory in Sydney (Ecotox Services Australasia; ESA).

The results of the 72-hr marine microalgal growth inhibition bioassays showed there is stimulation of

algal growth (i.e. hormesis) over the range of dilutions tested (6.3% to 100% effluent and biosolids in

seawater). This may be a response by the algae to nutrients in the effluent and the biosolids ( the

biosolids have a high effluent content and similar nurtrient concentrations as the effluent, but much

greater suspended solids concentrations).

The IC50 toxicity values (concentration that caused a response to 50% of the test population) for

marine algae ranged from 39.3- 100 % for effluent and 32.9- 74.2% for biosolids. These results are

similar to the ranges observed in 2001 (23%) and 2005 (24 - 34%) (ESA 2001; 2005).

The concentration of ammonia was measured in the biosolids samples and ranged from 3.4 to 26.7

mg/L. It is likely that the ammonia is stimulating growth at low concentrations and causing toxicity at

high concentrations under the test conditions.

The results of the 1-hr sea urchin fertilisation bioassay showed differing toxicities for the Burwood

effluent and biosolids samples and are reported as EC10 or EC50. The Burwood effluent samples

demonstrated little or no toxicity in all tests. However, Burwood biosolids samples demonstrated

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higher toxicity than the effluent samples for four of the six tests, with an average IC50 of 79%.

These results are consistent with what has been found previously for Burwood Beach biosolids

samples.

The results of the 72-hr sea urchin larval development bioassay for the Burwood effluent and

biosolids samples showed higher toxicity than for the other two types of tests. The IC50 of the

Burwood effluent samples ranged from 17 to 100% (average of 36 %) while the IC50 for biosolids

samples ranged from 17 to 43% (average of 26%). For May 2013, both the effluent and biosolids

samples showed the highest toxicity recorded when compared to the other five sampling events. A

Toxicity Identification Evaluation (TIE) was conducted in order to assess the potential chemicals

causing this toxicity.

TIE manipulations conducted during this study (i.e. in May 2013) and undertaken previously (SKM

2000) have identified ammonia as the cause of toxicity. The historical results highlight that since

2000, the toxicity associated with Burwood Beach effluent and biosolids samples is due to the

concentration of ammonia.

The November 2012 results for the 1-hr sea urchin fertisilation bioassay and the ammonia spiking

experiment suggested that ammonia was not the whole cause of the observed toxicity in the biosolids

sample and that some other constituent may also be contributing a toxic effect. This could not be

identified.

Results have indicated that the 72-hr sea urchin larval development bioassay continues to be the

most sensitive of the three bioassays. The EC50 values for the effluent samples ranged from 17%

observed in May 2013 to > 100% in February 2012. The EC50 values for the biosolids demonstrated

toxicity ranging from 17% observed in May 2013 to > 43% observed in February 2012.

Results from the November 2012 ammonia spiking experiment and May 2013 TIE investigations have

highlighted that the main cause of toxicity in both 72-hr marine algal growth inhibition test and the 72-

hr sea urchin larval development test is the concentration of ammonia. The results of this work

compliment previous DTA assessments which have highlighted that the 72-hr sea urchin larval

development bioassay is the most sensitive bioassay for the Burwood Beach effluent and biosolids

samples and shows ammonia is the cause of the toxicity observed (ESA 2005).

Ammonia has been measured in effluent and biosolids at median concentrations of 23mg/L and 24

mg/L, respectively (Hunter Water 2013) and dilution of the effluent and biosolids outfalls has been

modelled to be 100:1 and 200:1 dilution, respectively (CEE 2010). This dilution is sufficient to reduce

ammonia concentrations in the receiving environment to background levels and below the ANZECC

(2000) toxicant trigger value for ammonia of 0.91 mg/L, which is recommended to protect 95 % of

species in marine waters. Based on ANZECC (2000) recommendations, future DTA testing of

ambient waters in the Burwood Beach receiving environment could be appropriate to assess any

potential risk.

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4.2.4 Oyster Biomonitoring

The Boulder Bay Oyster Biomonitoring Study was undertaken to assess the potential for effluent

discharges to lead to bioaccumulation of chemicals over a range of spatial scales, using oysters as a

biomonitor. A specific requirement of the study was to establish the spatial extent of the area in which

there is a detectable increase in the concentration of chemicals in oysters that is related to the

outfalls.

Oysters were deployed for four eight weeks periods; 31 January to 2 April 2012, 22 May to 9 July

2012, 16 October to 18 December 2012 and 26 March to 22 May 2013. Nearly all oysters deployed

during the third monitoring period were lost due to tampering and analysis was not possible for this

period. Sydney rock oysters, Saccostrea glomerata, were deployed at seven sites at range of

distances from the outfalls in an approximate NE / SW direction; 0 m (outfalls A and B), 100 m NE

and SW, 500 m NE (A and B) and SW and 2,000 m NE and SW. The seven sampling sites were

distributed along the known dispersion pathway (WRL 2007) of the plume in order to establish a

gradient of exposure.

Concentrations of a suite of organic compounds, metals and metalloid chemicals were measured in

oyster tissue before and after each deployment. Analysis of organic chemicals included a suite of

organochlorine (OC) and organophosphate (OP) pesticides, polychlorinated biphenyls (PCBs)

congeners and total PCBs (summation of PCB congeners). Analysis for metals included arsenic,

cadmium, cobalt, copper, iron, lead, manganese, selenium, nickel, silver and zinc.

Organic chemical levels in oyster tissue at all sites, including the outfall site, were consistently lower

than available ANZFA Food Standard MRLs for molluscs (ANZFA 2011). For the May - July 2012

and the March - May 2013 deployments, all OCs, OPs, PCB congeners and total PCBs were lower

than the LOR (0.01 mg/kg). As the majority of organics were below the LOR, statistical comparisons

were not carried out. However in the January - April 2012 deployment, some OC pesticides (i.e.

heptachlor, trans-chlordane, cis-chlordane and dieldrin) were detected, which does indicate their

presence in the environment. The Burwood Beach WWTW discharge is likely to be a source of these

chemicals and should be continued to be monitored.

There is no evidence that Burwood Beach WWTW discharge causes bioaccumulation of metals or

metalloids. Most metals were at low concentrations in oysters following deployment. No

metals/metalloids were found to exceed the available ANZFA MRLs (ANZFA 2011).

Oysters were tested for metals/metalloids prior to each deployment and most metals/metalloids were

found to increase following deployments in Burwood Beach WWTW receiving waters, including

arsenic, cadmium, copper, lead, mercury, nickel, selenium, silver and zinc. Increases in

metal/metalloid concentrations relative to time zero samples do not appear to be related to the outfall

as there were no patterns between elevated concentrations and sites or distance from the outfall.

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4.2.5 Seafood Bioaccumulation

The Burwood Beach Seafood Bioaccumulation Study was undertaken to provide information

concerning the potential for bioaccumulation of chemicals or microbial contamination in locally

consumed marine fish species collected from around the Burwood Beach outfalls. Targeted species

Yellowtail scad (Trachurus novaezelandiae) and Australasian snapper (Pagrus auratus) were

collected (by hand lining) from the receiving environment of the Burwood Beach wastewater treatment

works (WWTW) and two reference locations (Redhead and Merewether) during February 2013,

March 2013 and April 2013.

Microbiological analysis of thermotolerant coliforms and Escherichia coli was undertaken on fillet

tissue samples of both species. During every sampling event there were individuals of yellowtail scad

and snapper from the Burwood Beach sampling site that had levels of thermotolerant coliforms and

E. coli which were above the limit of reporting (LOR; 1 - 10 CFU/g). Concentrations in all yellowtail

scad and snapper sampled from the Redhead and Merewether sites during the three sampling events

were below the LOR. On average, concentrations of E. coli in a small proportion of yellowtail scad

and snapper from Burwood Beach during every sampling event exceeded the NSW Food Authority

guideline (ANZFA 2001) of < 3 CFU/g for satisfactory levels of E. coli in ready to eat food, which

would be applicable where the fish was consumed raw. Supplementary microbial sampling and analysis was also undertaken in September 2013 to focus on

greater replication at Burwood Beach and fish cleaning processes. Fifteen individuals were collected.

In fillets with skin and scales attached, thermotolerant coliforms were detected in two fillet samples (at

270 CFU/ g and 5 CFU/ g) and in two fillet samples that had been scaled and washed (at 84 CFU/ g

and 6 CFU/ g). E. coli were detected in two fillet samples with skin and scales attached (at 75 CFU/ g

and 4 CFU/ g) and two fillet samples scaled and washed (at 27 CFU/ g and 6 CFU/ g).

Advice from NSW Food Authority (NSW FA) to Hunter Water regarding the microbiolgical results

indicated that the associated burden of disease appeared to be low which implied the level of risk was

low. This was seen as being consistent with factors identified regarding typically small catch. Fish are

rarely consumed raw and there were low and sporadic E. coli levels, with pathogen levels being lower

again.

Concentrations of polychlorinated biphenyls (PCBs) and PCB aroclors were below the LOR in all

yellowtail scad and snapper samples collected during all sampling events at all three sites.

Concentrations of metals and metalloids, including total arsenic, inorganic arsenic, cadmium, copper,

lead, mercury and zinc in yellowtail scad and snapper tissue were generally low for all sampling

events. No metal or metalloid was found to exceed the available Maximum Residue Limits (MRLs) for

fish (ANZFA 2011). There were no metals or metalloids that were consistently elevated at Burwood

Beach in comparison to the two reference locations, Redhead and Merewether.

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In summary, the Burwood Beach Seafood Bioaccumulation Study found that there were elevated

levels of microbial indicators (thermotolerant coliforms and E. coli) in fish tissue from samples

collected at the Burwood Beach site in comparison to fish sampled from the two reference locations.

There were however no results to suggest that the targeted species had bioaccumulated

concentrations of any of the other tested chemicals (i.e. PCBs, PCB arochlors, metals and metalloids)

to elevated levels during the targeted sampling events.

4.2.6 Human Health Risk Assessment

Human Health risk assessment was undertaken separately to the MEAP (apart from microbial

assessments in the Seafood Study).

A Community Reference Group (CRG) was established as part of the Environmental Impact

Assessment (EIA) process for the Stage 2 upgrade. This CRG has been renewed and will continue to

operate throughout the planning phase of the Stage 3 upgrade. The CRG meets regularly and

provides input to Hunter Water on various aspects of the plant, from a community perspective.

Members of the community hold a range of views on ocean discharge, depending on where they live,

their use of ocean waters, whether or not they are involved in fishing or surfing or regular swimming,

and their environmental philosophy.

Beachwatch data is collected regularly from nearby beaches. Beachwatch was established in 1989 in

response to community concerns about the impact of sewage pollution on human health and the

water quality at Sydney's ocean beaches. Beachwatch provides regular information on water quality

to enable people to make informed decisions about where and when to swim. A total of 127

swimming locations are monitored in the Sydney, Hunter and Illawarra regions, with a further 129

sites monitored in partnership with local councils along the NSW coast (NSW Government 2013).

Daily bulletins, monthly and annual reports for all NSW beaches monitored in the program can be

obtained from http://www.environment.nsw.gov.au/beachapp/default.aspx (NSW Government 2013).

