Review of Environmental Factors Cronulla Wastewater Treatment Plant Odour Management Project
April 2011
© Sydney Water
Commercial-in-Confidence: This report and the information, ideas, concepts, methodologies, technologies and other material it contains remain the intellectual property of Sydney Water, unless otherwise agreed.
File Reference: S:\Sustainability\EP&M\WASTEWATER\Cronulla STP\Odour Project\30 Final REF\110321_DOC_Cronulla REF FINAL.doc Publication number SW239 3/11
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Declaration and sign-off
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Abbreviations
ADWF Average Dry Weather Flow ASS Acid Sulphate Soils CEMP Construction Environmental Management Plan CLM Contaminated Lands Management Act 1997 DECCW Department of Environment, Climate Change and Water (previously DECC) DOP Department of Planning DUAP Department of Urban Affairs and Planning (now DOP) DWLC Department of Water and Land Conservation EEC Endangered Ecological Community EIS Environmental Impact Statement EP&A Act Environmental Planning and Assessment Act 1979 EPBC Act Environment Protection and Biodiversity Conservation Act 1999 EPL Environment Protection Licence EP&M Environmental Planning and Management EPI Environmental Planning Instrument ESD Ecologically Sustainable Development GGBF Green and Golden Bell Frog GHFF Grey Headed Flying Fox ha Hectare FRP Fibre Reinforced Plastic IMS Integrated Management System JTA Jackson Teece Architects kV Kilovolts LEP Local Environment Plan LGA Local Government Area L/s Litres per second MCA Multi Criteria Analysis ML/d Megalitres per day m Metre mm Millimetre MWh MegaWatt hour NABERS National Australian Built Environment Rating System
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NGER Act National Greenhouse and Energy Reporting Act 2007 NPWS National Parks and Wildlife Service NSW New South Wales OEMP Operations Environmental Management Plan OTF Odour Treatment Facility OCU Odour Control Unit OU Odour Unit (measurement) PASS Potential Acid Sulphate Soils PHA Preliminary Hazard Analysis POEO Act Protection of the Environment Operations Act 1997 PST Primary Sedimentation Tanks Project The Cronulla Wastewater Treatment Plant Odour Management Project
REF Review of Environmental Factors RL Reduced level: height in metres above or below the Australian Height Datum RTA Roads and Traffic Authority SSC Sutherland Shire Council SEPP State Environmental Planning Policy STP Sewage Treatment Plant (renamed to Wastewater Treatment Plant) SWEMS Sydney Water Environmental Management System TSC Act Threatened Species Conservation Act 1995 UV Ultra violet VIA Visual Impact Assessment WARR Act Waste Avoidance and Resource Recovery Act 2001 WWWIMS Water and Wastewater Integrated Management System WWTP Cronulla Wastewater Treatment Plant
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Contents
Declaration and sign-off...... iii Executive summary ...... 11 1.Introduction...... 14 1.1 Background information ...... 14 1.2 Scope of the REF ...... 14 1.3 Stakeholder and community consultation ...... 15 1.3.1 Consultation objectives ...... 15 1.3.2 Consultation during project development ...... 15 1.3.3 Community consultation...... 15 1.3.4 Consultation before and during construction ...... 15 1.3.5 Consultation during operation ...... 16 1.4 Making a submission...