Beaches nearby to Burwood Beach that are monitored by Beachwatch for faecal indicators (i.e.

enterococci) include Bar, Merewether, Burwood North and Burwood South. During 2011- 2012 and

2012- 2013, these beaches were graded as suitable for swimming most of the time but it was noted

that the waters may be susceptible to sources of faecal contamination from land runoff. These results

show that enterococci levels increase slightly with increasing rainfall. It was outlined that enterococci

levels often exceed the safe swimming limit after rainfall at Bar Beach (after 10 mm) and Merewether

Beach (after 20 mm). For Burwood North and Burwood South, it was outlined that enterococci levels

occasionally exceed the safe swimming limit after 10 mm or more of rainfall.

A combined Quantitative Microbial Risk Assessment (QMRA) and hydrodynamic modeling study was

undertaken in 2010 to explore the fate, transport and risk posed to bathers that use Newcastle

Beaches by pathogens in Burwood Beach effluent and biosolids (Roser et al. 2010). Pathogens

assessed included:

http://www.environment.nsw.gov.au/beachapp/default.aspx

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• All gastrointestinal pathogens collectively (enterococci are used as a surrogate).

• Adenovirus

• Giardia lamblia

• Cryptosporidium spp.,

• Campylobacter spp.,

• Rotavirus (risk not assessed ultimately as few were detected).

QMRA modelling provided a detailed picture of potential risks under a range of exposure scenarios.

Baseline risk estimates were consistent with Newcastle’s beaches typically having very good quality

bathing water and in line with NHMRC Guideline benchmarks. However, under hazardous event

conditions effluent discharges could impact on the beaches and pose an elevated health risk.

Biosolids impacts were much smaller, largely due to the small volume discharged. Estimated risks

varied substantially between seasons, pathogens, discharge types, solar inactivation rates and bather

populations but not locations or discharge rates.

Under baseline conditions (summer, shoreline bathers) elevated gastrointestinal illness risk above

“grade A” classification was estimated to occur with an Exceedence Probability of 0.05 to 0.08 on

sunny days. But in the absence of sunlight, surfer ingesting 200 mL of seawater typically showed

elevated gastrointestinal illness risk above Grade A waters with an exceedence probability in the

range of 0.2 to 0.5. Surfer risk was judged as higher, mainly because of the assumed seawater

exposure (7 fold normal bathers) and their use of the ocean in winter and early morning when

inactivation of pathogens by sunlight was reduced.

Decreased water quality events were episodic, occurred at any time of day and were associated with

concurrent water column destratification, on-shore currents, and strong or extended duration on-shore

winds. The risks between beaches did not vary greatly overall, specific events could impact each

beach very differently.

The study showed that solar inactivation could effectively moderate risk during daylight, however, its

benefit was compromised by potential short travel times (<1 day) of the effluent plume to shore or

surfing areas.

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4.2.7 Reef Ecology

The aim of the Burwood Beach Reef Ecology Study was to assess the characteristics of benthic reef

assemblages (flora and fauna) along the effluent and biosolids dispersion pathway from the existing

outfalls to establish the impact footprint, establish the gradient of impact with distance to the edge of

the measurable footprint and predict the footprint of future impacts. Surveys were undertaken at four

increasing distances from the Burwood Beach outfalls (including 10 m, 50 m, 100 m and > 2,000

m). Four replicate sites were surveyed at each distance, with two replicate sites located in an

approximate NE and SW direction from the outfalls (the direction of the main current flow). Four reef

ecology surveys were undertaken over the study period (December 2011 / January 2012, April 2012,

October 2012 and April 2013). At each site, digital photographs of ten randomly placed 0.25 m2

photoquadrats were collected by SCUBA divers. Digital photographs were analysed in the program

Coral Point Count (CPCe) where reef flora and fauna species were identified and their cover was

determined. Mean species abundance, richness and diversity were then calculated.

During the December 2011 reef survey at Burwood Beach poor visibility and sand inundation over

many of the low profile reefs limited data collection to the 100 m and reference sites south of the

outfalls. All sites were surveyed during the April 2012, October 2012 and April 2013 surveys.

The abundance, richness and diversity of benthic flora and fauna were generally low during all

surveys at Burwood Beach. This is most likely to be attributed to the reefs being periodically

inundated by sand.

The most dominant algae recorded at Burwood Beach were red algae. The occurrence of brown

macroalgae was limited to kelp, Ecklonia radiata, at the reference sites. The only green macroalgae

observed, Caulerpa filiformis, is thought to be an invasive species which has recently been observed

to rapidly dominate algal assemblages in shallow subtidal regions along the NSW coast.

The marine fauna recorded at the Burwood Beach outfalls and surrounding reefs was mainly

comprised of porifera (sponges), followed by cnidarians (hydroids, sea anemones, corals and sea

pens), echinoderms (sea stars, urchins and feather stars) and ascidians (sea squirts).

It is likely that intermittent sand inundation over the low profile subtidal reefs at Burwood Beach has a

large influence on the structure of the benthic communities present (i.e. low abundance and

diversity). This may contribute to the high spatial and temporal variability observed in both current

and previous studies and also obscure any impact of the Burwood Beach outfalls on reef

communities.

Overall, there was no consistent gradient in effect with distance from the outfalls that would indicate

the observed differences in assemblages were attributable to the operation of the Burwood Beach

outfalls. This is consistent with the results of previous studies.

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4.2.8 Fish Distribution Study

The Burwood Beach Fish Distribution Study has provided useful baseline information regarding the

abundance and diversity of fish on reef habitat around the existing outfalls. Due to the lack of

equivalent reef habitat in the surrounding area and the presence of mobile sand, inference of impact

from the outfalls based on a gradient of effect cannot be determined with confidence. The use of fish

distribution as a biological indicator is limited by the lack of suitable equivalent habitat for monitoring.

Overall, significant spatial and temporal differences were found between reef fish assemblages

located at the Burwood Beach outfalls, mixing zone and reference sites. The Underwater Visual

Census (UVC) data indicated an impact of the outfalls on species abundance, with higher abundance

at the outfalls than mixing zone and reference sites. Overall trends in mean species richness

measured using UVC were similar to those seen for mean abundance, with typically higher species

richness values recorded at the outfalls impact sites followed by the mixing zone then the reference

sites. Results for species diversity were variable and did not show any consistent trends over the four

sampling events.

Both of the warm water surveys had higher species diversity levels than the cool water survey

periods.

The results of the Baited Underwater Video Survey (BRUVS) survey showed no significant increase

in fish abundance at the outfalls compared to the other sites. Species richness measured using

BRUVS data was lowest at the outfalls sites and appeared to increase with increasing distance from

the outfalls (but no significant differences were found). Species diversity was highest at the mixing

zone sites and lowest at the outfalls’ and northern reference site.

In summary, the UVC data show higher fish abundance and richness at the outfalls sites and lower

abundance and richness at the reference sites. Thus the UVC data collected for the Burwood Beach

Fish Distribution Study provides no evidence that the outfalls impact on reef fish communities in terms

of decreasing fish abundance.

The BRUVS surveys show no significant differences between the outfalls site and the other sites.

Differences between the UVC and BRUVS datasets, especially in regards to the abundances of

individual species recorded were apparent.

4.2.9 Marine Infauna

The Burwood Beach Marine Infauna Study was undertaken to assess the distribution of marine

infauna along the effluent dispersion pathway, as a function of distance from the outfalls. The key

objective of the Burwood Beach Marine Infauna Study was to monitor changes in the distribution of

marine infauna along the effluent dispersion pathway, as a function of distance from the outfalls.

Infauna sampling was undertaken using a gradient sampling design with sites positioned at increasing

distances from the outfalls (10 m, 20 m, 50 m, 100 m, 200 m and 2,000 m) along two radial axis

(approximately north-east and south-west). Surveys were undertaken during December 2011, April

2012, October 2012 and April 2013.

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Overall, there were no detectable impacts on infauna abundance, richness and diversity. The only

apparent trend that could be related to discharge was the high polychaete ratio observed at sites

closest to the outfalls, where a potential zone of effect is within 20 m of the outfalls. This result

corresponds with a high level of total organic carbon (TOC) that was detected within 10 m of the

outfalls during the Burwood Beach sediment study. These findings may indicate an impact of higher

organic loading very close to the outfalls (in comparison to all other sites) with a zone of impact < 20

m.

A high level of variability was found in infauna assemblages and this contributed to the difficulty in

detecting significant differences between sites that could be attributed to the discharge from the

outfalls. Significant differences may not have been detected due to insufficient power to detect

differences.

Burwood Beach WWTW is located in a high energy coastal environment where large movements of

sand occur intermittently offshore. High variability is also common in studies of infauna assemblages.

Although significant differences were found between sites, these differences were confined within

sampling events and the patterns were not consistent at the distance level or between sampling

events.

Similar to the findings of others, there was significant temporal and spatial variability in the abundance

and composition of infauna communities in the receiving environment surrounding the Burwood

Beach WWTW outfalls. As there were no consistent trends with distance from the outfalls this high

level of variability makes it difficult to determine the potential effects of increased flows on marine

infauna communities in the receiving environment with any certainty.

4.3 Summary

Table 4.4 provides a summary of observations from the different monitoring studies.

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Table 4.4. Summary of significant observations from the monitoring studies.

Study Impact/s Detected? Y/N

Impacted Measure Distance from outfall or effluent/biosolids dilution that a pattern of elevated values was observed

Proportion of sampling events observed

Guideline exceeded?1

Water Quality Y ammonia 0 m, 30 m, 100 m, 250 m and 500 m 75% > 0.02 mg/L (ANZECC 2000)

organic nitrogen 0 m, 30 m, 100 m, 250 m and 500 m 50%- < 75% n/a

dissolved inorganic nitrogen 0 m, 30 m, 100 m, 250 m and 500 m 50%- < 75% n/a

total nitrogen 0 m, 30 m, 100 m, 250 m and 500 m 75% > 0.12 mg/L (ANZECC 2000; EPA 2000)

total phosphorus 0 m, 30 m, 100 m and 250 m 75% > 0.025 mg/L (ANZECC 2000; EPA 2000)

chlorophyll a 0 m, 30 m, 100 m, 250 m and 500 m 25%- < 50% > 1 mg/L (ANZECC 2000)

enterococci 0 m, 30 m, 100 m, 250 m and 500 m 50%- < 75% 95thile of values ≤40 CFU/100 mL (NHMRC 2008)

faecal coliforms 0 m, 30 m, 100 m, 250 m and 500 m 50%- < 75% 50% of values ≤ 150 CFU/ 100 mL (ANZECC 2000)

Sediment Y total organic carbon 10 m 75% n/a

antimony 20 m 50%- < 75% > 2 mg/kg (ISQG low, ANZECC 2000)

aluminum 10 m, 20 m and 50 m 75% n/a

barium 10 m, 20 m and 50 m 75% n/a

chromium 10 m 50%- < 75% < 80 mg/kg (ISQG low, ANZECC 2000)

cobalt 10 m, 20 m and 50 m 75% n/a

copper 10 m and 20 m 50%- < 75% < 65 mg/kg (ISQG low, ANZECC 2000)

lead 10 m, 20 m and 50 m 75% < 50 mg/kg (ISQG low, ANZECC 2000)

mercury 10 m and 20 m 75% < 0.15 mg/kg (ISQG low, ANZECC 2000)

nickel 10 m 50%- < 75% < 21 mg/kg (ISQG low, ANZECC 2000)

zinc 10 m, 20 m and 50 m 75% < 200 mg/kg (ISQG low, ANZECC 2000)

Seafood Bioaccumulation

Y thermotolerant faecal coliforms outfall 75% n/a

Escherichia coli outfall 75% > 3 CFU/g (NSW FA 2001)

Oysters Y heptachlor outfall 25%- < 50% < 0.05 mg/kg (ANZFA 2011)

trans- chlordane outfall and 2000 m 25%- < 50% < 0.05 mg/kg (ANZFA 2011)

cis-chlordane outfall 25%- < 50% < 0.05 mg/kg (ANZFA 2011)

dieldrin outfall 25%- < 50% < 0.1 mg/kg (ANZFA 2011)

Ecotoxicology Y Microalga (N. closterium) 72-hr growth inhibition

lowest LOEC of 50 % dilution for effluent and 25 % for biosolids- main cause is likely ammonia. Hormesis (algae stimulation) observed at low concentrations.

50%- < 75%

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Sea Urchin (H. tuberculata) 1-hr fertilisation lowest LOEC of 50 % dilution for effluent and 12.5% for biosolids.

25%- < 50%

Sea Urchin (H. tuberculata) 72-hr larval development.

lowest LOEC of 12.5 % dilution for effluent and biosolids- main cause is likely ammonia.

75%

Reef Y Change in reef species assemblages and siltation around outfall (reduced macroscopic taxa).

10 m and 50 m 50%- < 75% poor visibility and sand cover influenced the data collection and interpretation

Fish Y Higher fish abundance, richness and diversity by UVC

outfall and mixing zones 75%

Infauna Y Increased ratio of polychaetes to other taxa 10 m and 20 m 50%- < 75% high variability in infaunal assemblages influenced the ability to detect differences

1 n/a= no defined guideline for that parameter

ANZFA (2011). Australian food standards code. Australia New Zealand Food Authority, ACT, Australia. ANZECC and ARMCANZ. (2000) 'Australian and New Zealand Guidelines for Fresh and Marine Water Quality.' (Australian and New Zealand Environment and Conservation Council and Agriculture and Resource Management Council of Australia and New Zealand). NHMRC (2008) ‘Guidelines for Managing Risks in Recreational Waters’. (http://www.nhmrc.gov.au/guidelines/publications/eh38) NSW Food Authority (2001). Microbiological quality guide for ready-to-eat foods. A guide to interpreting microbiological results. http://www.foodauthority.nsw.gov.au/_Documents/science/microbiological_quality_guide_for_RTE_food.pdf. Date accessed: 15th April 2013.

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5. INTEGRATED MONITORING ASSESSMENT

5.1 Assessment Framework

Following the concepts and monitoring framework set out in the ANZECC/ARMCANZ Guidelines

(2000), a series of integrated monitoring tasks have been used to identify potential changes in

selected indicators at a range of reporting scales (temporal and spatial) and habitat types. The MEAP

incorporates a mix of complementary physical, chemical and biological indicators to assess the

overall effect of waste waters on the ecological health of the marine ecosystem.

The use of a combination of biological, bio-chemical and physicochemical assessments enhances the

confidence in correctly attributing causes to any observed patterns: biological indicators directly

assess the effects of the outfalls on the ecosystem, while physicochemical indicators may provide

explanation for any biological patterns observed. This affords a more complete overall assessment or

‘weight of evidence’ in relation to ecosystem health.

The present monitoring program has shown that measurement of change may be difficult in some

biological indicators (i.e. reef and infauna) but ia apparent in other physicochemical indicators.

The current integrated monitoring program is shown in the framework below. The indicators were

developed based on the earlier studies undertaken in the receiving environment of Burwood Beach

WWTW (e.g. NSW EPA 1994, 1996; The Ecology Lab 1996, 1998; AWT 1996, 1998, 200, 2003;

SKM 1999, 2000; ESA 2001, 2005; BioAnalysis 2006; CEE 2007, 2010; Andrew-Priestley 2011;

Andrew-Priestley et al. 2012) and are based on their sensitivity to the effluent and biosolids,

prevalence in the receiving environment and ability to inform the interpretation of other monitoring

tasks.

The framework of assessment of the MEAP is provided in Figure 5.1.

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301020-03413 :Final Draft December 2013

Figure 5.1 MEAP Framework of assessment

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5.2 Key Processes and Conceptual Models

The main impacts associated with WWTWs are those that arise from changes in the receiving

environment due to increased levels of nutrients, dissolved oxygen, pathogens, toxicants and

suspended solids. Concept diagrams of the pathways of impacts are outlined below for:

Nutrients (Figure 5.2);

Dissolved oxygen, pathogens and toxicants (Figure 5.3); and

Particulate matter (Figure 5.4).

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1

2

Figure 5.2 Concept of Impact Pathways for changes in Nutrients 3

Images courtesy of Integration and Application Network, University of Maryland Center for Environmental Science http://ian.umces.edu/imagelibrary/).

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4 5

Figure 5.3 Concept of Impact Pathways for changes in Dissolved Oxygen, Pathogens and Toxicants 6


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7

8

Figure 5.4 Concept of Impact Pathways for changes in Particulate Matter 9


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5.3 Decision Criteria

The current NWQMS approach recommends an integrated approach for managing water quality

which comprises:

Chemical-specific triggers coupled with water quality monitoring;

Direct toxicity assessment; and

Biological monitoring.

Each of these has been applied in the MEAP as part of the decision making process of whether there

is an impact attributable to the outfalls.

5.3.1 Environmental Values and Water Quality Objectives

Marine Water Quality Objectives for NSW Ocean Waters (OEH 2005) were applied as part of the

development and assessment of the MEAP. These guidelines are based on the national framework

outlined in the ANZECC/ARMCANZ Guidelines (2000). The aim of these objectives is to ensure that

the environmental values and uses that the community places on NSW oceans are recognised and

protected by coastal management. The objectives are not regulatory or mandatory, but rather provide

a tool for strategic planning and development assessment.

The Marine Water Quality Objectives for NSW Ocean Waters (OEH 2005) provide Marine

Environmental Values and Water Quality Objectives specific to the Hunter and Central Coast region,

along with example indicators (Table 5.1). These objectives provide a framework for useful

indicators that can be measured to help meet marine environmental values in the Hunter catchment

area.

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Table 5.1. Marine Values and Water Quality Indicators for the Hunter catchment area.

Marine

Environmental Value

Water Quality Objective Indicators

Aquatic ecosystem

health

To maintain or improve the

ecological condition of ocean

waters.

Biological

Frequency of algal blooms

Bioaccumulation of contaminants

Physicochemical

Nutrients

Turbidity

Toxicants in coastal waters

Metals

Pesticides

Toxicants in bottom sediments

Metals

Organochlorines

Primary contact

recreation

To maintain or improve ocean

water quality so that it is suitable

for activities such as swimming

and other direct water contact

sports.

Microbiological

Faecal coliforms

Enterococci

Physicochemical

Visual clarity

Secondary contact

recreation

To maintain or improve ocean

water quality so it is suitable for

activities such as boating and

fishing where there is less bodily

contact with the waters.

Microbiological

Faecal coliforms

Enterococci

Visual amenity To maintain or improve ocean

water quality so that it looks clean

and is free of surface films and

debris.

Indicators

Surface films and debris

Nuisance organisms

Aquatic foods To maintain or improve ocean

water quality for the production of

aquatic foods for human

consumption (whether derived

from aquaculture or recreational,

commercial or indigenous fishing).

Microbiological

Faecal coliforms

Toxicants

Metals

Organochlorines

Physicochemical

Suspended solids

Temperature

Source: Marine Water Quality Objectives for NSW Ocean Waters – Hunter and Central Coast. Department of Environment and

Conservation NSW, 2005 (http://www.environment.nsw.gov.au/water/mwqo/index.htm)

http://www.environment.nsw.gov.au/water/mwqo/index.htm

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5.3.2 Trigger Values

Appropriate trigger values were identified as part of the consultation process of the MEAP. The

applied trigger values for each of the studies that involved quantitative measurements of chemicals or

microbial indicators are outlined below.

ECOTOXICOLOGY

The Ecotoxicology Study indicated that there was toxicity on the measured endpoints which resulted

in subsequent TIE investigations. TIE highlighted that ammonia was the main cause of toxicity in two

of the three DTA tests. The ANZECC (2000) toxicant trigger value for ammonia, which is

recommended to protect 95% of species in marine waters, was used to show that the modeled

dilution should be sufficient to reduce ammonia concentrations measured in effluent and biosolids

below this trigger. The trigger value level for a 95% protection of marine species is 0.910 mg/L for

total ammonia.

WATER QUALITY

As requested by the NSW EPA during initial consultation, the water quality objectives in this study

were required to address aquatic ecosystem health and primary contact recreation (i.e. swimming,

diving and surfing) for NSW marine waters.

Water quality results have been compared to the respective guideline levels for these objectives

taken from:

NSW EPA (2000) - NSW Marine Water Quality Objectives for the Hunter and Central Coast

(http://www.environment.nsw.gov.au/water/mwqo/index.htm);

ANZECC (2000) Guidelines for Fresh and Marine Water Quality (Table 3.3.2: Default

trigger values for slightly to moderately disturbed marine ecosystems in South-eastern

Australia) (http://www.environment.gov.au/water/publications/quality/nwqms-guidelines-4-

vol1.html); and

NHMRC (2008) - Guidelines for Managing Risks in Recreational Waters.

(http://www.nhmrc.gov.au/guidelines/publications/eh38).

Total nitrogen levels were often exceeded above the ANZECC (2000) guideline across all sites, even

reference. Development of a locally developed trigger level would be more appropriate for future

programs.


http://www.nhmrc.gov.au/guidelines/publications/eh38

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SEDIMENTS

Concentrations of metals in sediments were compared to the Low Interim Sediment Quality

Guidelines (ISQG) provided by ANZECC (2000).

OYSTER AND F ISH B IOACCUMULATION

The ANZFA (2011) outlines MRLs for metals/metalloids and organic chemicals (OPs, OCs and PCBs)

in oysters and fish.

For the Oyster Study, MRLs were used for comparison to assess whether chemicals were present at

concentrations of concern in the absence of other available guidelines. These guidelines have been

used as a point of comparison in other similar studies. But it should be noted that they are not

applicable in terms of health risks for human consumption of oysters as the main aim of this study

was to use oysters as a biomonitor for environmental contamination, not to assess whether chemicals

exceed concentrations in oysters intended as a food source.

SEAFOOD M ICROBIAL ASSESSMENTS

The NSW FA specifies guidelines for the microbiological examination of faecal indicators and

pathogens in ‘ready to eat’ food (2001). This was applied to the measurements of E. coli and

Salmonella in the seafood study, to determine whether levels pose a risk. One limitation of this

guideline is that it applies to ‘ready to eat’ food, so would only be applicable to seafood that is

consumed raw as samples were not cooked prior to testing.

5.3.3 Statistical Analysis

Statistical analysis formed an important part of the MEAP and was applied as part of the assessment

process to determine whether results were significant.

Univariate analyses were undertaken in most of the studies to determine if there were significant

differences in single endpoints among sites or sampling events.

Multivariate analyses were undertaken in the ecological studies, i.e. Fish, Infauna and Reef Studies,

to determine if there were significant differences in assemblages among sites, distances or sampling

events and which taxa were driving the patterns of difference.

For the Water Quality, Sediment, Oyster and Seafood Studies, multivariate analysis was used to test

for differences in the suite of chemicals among sites, distances or sampling events and to identify

which measures were responsible for the patterns observed.

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6. ECOLOGICAL IMPACT ASSESSMENT

Ecological impact assessment is the process of identifying, quantifying and evaluating the potential

impacts of defined actions on ecosystems or their components (Treweek, 1999). This then provides a

basis for management of potential impacts through implementation of mitigation measures and

strategies to reduce impacts on the environment.

The most systematic way to assess the environmental effects of both the effluent and biosolids

discharge associated with the Burwood Beach WWTW, is to review the available multiple lines of

evidence to assess the degree or extent of impact measured as part of the monitoring program. This

can then be used to predict the likelihood of future adverse effects or to evaluate effects associated

with changes to treatment as part of plant upgrades.

The impact assessment has also considered the significance of the monitoring results from the MEAP

in the context of historical findings that provide greater confidence in relation to providing predictions

around spatial and temporal trends. As more than one risk may be of concern at a site, and in many

cases multiple risks do not operate independently, an integrated assessment approach has also been

taken that includes all aspects of the discharge that may affect the beneficial uses and ecological

values being assessed.

6.1 Potential Impacts

The potential impacts from discharge of sewage effluents on the receiving environment largely

depend on the volume of the discharge, the dilution of discharge, the composition of the discharge

and the concentrations present in the effluent. These are summarised in Section 2 for Burwood

Beach WWTW effluent and biosolids and this information provides an important context for this

assessment.

Table 6.1 provides a summary of the potential impacts associated with discharge of effluent and

biosolids to the ocean and a list of the studies undertaken as part of the MEAP.

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Table 6.1 Summary of Impact Assessment associated with Discharge of Effluent and

Biosolids, Burwood Beach

Study Potential Impact

Water Quality Toxicants

Nutrients

Elevated levels of pathogens or microorganisms in waters used for human related beneficial uses

Sediment Quality Toxicants

High organic loading from discharge of biosolids

Bioaccumulation of Toxicants

Presence of pathogens

Ecotoxicology Toxicity of whole effluent and biosolids on selected marine species

Oyster Bioaccumulation Bioaccumulation of toxicants

Seafood Biomonitoring Bioaccumulation of toxicants

Levels of microbial indicators

Reef Study

Change in reef species and assemblages caused by physical and chemical processes associated with discharges

Fish Study Change in the abundance and diversity of fish communities caused by physical and chemical processes associated with discharges

Infauna Study Change in the abundance and diversity of infauna communities caused by physical and chemical processes associated with discharges

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6.2 Toxicity

The final treated effluent and biosolids from Burwood Beach WWTW contains a wide range of

constituents that have the potential to adversely affect marine organisms in the receiving

environment. Impacts can arise through direct contact or ingestion of effluent or biosolids by marine

biota.

To assess the potential effects to marine species, bioassays or direct toxicity tests (DTAs) involving a

range of sensitive species have been conducted since 1996, although only using the biosolids. In the

current monitoring program, test species were exposed to both effluent and biosolids. Results from

the testing have been previously discussed in Section 4.2.3. The graphs below are a summary of

results from historical testing of biosolids and also include results from the 2013 effluent assessment

(Figure 6.1- Figure 6.3).

Figure 6.1 Percentage NOEC based on sea urchin fertilization test from 1996-2013. Note that

effluent min and max dilutions in 2013 were both 100 % NOEC.

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Figure 6.2 Percentage NOEC based on sea urchin larval development test, 1996-2013. Note

that effluent min dilution in 2013 was 6.3%.

Figure 6.3 Percentage NOEC based on microalgal inhibition test, 1996-2013.

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The results of the 72-hr sea urchin larval development bioassay for the Burwood effluent and

biosolids samples showed higher toxicity than for the other two types of tests. The IC50 of the

Burwood effluent samples ranged from 17 to 100% (average of 36 %) while the IC50 for biosolids

samples ranged from 17 to 43% (average of 26%). For May 2013, both the effluent and biosolids

samples showed the highest toxicity recorded when compared to the other five sampling events.

Using the most sensitive test species, the NOEC range reported for effluent was between 6.3 and

100% compared to the biosolids range of 6.3 to 25%. In assessing the results, NOEC concentrations

for the biosolids are consistent with findings from ESA (2005) across all three tests. No historical

comparison with the effluent was possible as effluent had not been DTA tested prior to MEAP. The

findings have also reconfirmed that a no effect dilution for both the effluent and biosolids is in the

order of 15:1. Applying a safety factor of two, it is concluded that the minimum required initial dilution

to avoid toxic effects is 30:1.

Toxicity Identification Evaluation (TIE) testing was conducted in order to assess the potential

chemicals causing this toxicity and it was identified that ammonia was the main source of toxicity

observed in the 72 hour microalgal growth assay and the 72 hour sea urchin larval development test,

however results from the November 2012 sea urchin fertilization bioassay confirm that toxicity in

biosolids may not entirely be attributable to the presence of ammonia.

The high concentration of ammonia present in both the effluent and biosolids discharge has the

potential to cause toxicity in the receiving environment. Ammonia has been measured in effluent and

biosolids at median concentrations of 23 mg/L and 24 mg/L, respectively (Hunter Water 2013) and

dilution of the effluent and biosolids outfalls has been modelled to be 100:1 and 200:1 dilution,

respectively (CEE 2010). As the biosolids dilution is normally in the range of 200:1 to 470:1 (CEE

2007), and the dilution of effluent is in the order of 100:1, no toxic effects in the receiving environment

are expected to occur as concentrations of ammonia should be reduced to below the ammonia

ANZECC guideline of 0.91 mg/L for 95% protection of species.

Based on the findings of the MEAP, no direct toxicity has been observed or is likely to occur due to

the level of dilution achieved at the outfalls. The findings from the current batch of testing show that

the NOEC varies between sampling periods and between the test species, which is also consistent

with previous findings.

6.2.1 Implications

Reductions in ammonia concentrations in both the effluent and biosolids remains the most effective

method to reduce the toxicity observed in the testing. However, as the level of dilution achieved in

the receiving environment at both outfalls should be sufficient to mitigate any potential toxic effects it

will be difficult to measure any net environmental benefit from a potential reduction in the amount of

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ammonia discharged to sea. The most likely observable outcome will be in increased compliance of

selected water quality criteria closer to the discharge and reduced toxicity in DTA testing.

6.3 Water quality objectives

There were significant impacts on water quality across a range of variables as a function of distance

from the outfalls. This primarily included ammonia, nutrients (phosphorus and nitrogen) and microbes

(faecal coliforms and enterococci). Enterococci, faecal coliforms and ammonia were significantly

elevated at the outfall zone and in the mixing zone, with a gradient showing a consistent reduction in

concentrations with distance from the outfall. Total phosphorus and total nitrogen concentrations

were elevated in the outfall zone, but not further from the outfalls. Overall, water quality within 500 m

of the Burwood Beach WWTW outfalls does not always meet the ANZECC/ARMCANZ (2000), NSW

Marine Water Quality Objectives (NSW EPA 2000) or NHMRC (2008) guidelines. Due to the offshore

distance, primary contact recreation near the outfalls is not undertaken.

A high magnitude and frequency of exceedances was noted for a number of parameters for many of

the sampling events and this is summarised in Table 4.2 in Section 4. A spatial gradient was also

observed for water quality indicators such as ammonia, total nitrogen, enterococci, chlorophyll a and

faecal coliforms, however the trend was not always apparent for all sampling events.

The strongest patterns in terms of elevated concentrations which decreased with distance from the

outfall were observed for ammonia and enterococci during June 2012 and October 2012.

Concentrations of ammonia and enterococci in June 2012 and October 2012 are shown in Figure

6.4- Figure 6.7.

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Figure 6.4 Ammonia Concentrations, June 2012

Figure 6.5 Ammonia Concentrations, October 2012

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Figure 6.6 Enterococci Concentrations, June 2012

Figure 6.7 Enterococci Concentrations, October 2012

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Biosolids and effluent discharges contain relatively high concentrations of nutrients and moderate

concentrations of metals while the levels of organic chemicals (pesticides) are usually below the limit

of reporting (LOR). The multiple lines of evidence provided by the sediment study, seafood

bioaccumulation study and oyster biomonitoring study show that residual levels of contaminants in the

receiving environment are low and there is no evidence of bioaccumulation, or potential for,

bioaccumulation in marine species.

The sediment study confirmed that higher concentrations of organic carbon were very localized and

within 20m of the outfalls. Similarly, the concentrations of contaminants were slightly elevated within

50m of the outfalls and always less than ANZECC/ARMCANZ (2000) screening levels.

Based on the findings of the MEAP, no adverse effect due to the presence of metals and organic

contaminants has been observed or is likely to occur due to the level of dilution achieved at the

outfalls and the rapid dispersion of organic matter at the point of discharge.

6.3.1 Implications

Reductions in the total loads of nutrients discharged into the receiving environment should have a

positive effect on water quality compliance by reducing the magnitude and frequency of guideline

exceedences in the affected region. This is somewhat dependent also on the volume of effluent and

biosolids discharged, as an exceedance will also be dependent on the dilution achieved.

The elevated ammonia concentration within 500 m of the outfall exceeded the ANZECC trigger level

of 0.02 mg/L which could increase regional phytoplankton growth. However, no local stimulation of

reef biota or infauna due to nutrient discharges was identified in the MEAP.

Findings from the MEAP also confirm that it is currently not possible to distinguish between impacts

form the biosolids and effluent discharge as both contain similar types of contaminants and the main

difference is a higher load of suspended solids in the biosolids. Assessment of surface sediments for

the presence of organic matter and biosolids were inconclusive in identifying deposits directly

associated with discharge of biosolids.

6.4 Sediment Quality

Sewage effluent is a potential source of contaminants in the marine environment which have the

potential to accumulate in the sediments around the point of sewage discharge. Previous studies of

sediment quality at Hunter Water outfalls have been undertaken by Roberts et. al (2007) which

showed no significant patterns that provided evidence of contaminants accumulating in sediments

associated with the discharge of sewage. Concentrations of trace metals detected within the

sediments at the outfall and reference locations were all below the ANZECC (2000) guidelines and

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concentrations of PAH were less than their respective limits of reporting. Samples collected were

primarily sand with a very low content of fine sediment (~3%). The outfall is located in a high energy

environment and Roberts et. al (2007) postulated that significant amounts of disturbance to bottom

sediments must occur at various times and that physical processes may cause contaminants

previously bound in the sediments to become resuspended, redistributed or dissolved back into the

water column, increasing their biological availability (Long et al. 2005).

The MEAP has considered this issue in detail and focused on assessment of risk associated with

elevated levels of TOC that may be associated with biosolids discharge and the presence of metals

that would preferentially associate with fine sediment and particulate.

Monitoring confirmed that TOC present is associated with the biosolids discharge and can be

detected within 20 m of the outfall. None of the 18 metals tested were found to exceed the ANZECC

(2000) ISQG low impact guideline levels with the exception of one sample taken at 20NE (in October

2012), which had a high concentration of antimony.

6.4.1 Implications

Within about 50 m from the outfall there are significantly higher concentrations of metals and TOC

relative to elsewhere. These concentrations however are very low compared to the ANZECC (2000)

ISQG low impact guideline levels. As they do not exceed the guideline levels, metals that are bound

to the bottom sediments do not present a risk to benthic marine species. Similarly, as the loads in the

sediment are also low and processes that resuspend sediment into the water column occur on a

regular basis, the risk of exposure of marine species to metals mobilised in the water column is also

considered low.

Based on the findings of the MEAP, the combination of wastewater treatment, dispersion and dilution

is effective in preventing organic carbon accumulation in the Burwood Beach receiving environment at

distances greater than about 50 m and also reducing the potential for cumulative impacts resulting

from ongoing discharge of metals in the effluent and biosolids.

6.5 Marine Infauna

Trends in abundance, richness and diversity were inconsistent and no gradient of effect was

detected. The use of a polychaete ratio to detect a response associated with organic loading found

some evidence of a higher polychaete ratio within 20m of the outfalls during three of the four survey

periods.

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6.5.1 Implications

The absence of a large footprint of an enriched zone of infauna around the outfalls also provides

additional evidence that organic matter associated with discharge of biosolids does not accumulate

on the seabed. Sludge deposits have been observed in caves adjacent to the biosolids diffuser

during previous inspections (CEE 2007) and divers have noted a fine layer of silt around the outfall,

however no long term accumulation of biosolids has previously been noted.

The MEAP has provided additional evidence that particulate associate with biosolids discharge does

not accumulate and is transported away from the discharge point quite rapidly. A thin layer of detritus

collected in a grab sample during a survey concluded that the proportion of biosolids was minor and

that much of the material was of marine origin.

Fine scale sampling of surface sediments and testing of TOC also confirmed that elevated TOC was

confined to an area within 20m of the outfalls. Similarly, concentrations of selected metals are

elevated within 50m of the outfalls but well below recommended ANZECC (2000) sediment quality

guidelines. As bioavailability of most contaminants is strongly influenced by grain size and metals

have an affinity for the finer particle fractions (<63 µm), the presence of low concentrations of

contaminants also provides further evidence that discharge from the outfalls is not cumulative.

The presence of a very localized area of polychaete enrichment that is only present on a temporary

basis also provides evidence of the transient effects the current discharge of effluent and biosolids

has on the infaunal community.

6.6 Reef Communities

The reef community around the outfalls is dominated by a very low diversity of flora and fauna. Total

algae are nearly entirely comprised of one form of red algae (coralline species) and the presence of

an "unknown" classification of taxa that is comprised of microflora and fauna, silt and mico-organisms.

There is a larger proportion of this classification of habitat close to the outfalls compared to the

reference sites which has been recorded during previous survey periods. Total abundance, richness

and diversity of fauna were also variable between sites and sampling periods showing no consistent

trends.

The overall low abundance of flora and fauna is likely related to the high energy environment and

sand movement whereby many species are unable to establish or recover from sand smothering.

The lack of reef habitat and potential edge effects on some patchy reefs has also shown to be a

limitation to allow interpretation of the data.

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6.6.1 Implications

Overall, there is no consistent pattern in flora or fauna abundance, richness or diversity which allows

an impact from the discharge of either effluent or the biosolids to be identified. The presence of the

"unknown" classification across all sites including reference sites also suggests that its occurrence is

not directly related to discharge from the outfalls.

The discharge of effluent and biosolids may be expected to result in some change in the abundance

and composition of the reef communities however this cannot be quantified due to the larger impact

caused by natural disturbance related to sand inundation. On this basis, it is unclear if an increase in

the volume or quality of effluent or biosolids discharged will have a significant impact on the reef

community adjacent to the outfalls.

6.7 Fish Assemblages

Underwater visual census and BRUVS has confirmed significantly higher fish abundance at the outfall

sites in comparison to the mixing zone and reference zone. Higher abundance around the outfalls is

most likely attributed to the increased level of nutrients and particulates that provide a source of food.

Trends in species richness and diversity were less apparent although the results of the assessment

have also been affected by the lack of equivalent reef habitat at other locations inside the mixing zone

and reference areas making direct comparisons difficult.

6.7.1 Implications

The presence of a higher abundance of fish around the outfall can be directly related to the discharge

from the outfalls. Results for richness and diversity are inconsistent, with some evidence of

significantly higher species richness at the outfall zone using UVC and lower species richness using

BRUVS.

A reduction in the level of biosolids discharged is likely to result in a decline in the abundance of fish


6.8 Assessment of Current Performance

No large scale or regional effects were observed during the MEAP as biological effects were subtle

and localised. The most obvious effect from the discharge is the biosolids plume which was visible

during all of the sampling periods.

Figure 6.8 and Figure 6.9 provide a schematic representation of the inferred impact zone around the

outfall based on actual measured concentrations of ammonia and enterococci measured in June

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2012. The zone is not a fixed area but instead will vary depending on a number of factors including

the volume of effluent flow, the volume of biosolids discharged and the prevailing metocean

conditions during each particular day. The volume of bypass flow will also have a significant impact

on the zone for these two respective indicators.

The zones can also be categorised into a zone of significant impact which is strongly localized around

the discharge and within 30m of the discharge. A second zone, the zone of detectable impact is also

shown and extends between 250 to 500 m from the discharge.

It is also worth noting that only the waters in the diluted plume contain elevated levels of ammonia or

enterococci and the remainder of the water within the inferred impact zone should be at or near

ambient concentrations. However the position of the plume changes with variations in the current

direction and over a period the whole of the defined impact zone may be impacted at times.

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Figure 6.8 Inferred impact zone based on monitoring of ammonia in the Water Quality Study

during June 2012.

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Figure 6.9 Inferred impact zone based on monitoring of enterococci in the Water Quality Study

during June 2012.

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Based on the analysis of monitoring results from each of the studies completed as part of the MEAP,

the following effects were noted at the Burwood beach outfalls:

Extensive water sampling showed that concentrations of ammonia, total nitrogen, total phosphorus, enterococci and faecal coliforms are higher at outfall and decreased with distance from outfalls. The effects of outfalls on water quality were detectible to 500 m from outfalls.

Some elevated levels of contaminants have been noted in sediments within 50m of the outfalls,

however concentrations are well below interim sediment quality guidelines and no toxic

effects are likely to occur.

Some elevated levels of organic carbon have been noted within 10m of the outfalls which may

be attributable to the presence of biosolids on the seabed but could not be determined from

limited sampling of material.

DTA testing of both effluent and biosolids show a range of toxic responses that vary between

the species tested and also between sampling periods. Ammonia was shown to be a

significant contributor to the observed toxicity in two of the three tests during laboratory

testing, however the concentrations likely in the receiving environment are unlikely to be toxic

due to the high level of dilution and mixing achieved.

No evidence of impacts on the flora and fauna of reefs near the outfalls, although this was

difficult to quantify and distinguish from natural caused variability.

Possible minor effects on infauna through some evidence of polychaete dominance within 20m

of the outfalls. Inference is weak due to significant seasonal and spatial variability.

No evidence of bioaccumulation of tested organic chemicals or metals that can result in

impacts on marine biota or increased risks to human health through ingestion of

contaminated seafood such as oysters and locally sourced fish.

Some elevated levels of microbial indicators in some seafood caught around the outfall, which

has been assessed by the NSW Food Authority (NSW FA) as presenting a low risk.

It is very difficult to differentiate between impact associated with the biosolids discharge and the

discharge of effluent.

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Summary

A summary of the current performance of impacts from Burwood Beach WWTW is provided in Table

6.2.

Table 6.2 Summary of Environmental Impact Assessment based on MEAP Results

Impacts Assessed Evidence from MEAP Outcome

Water Quality Effects Extensive sampling showed that concentrations of ammonia, total nitrogen, total phosphorus, enterococci and faecal coliforms are higher at outfall and decreased with distance from outfalls. Effects of outfalls on water quality were detectible to 500 m from outfalls.

High ambient nitrogen at outfalls and at reference sites.


Toxicity Effects Extensive testing of toxicity showed that biosolids is somewhat more toxic than effluent. Ammonia is the principal cause of toxicity in two of the three tests but noted that there may be additional factors at times. Initial dilution should be sufficient to have no toxic effect from effluent or biosolids in the receiving waters, as present dilution reduces levels to below the ANZECC (2000) guideline for ammonia for 95% protection of species.

NO IMPACT in receiving waters due to high dilution


Consistent increase in TOC in sediments within 20 m of diffusers, largely attributed to high amount of solids in biosolids.

LOCAL IMPACT – can detect higher TOC in sediments within 20 m of diffusers


No accumulation of pesticides (OC, PCB and OP) in sediments. Some metals slightly elevated in sediments near outfall (copper, zinc, barium, lead, mercury) although all metal levels less than ANZECC (2000) low impact guidelines.


Infauna Community Large natural variability in infauna populations and thus difficult to detect any consistent change in community structure. Likely that the higher TOC supports higher polychaete population within 20 m of outfalls.


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Reef Flora and Fauna Reefs at and near outfalls are low profile and subject to sand abrasion in storms and occasional inundation by sand. Small number of pioneer species found, with low abundance, richness and diversity, Natural stresses likely overwhelm any effect caused by discharges.

NO IMPACT detected on reef communities in relation to high natural stresses

Fish Increased abundance of fish at the outfalls, although diversity and richness the same at outfall sites and reference sites. Thus fish attracted to food in discharges and rising plumes are a fish “attractor”.

LOCAL IMPACT – can detect more fish within 25 to 50 m of diffusers


Oyster biomonitoring study found similar concentrations of metal and organic contaminants at outfall sites, mixing zone sites and reference sites. Thus inputs from the land and ambient background are larger than any effect of the outfalls.

No accumulation of pesticides (OC, PCB and OP) in fish.

NO IMPACT detected


About 10 to 20 per cent of Yellowtail caught at outfalls had elevated faecal coliforms and E. coli in edible fillets, which was likely to be in the skin.

LOCAL IMPACT – fish must be cooked

Bathing Water Quality Elevated levels of faecal coliforms and enterococci detected to 500 m from diffusers.


Plume Visibility Plume generally visible from boat above outfall LOCAL IMPACT

6.9 Projections of Future Effects

6.9.1 Increased Flows and Loads

Under current projections, dry weather total effluent and biosolids discharge from the Burwood Beach

WWTW is expected to increase from around 44 ML/day to 54 ML/day by 2040, corresponding to a 23

per cent increase in effluent, with a corresponding increase in the amount of biosolids

discharged. Assuming that additional treatment capacity is provided but there are no process

upgrades (baseline scenario), the increase in discharge of effluent and biosolids is likely to result in

an increase in the zone of detectable impact in the receiving environment.

The actual extent of impacts will depend on several factors, including the reduction in initial dilution

with increased discharge, any changes to the number and characteristics of discharge ports and the

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future patterns in other processes affecting conditions in the receiving environment (frequency of

storms, flood inputs from the Hunter River, sand movements, and other inputs of contaminants).

Evidence from other outfalls elsewhere in Australia with much larger volume discharges, e.g. at

Sydney and Boags Rocks, shows that the zone of detectable impact is mostly influenced by

metocean conditions and outfall location and design, with observable effects over a small area

(Sydney, with deepwater outfalls) or a large area (Boags Rocks with a shoreline discharge). The

situation at Burwood Beach is closer to the conditions at Sydney than at Boags Rock, as the outfalls

are in 22 m water depth (and achieve a high initial dilution) in a region with strong longshore currents

and regular oceanic storms.

Projected Water Quality Effects

Assuming that the future discharges are made in similar metocean conditions as occurred during the

two-year MEAP, the extent of detectible effects of water quality is projected to increase from about

500 m distance from the outfalls at present to about 600 m from the outfalls in the future.

Projected Toxicity Effects

The MEAP carried out extensive testing of toxicity of the effluent and the biosolids and found that

biosolids were more toxic than effluent, with ammonia being the principal constituent causing the toxic

response in two of three tests. Thus the toxicity impact in the receiving waters depends largely on

ammonia levels in the discharges and initial dilution. Under current flows and the existing diffusers,

the initial dilution is sufficient to reduce levels to well below the ANZECC (2000) toxicant trigger of

0.910 mg/L for ammonia. With the increased discharges, the initial dilution is expected to decrease

by about 10 per cent (CEE, 2013) which should still be sufficient to reduce levels to below the

guideline, with a slightly smaller but still adequate margin of safety.

Projected Effects on Sediments and Infauna

The MEAP found that there was a consistent increase in TOC in sediments within 10 to 20 m of the

diffusers (0.5 to 2 % TOC compared to < 0.5 % TOC elsewhere), largely attributed to the discharge of

solids in the biosolids. Because of the large natural variability in infauna populations, it was difficult

to detect a change in the community structure or abundance of infauna, although there was an

occasional indication of higher polychaete populations within 20 m of the outfall, which would be

expected to correlate with the higher TOC levels. Taking a conservative approach to predictions of

impacts with increased flows, it is expected that the area with higher TOC could increase to 20 to

30 m from the diffusers, and a higher number of polychaetes could be found within this zone.

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Projected Effects on Reef Flora and Fauna

Reefs in the area of the Burwood Beach outfalls extend only a metre above the level of the adjacent

sandy seabed and are subjected to sand abrasion in most storms and occasional inundation by sand.

Although not specifically measured, anecdotal evidence from historical surveys indicates that this

process may occur at intervals of one to two years. Thus the reefs have a low number of flora and

fauna species, with low abundance, richness and diversity. The MEAP found no consistent gradient

in reef biological conditions with distance from the outfalls and no effects that could be attributed to

the discharges.

In this situation where natural stresses tend to overwhelm any effects caused by the discharges, it is

expected that there would be no detectible effect of the increased discharges on reef communities.

Projected Effects on Fish

The MEAP found that there are more fish at the outfalls, attributable to increased abundance of

species which naturally inhabit the region. Fish species richness and diversity was much the same at

the outfalls and the reference sites, which indicates that fish are attracted to the outfalls likely due to a

source of the food in the discharge and also by the refraction patterns of the plumes (fish are

attracted to discharge sites even if there is no extra food).

The majority of the food is contained in the biosolids in the form of total suspended solids and thus

the biosolids discharge may be a greater attraction for fish that the effluents discharge, although this

is speculation. It is projected that with increased discharge there would continue to be more fish at

the outfalls – it may not be that the extra food would actually attract more fish, as there may already

be “excess” food in the discharges.

Projected Effects on Oyster and Fish Bioaccumulation and Contamination

The MEAP conducted oyster and fish biomonitoring studies and concluded that concentrations were

similar at the outfall in comparison to other sites. Thus it appears that the change in concentrations

and loads of contaminants in the outfall discharges, relative to inputs from land runoff and ambient

levels, does not result in a detectible bioaccumulation of contaminants in oysters or fish.

The actual increase in the load of organic and metal contaminants discharged in the future may not

necessarily increase in proportion to the increase in discharge, depending on the stringency of source

control and the behaviour of people living in the catchment area. However, it might be anticipated

that there will be some increase in discharge of contaminants in the future, which should be reflected

in some minor increase in loads to the environment. Even if this occurs in direct proportion to the

increase in discharges, it is expected that fish caught in the region should remain well within safe

limits of metal and organics for human consumption.

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The MEAP established that about 10 to 20 per cent of yellowtail caught at the outfall had elevated

levels of microbial indicators (faecal coliforms and E. coli) in the skin. This impact is expected to

continue into the future with continued discharge of effluent and biosolids at greater rates. It is

possible that there will be no increase in the number or proportion of fish affected, although this is

speculative as the mechanisms for transfer, accumulation and die-off are not known. NSW Health

consider that the appropriate control is to avoid fishing in waters affected by sewage. It might be the

case that this impact is more correlated to the biosolids discharge than the effluent discharge, as fish

caught at the Boulder Bay outfall (where there is no biosolids discharge) were not affected. It could

also be possible that this is related to by-pass flows, as Burwood Beach WWTW has much higher by-

pass flows in comparison to Boulder Bay WWTW. The extent of microbial contamination was also

much lower during the one sampling event which had no by-pass flows, in comparison to the other

three sampling events, where there was a high amount. If related to the effluent (refer below) then

disinfection is expected to reduce microbial exposure.

Projected Effects on Bathing Water Quality.

The QMRA conducted prior to the MEAP provided a detailed assessment of the risks to bathing water

from the current discharges. Events with potentially elevated pathogen levels in bathing and surfing

waters correspond to low stratification, prolonged onshore currents, and prolonged onshore winds.

For bathers in summer, the exceedance probability of a gastrointestinal illness was 0.05 to 0.08 (for

comparison, the exceedance probability is 0.01 for a visit to the beach with no swimming). For

surfers, the exceedance probability was higher at 0.02 to 0.05 owing to the longer exposure period

and their activities continuing in winter and in early mornings.

Hunter Water is addressing this risk through disinfection of the effluent, which is the principal source

of indicator organisms of the two discharges. With disinfection implemented, increased discharges

should have no effect on the risks, which would be substantially reduced.

Summary

A summary of the projected effects from the scenario of an increase in flows and loads from Burwood

Beach WWTW is provided in Table 6.3.

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Table 6.3 Summary of Environmental Impact Assessment for Scenario – Increase in

Discharges by 23 % to year 2031.

Impacts Assessed Outcome from MEAP – present discharges of 44 ML/d of effluent (dry weather) and 4.5 ML/d of WAS

Predicted outcome – Higher Flows (23 % increase in effluent and WAS discharges)

Water Quality Effects


LOCAL IMPACT – projected to be able to detect increase in water quality parameters to 600 m from outfalls

Toxicity Effects NO IMPACT in receiving waters due to high dilution

NO IMPACT in receiving waters due to high dilution- remain the same


LOCAL IMPACT – can detect higher TOC in sediments within 20 m from diffuser

LOCAL IMPACT – projected to extend to 30 m from diffuser



LOCAL IMPACT – projected higher metals in sediments within 60 m of diffusers

Infauna Community POSSIBLE LOCAL IMPACT – more polychaetes within 20 m of diffusers


Reef Flora and Fauna


NO IMPACT – projected to remain the same

Fish LOCAL IMPACT – can detect more fish within 25 to 50 m of diffusers

LOCAL IMPACT – more fish within 25 to 50 m of diffusers- but the same as now.


NO IMPACT detected NO IMPACT expected


LOCAL IMPACT – 10 to 20 % of fish contaminated and fish must be cooked

LOCAL IMPACT – projected to remain the same

Bathing Water Quality

LOCAL IMPACT –to 500 m from outfalls LOCAL IMPACT –projected to extend to 600 m from outfalls unless there is disinfection of discharges

Plume Visibility LOCAL IMPACT LOCAL IMPACT – expected to be visible over the same local area

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6.9.2 Reducing Biosolids Discharge

With the current monitoring program, it has been difficult to distinguish between impacts associated

with the biosolids and the sewage effluent. The most likely impact associated with the biosolids on

benthic habitat is the elevated organic carbon in sediments found close to the outfalls, which is often

associated with biosolids particulates. The proportion of TOC diminishes rapidly with distance from

the outfalls, resulting in a very subtle impact on infaunal communities.

Due to the number and variability of sewage biosolids constituents, it is often difficult to detect

consistent effects on biota in the field, however field studies which have examined the effects of

sewage on system response have indicated that nutrients, rather than toxicants have the dominant

effect (Oviatt et al. 1987). Similarly, if impacts from discharge of sewage biosolids are significant,

they would be most likely detected by monitoring of infauna. Typical responses include severe

inhibition of the total benthic assemblage, domination and large density increases in a few species or

increased density of virtually all indigenous species with zonation apparent in response to biosolids

loading rates.

Findings from the current MEAP have found no evidence of severe inhibition on infauna and no large

density changes in abundance or diversity. However, the high level of variability found in the infauna

study also contributed to difficulty in detecting differences (i.e. there was insufficient power to

statistically detect differences). There is some evidence of response in polychaete numbers within

20 m of the outfall.

The most "observable" impact associated with the biosolids discharge is the visible plume which

attenuates light through the water column and also affects visual amenity. Divers have reported a

fine layer of silt around the outfall although the source of this matter could not be confirmed through

collection of a single grab sample which showed that it was composed of mostly marine matter. The

fact that more significant accumulation of silt has not been observed around the outfalls seabeds is

likely to be a combination of the hydrodynamic conditions and volume of biosolids discharged. It is

likely that the prevailing hydrodynamic conditions at the outfall site are efficient at dispersing and

diluting the biosolids and that the volume of biosolids discharged is not significant compared to the

total volume of effluent discharged.

Based on current volumes discharged and the results of the MEAP, reducing or eliminating the

volume of biosolids discharged to the ocean is unlikely to result in any measurable improvements in

the ecological condition of the marine habitats around the discharge. However, there are likely to be

significant improvements in visual amenity due to a reduction in the suspended solids discharged and

increased compliance to water quality guidelines, due to a reduction in the levels of nutrients, and

primary contact recreation objectives, due to the a reduction in the presence of enterococci and

faecal coliforms in the water column. It is also possible that the risk of microbial contamination of

seafood will also be reduced.

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Summary

A summary of the projected effects from the scenario of reducing biosolids discharge from Burwood

Beach WWTW is provided in Table 6.4.

Table 6.4 Summary of Environmental Impact Assessment for Scenario– Change from Ocean

Discharge of biosolids to Land Recycling

Impacts Assessed Outcome from MEAP – present discharges of 44 ML/d of effluent (dry weather) and 4.5 ML/d of biosolids

Predicted outcome – Recycle biosolids to Land with No Ocean Discharge of biosolids but same effluent treatment

Water Quality Effects LOCAL IMPACT – can detect local increase in water quality parameters to 500 m from outfalls

LOCAL IMPACT – projected to be able to detect increase in water quality parameters to 600 m from outfalls as most nutrients are in the effluent




LOCAL IMPACT – can detect higher TOC in sediments within 20 m from diffusers

LOWER IMPACT – expect no detectible change in TOC in sediments



LOWER IMPACT – expect no detectible change in metals in sediments


LOWER IMPACT – no detectible infauna changes



NO IMPACT – projected to remain the same


LOCAL IMPACT – but remain the same - more fish within 25 to 50 m of diffusers

Bioaccumulation in Oysters and Fish


Micro-biological LOCAL IMPACT – 10 to 20 % of fish LOCAL IMPACT – risk of

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Contamination contaminated and fish must be cooked contamination reduced, particularly in combination with disinfection of discharges



LOCAL IMPACT –projected to extend to 600 m from outfalls unless there is disinfection of discharges


6.9.3 Reducing Nutrient Discharges

As mentioned previously, it has been difficult to distinguish between environmental impacts

associated with discharge of biosolids and effluent. Discharge of large quantities of nutrients into

coastal waters can cause increased primary productivity leading to blooms of phytoplankton and

macroalgae. Other issues related to excessive nutrient discharge can include dissolved oxygen

depletion, bioaccumulation of organic and inorganic compounds and potential alteration of trophic

interactions. Findings from the current MEAP have found no evidence of any of these potential

impacts in any of the studies completed. There has also been no documented or anecdotal evidence

of localised algal blooms having occurred along this section of coastline in the past which would have

likely been related to the outfall.

Of additional significance is that other sources of nutrients, such as terrestrial runoff from the Hunter

catchment, and natural processes such as upwelling events are common within the region and also

have the potential to contribute as sources of nutrients.

The discharge of nutrients in the effluent is resulting in a localised increase of corresponding water

quality parameters around the outfall. While the concentrations of nutrients (in the form of ammonia,

total nitrogen and total phosphorus) in the effluent and biosolids are very similar, the total loads

discharged are significant higher through the effluent stream. Environmental impacts from discharge

of these nutrients are not evident in the receiving environment and this is most likely attributable to a

combination of the following factors:

prevailing hydrodynamic conditions at the outfall site are efficient at dispersing and diluting the

effluent;

the volume of nutrient (effluent) discharged is not significant compared to other much large

coastal outfalls that operate elsewhere in NSW (such as Sydney);

the receiving environment is subject to existing natural stressors that mask any lesser impacts

resulting that result from the discharges.

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Based on current volumes discharged and the results of the MEAP, reducing the concentration of

nutrients discharged to the ocean is unlikely to result in any measurable improvements in the

ecological condition of the marine habitats around the discharge. However, there are likely to be

significant improvements in water quality, due to the reduction in the amounts of ammonia and

nitrogen being discharged into the marine environment.

Summary

A summary of the projected effects from the scenario of reducing ammonia and nitrogen discharges

from Burwood Beach WWTW is provided in Table 6.5.

This scenario is a combination of two upgrades involving (1) installation of biological nutrient removal

(BNR) and (2) disinfection of effluent. The benefits associated with installation of BNR should be an

improvement in water quality with lower levels of ammonia and total nitrogen in the outfalls zone but

possibly only able to be detected to 100 m from the outfalls. In comparison, the benefits of

disinfection of effluent are more significant and should be lower impacts on water quality over to 500

m from the outfalls and in seafood as a result of lower levels of enterococci and faecal indicators.

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Table 6.5 Summary of Environmental Impact Assessment for Scenario– Install Biological

Nutrient Remover (BNR) to Reduce Ammonia and Nitrogen Discharges and Disinfection

Impacts Assessed

Outcome from MEAP – present discharges of 44 ML/d of effluent (dry weather) and 4.5 ML/d of biosolids

Predicted outcome – Higher Flows with Lower Ammonia and Nitrogen Discharges and Disinfection

Water Quality Effects


LOWER IMPACT – possibly will only be able to detect increase in water quality parameters to 100 m from outfalls




LOCAL IMPACT – can detect higher TOC in sediments within 20 m from diffusers

LOCAL IMPACT – projected to extend to 30 m from diffusers



LOCAL IMPACT – projected higher metals in sediments within 60 m of diffusers





LOCAL IMPACT – projected to remain the same


LOCAL IMPACT – but remain the same - more fish within 25 to 50 m of diffusers

Bioaccumulation in Oysters and Fish



LOCAL IMPACT – 10 to 20 % of fish contaminated and fish must be cooked

LOWER IMPACT – should not be able to detect elevated enterococci or E Coli levels due to disinfection



LOWER IMPACT –should not be able to detect elevated enterococci or E Coli levels due to disinfection


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7. CONCLUSIONS

The MEAP began in June 2011, and was completed in September 2013. The integration report has

provided an assessment of the environmental impact and the current environmental performance of

the Burwood Beach discharge as it affects the receiving waters and their associated ecosystems.

A summary of the observed impacts or patterns related to distance from the outfalls from all the

component monitoring programs is outlined in Section 4. These show that monitoring indicator

response is variable, with some programs showing a clear ecological response while others are less

definitive. The variability in the results reflects the interactions and complexity of the ecosystem. In

general, the results noted during the monitoring program, apart from the water quality monitoring

program, were neither consistent between sampling periods or between sites, along the defined

gradient. i.e. while trends were apparent for some of the monitoring variables, the spatial and

temporal variability observed also masked any consistent trends in some studies.

The water quality results indicate a zone of detectable impact extending to about 500 m from the

outfalls. Water quality within 500 m of the Burwood Beach WWTW outfalls does not always meet the

guidelines. Enterococci, faecal coliforms and ammonia were significantly elevated at the outfall zone

and in the mixing zone, with a gradient showing a consistent reduction in concentrations with distance

from the outfall. Faecal coliforms and enterococci seldom met the NSW Marine Water Quality

Objectives (NSW EPA 2000) for primary contact recreation. Total phosphorus and total nitrogen

concentrations were elevated in the outfall zone, but not further from the outfalls. Concentrations of

ammonia and total nitrogen at times exceeded the ANZECC/ARMCANZ (2000) ecological guidelines.

Ecotoxicology testing showed toxicity of effluent and biosolids at concentrations ranging from 12.5-

50% dilution in all measured direct toxicity assessments (DTA) tests and further investigations

confirmed that the major cause of effluent toxicity was ammonia.

The lack of consistent findings within the sediment quality assessment confirms that the effluent and

biosolids are mixed fairly rapidly and does not accumulate in the vicinity of the discharge point for any

extended duration.

With regard to nutrient loads from the outfalls, the study was not able to make any definitive

identification of impacts, apart from fish, in the receiving environment due to elevated nutrient levels.

Apart from non-compliance with the relevant water quality objectives, it is unclear how this relates to

changes identified in other ecological communities.

Bioaccumulation studies in oysters and fish showed that there was little evidence of bioaccumulation

of the tested metals in organisms from Burwood Beach in comparison to reference locations. The

oyster study detected low concentrations of organochlorines in one sampling event, suggesting

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presence around the outfalls. The seafood bioaccumulation study found elevated levels of

thermotolerant coliforms and E. coli in a proportion of yellowtail scad and snapper, fish that are

commonly fished, in particular by commercial fisherman, around the Burwood Beach outfalls. On

average, E. coli levels in fish from Burwood Beach consistently exceeded the NSW FA (2001)

guideline for ready to eat food, although this would only be applicable where seafood is consumed

raw. Advice from NSW Food Authority (NSW FA) to Hunter Water regarding the microbiological

results indicated that the associated burden of disease appeared to be low which implied the level of

risk was low. This was seen as being consistent with factors identified regarding typically small catch.

Fish are rarely consumed raw and there were low and sporadic E. coli levels, with pathogen levels

being lower again.

The anticipated response in infaunal communities from organic enrichment of sediments caused by

the discharge of biosolids particulates was not conclusive. An increase in the polychaete ratio was

noted, however the inference was weak as the increase was not consistent across sampling periods

and was also limited spatially to within 20m of the discharge. Other responses noted were the

increase in the numbers of fish around the discharge and the changes in reef species assemblages


The use of the gradient based design in assessing potential impacts has provided advantages over a

conventional "before and after" comparisons which are primarily concerned with identifying

statistically significant trends which may or may not be ecologically significant. The latter has been

addressed in the study by applying multiple lines of evidence to interpretation of the results

supplemented by in situ based observations in the field. The full extent of the effluent and biosolids

impact remain somewhat elusive, partly due to the diffuse nature of the impact but primarily due to the

large amount of spatial and temporal variation observed across many of the monitoring variables, and

the high natural stresses on the reef and infauna communities.

The issue of suitable control sites with which to compare the extent of impact also provided the

potential for confounding. This has been raised with respect to the water quality monitoring program,

whereby the footprint of impact was seen to extend to beyond 500 m for some parameters, but was

less problematic with other aspects of monitoring. It can be argued however that the existing

monitoring results have provided clear evidence of impact around the outfalls but any impacts on

ecological values become less discernible beyond 50m of the outfalls and 500m for water quality.

Furthermore, the results from the current monitoring program are not dissimilar to findings from the

historical monitoring programs undertaken at this location.

In the case of the infauna and reef studies, marked temporal and spatial variability made it difficult to

detect clear trends and characterise the extent of impact and whether it is increasing. The Burwood

Beach outfalls are located in a high energy environment with intermittent sand movement. This is

likely to act as a disturbance mechanism and influence the structure of benthic communities. This

issue has been identified by previous consultants working on the Burwood Beach outfalls. These

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temporary reef environments are unlikely to maintain stable flora and fauna communities. Instead,

reef communities are likely to be in a permanent state of heterogeneous flux, with decline in areas of

deposition and colonization/recovery on newly exposed reef in areas of erosion. This would, to some

extent, explain the high spatial and temporal variability observed in both current and previous studies;

however it also hinders the detection of any impacts.

From a water quality perspective, an increase in volume of discharge without any improvements in

treatment will continue to increase the frequency of non-compliance associated with ammonia,

enterococci and faecal coliforms and most likely also increase the spatial extent of non-compliance.

Similarly if the basis of current non-compliance is around protection of beneficial uses, then any

changes to treatment should focus on removal of ammonia and pathogens (through disinfection).

This will produce an overall benefit of reducing the overall nutrient load to the receiving environment

and further reduce any risk to human health. It should be noted however, that for any changes in

treatment, it will continue to be difficult to measure a change in the condition for some of the

ecological indicators, e.g. reef and infauna, as a result of these improvements due to the variability

observed to date.

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AWT (2000). Benthos Survey at Boulder Bay and Burwood Beach Wastewater Treatment Works

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CEE (2007). Environmental Monitoring and Performance Review of Burwood Beach WWTW Biosolids

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Appendix 1 – Summary of Chemistry

Compliance Monitoring

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Summary of physicochemical, nutrients, metal/metalloid and organics data in effluent collected by Hunter Water during 2006 - 2013.

Group Parameter (units) Period N Median Mean Min Max Std

Error 75%ile 90%ile

Physicochemical

Suspended solids (mg/L) 2006-13 449 27 33.6 <1 390 1.6 40 60

UV254nm Transmittance (%T) 2006-13 6 59.2 58.4 43.6 68.31 3.4 62.475 65.705

pH 2006-13 224 7.6 7.6 7 8 0.01 7.7 7.8

Total dissolved solids (mg/L) 2006-13 56 440 448.5 276 734 12.9 487.5 545

Biological Oxygen Demand - total (mg/L) 2006-13 239 23 27.4 <2 144 1.3 36 50

Chemical Oxygen Demand - Flocculated (mg/L) 2006-13 19 42 41.8 32 55 1.6 46 51.4

Grease - total high range (mg/l) 2006-13 3 <5 4.7 <5 10 2.7 6 8.4

Grease - total low range (mg/l) 2006-13 444 <2 2.7 <2 60 0.2 3 5

Ammonium nitrogen (mg/L) 2006-13 70 23.0 21.7 1 33.1 0.8 26.8 29.4

Nitrate + nitrate nitrogen (mg/L) 2006-13 236 1.0 1.6 <0.05 14 0.1 2.1 3.7

Total Kjeldahl Nitrogen (mg/L) 2006-13 236 26.9 26.1 2.2 48.7 0.6 33.0 36.9

Total nitrogen (mg/L) 2006-13 236 28.7 27.6 2.45 48.7 0.6 33.6 37.7

Total phosphorus (mg/L) 2006-13 236 2.3 2.64 0.09 8.2 0.11 3.625 4.8

Metals / Metalloids

Silver-Ag-AAS furnace (µg/L) 2006-13 31 1 3.1 <1 18 0.9 2.5 13

Silver Ag-ICP (µg/L) 2006-13 59 0.5 0.7 <1 7 0.1 0.5 1

Arsenic As-vga (µg/L) 2006-13 90 1.7 1.8 0.05 3.9 0.1 2.1 2.51

Cadmium Cd-furnace (µg/L) 2006-13 5 <1 <1 <1 <1 - <1 <1

Cadmium Cd-ICP (µg/L) 2006-13 59 <1 0.5 <1 1 <1 <1 <1

Chromium Cr-furnace (µg/L) 2006-13 31 1 1.9 <1 28 0.9 1.2 2

HUNTER WATER


BURWOOD BEACH WWTW



Error 75%ile 90%ile

Chromium Cr- ICP (µg/L) 2006-13 59 <1 0.7 <1 2 0.1 0.75 1

Chromium Cr VI-furnace (µg/L) 2006-13 90 <1 0.7 <1 1 - 1 1

Copper Cu-furnace (µg/L) 2006-13 31 17 21.2 4 115 3.5 21 34

Copper Cu-ICP (µg/L) 2006-13 93 0.25 0.4 0.04 1.7 - 0.47 0.728

Mercury Hg-VGA (µg/L) 2006-13 90 <0.1 0.1 <0.1 1.6 - <0.1 0.2

Manganese Mn-furnace (µg/L) 2006-13 31 70 76.0 31 173 6.6 82 105

Manganese-ICP (µg/L) 2006-13 59 61 63.8 27 119 2.0 67.5 80.2

Nickel Ni-furnace (µg/L) 2006-13 90 <1 <1 <1 <1 - <1 <1

Nickel Ni-ICP (µg/L) 2006-13 59 4 5.3 <1 20 0.6 5.5 13.2

Lead Pb-furnace (µg/L) 2006-13 90 3 3.1 <1 17 0.3 4 5

Selenium Se-VGA (µg/L) 2006-13 90 0.1 0.3 <0.1 2 - 0.4 0.6

Zinc Zn (µg/L) 2006-13 31 50 49.4 10 120 4.3 55 70

Zinc Zn-ICP (µg/L) 2006-13 59 24 31.2 4 164 3.2 35 55.8

Organics

Aldrin (µg/L) 2006-13 90 <0.01 <0.01 <0.01 <0.01 - <0.01 <0.01

α-BHC Bhc-a (µg/L) 2006-13 90 <0.01 <0.01 <0.01 <0.01 - <0.01 <0.01

β-BHC-b (µg/L) 2006-13 90 <0.01 <0.01 <0.01 <0.01 - <0.01 <0.01

α Chlordane (µg/L) 2006-13 90 <0.01 0.000 <0.02 0.003 - <0.01 <0.01

Chlordane (µg/L) 2006-13 90 <0.01 0.001 <0.02 0.020 - <0.01 <0.01

λ Chlordane (µg/L) 2006-13 11 <0.01 0.000 <0.02 0.001 - <0.01 <0.01

Chlorpyrifos (µg/L) 2006-13 90 <0.01 0.007 <0.05 0.629 0.007 <0.01 <0.01

Lindane (µg/L) 2006-13 90 <0.01 0.000 <0.01 0.005 - <0.01 <0.01

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BURWOOD BEACH WWTW



Error 75%ile 90%ile

DDT (µg/L) 2006-13 90 <0.01 <0.01 <0.01 <0.01 - <0.01 <0.01

DDD (µg/L) 2006-13 90 <0.01 <0.01 <0.01 <0.01 - <0.01 <0.01

DDE (µg/L) 2006-13 90 <0.01 <0.01 <0.01 <0.01 - <0.01 <0.01

Diazinon (µg/L) 2006-13 90 <0.01 0.000 <0.1 0.030 - <0.01 <0.01

Dieldrin (µg/L) 2006-13 90 <0.01 0.000 <0.01 0.012 - <0.01 <0.01

Endosulfan (µg/L) 2006-13 0 <0.01

Endosulfan-s (µg/L) 2006-13 90 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

Endosulfan-1 (µg/L) 2006-13 0 <0.01

Endosulfan-2 (µg/L) 2006-13 0 <0.01

Endrin (µg/L) 2006-13 90 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

Heptachlor (µg/L) 2006-13 90 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005 <0.005

HCB (µg/L) 2006-13 90 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

Heptachlor-epoxide (µg/L) 2006-13 90 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

Methoxychlor (µg/L) 2006-13 90 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

Parathion (µg/L) 2006-13 90 <0.1 0.000 <0.1 0.010 0.000 <0.1 <0.1

Total PCBs (µg/L) 2006-13 90 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1 <0.1

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BURWOOD BEACH WWTW


Summary of physicochemical, nutrients, metal/metalloid and organics data in Biosolids collected by Hunter Water during 2006 - 2013.


Error 75%ile 90%ile

Physicochemical

Total solids (%w/w) 2006-13 458 0.41 0.45 0.00 2.42 0.01 0.50 0.67

Volatile solids (%w/w) 2006-13 440 69.12 66.35 20.61 96.72 0.51 72.68 74.60

Ammonium N Total (mg/L N) 2006-13 440 24.00 25.03 0.01 85.40 0.55 30.13 39.00

Grease – total low range (mg/L) 2006-13 440 153.5 172.0 1.0 841.0 5.5 230.0 328.2

Fluoride (mg/L) 2006-13 3 0.77 0.67 0.42 0.82 0.13 0.80 0.81

Metals / Metalloids

Silver-Ag-AA Furnace (µg/L) 2006-13 152 22 23 4 63 1 29 40

Silver Ag-ICP (µg/L) 2006-13 279 11 12 0.5 38 0 15 18

Arsenic As-VGA (µg/L) 2006-13 431 14.7 18.33 2.6 130 0.70 19.75 30.5

Cadmium Cd-furnace (µg/L) 2006-13 152 4 5.93 0.5 128 1.04 6 8

Cadmium Cd-ICP (mg/L) 2006-13 279 0.005 0.01 0.005 0.06 0.00 0.01 0.01

Chromium Cr VI-furnace (µg/L) 2006-13 152 1 1.00 1 1 0.00 1 1

Chromium Cr VIi-furnace (µg/L) 2006-13 279 5 10 5 25 0.00 5 25

Chromium Cr-furnace (µg/L) 2006-13 152 46.5 68.16 1 750 7.41 68.5 105

Chromium Cr- ICP (µg/L) 2006-13 279 30 50 5 3200 10 40 70

Copper Cu-furnace (µg/L) 2006-13 152 839 954 125 3930 42.8 1134 1426

Copper Cu-ICP (µg/L) 2006-13 279 830 880 5 3300 20 1000 1300

Mercury Hg- VGA µg/L) 2006-13 431 3.7 3.93 0.005 10.2 0.08 4.8 6.3

Manganese Mn-furnace (µg/L) 2006-13 152 339 360 33 1270 13.73 446.25 512.5

Manganese -ICP (mg/L) 2006-13 279 0.39 0.41 0.06 1 0.01 0.47 0.57

Nickel Ni-furnace (µg/L) 2006-13 152 40 47.21 13 180 2.49 55 77.7

HUNTER WATER


BURWOOD BEACH WWTW



Error 75%ile 90%ile

Nickel Ni-ICP (mg/L) 2006-13 279 0.03 0.04 0.005 0.33 0.00 0.05 0.07

Lead Pb-furnace (µg/L) 2006-13 152 187 224 13 900 11.37 269.25 375

Lead Pb ICP µg/L) 2006-13 279 120 130 10 450 0.01 150 212

Selenium Se-VGA (µg/L)) 2006-13 431 0.1 0.91 0.05 5.9 0.06 1.7 2.7

Zinc Zn (mg/L) 2006-13 152 2.4 3.03 0.78 15.6 0.16 3.515 5.39

Zinc Zn-ICP (mg/L) 2006-13 279 2.2 2.46 0.13 6.9 0.06 2.8 3.7

Organics

Aldrin (µg/L) 2006-13 96 0 0 0 0 0 0 0

α-BHC Bhc-a (µg/L) 2006-13 96 0 0 0 0 0 0 0

β-BHC-b (µg/L) 2006-13 96 0 0 0 0 0 0 0

α Chlordane (µg/L) 2006-13 96 0 0 0 0 0 0 0

Chlordane (µg/L) 2006-13 96 0 0 0 0 0 0 0

λ Chlordane- (µg/L) 2006-13 13 0 0 0 0 0 0 0

Chlorpyrifos (µg/L) 2006-13 96 0 0.003 0 0.239 0.003 0 0

DDT (ug/L) 2006-13 96 0 0 0 0 0 0 0

DDD (µg/L) 2006-13 96 0 0 0 0 0 0 0

DDE (µg/L) 2006-13 96 0 0 0 0 0 0 0

Diazinon (µg/L) 2006-13 96 0 0 0 0 0 0 0

Dieldrin (µg/L) 2006-13 96 0 0.006 0 0.315 0.004 0 0

Endosulfan-s (µg/L) 2006-13 96 0 0 0 0 0 0 0

Endrin (µg/L) 2006-13 96 0 0 0 0 0 0 0

HCB (µg/L) 2006-13 96 0 0 0 0 0 0 0

Heptachlor-epoxide (µg/L) 2006-13 96 0 0.0001 0 0.013 0.0001 0 2.8

HUNTER WATER


BURWOOD BEACH WWTW



Error 75%ile 90%ile

Heptachlor (µg/L) 2006-13 96 0 0 0 0 0 0 0

Lindane (µg/L) 2006-13 96 0 0 0 0 0 0 0

Malathion (µg/L) 2006-13 96 0 0 0 0 0 0 0

Methoxychlor (µg/L) 2006-13 96 0 0 0 0 0 0 0

Parathion (µg/L) 2006-13 96 0 0 0 0 0 0 0

Total PCBs (µg/L) 2006-13 96 0 0 0 0 0 0 0

HUNTER WATER


BURWOOD BEACH WWTW


Appendix 2 – MRL 2007 Vector stick plots of

wind, current direction and temperature over

depth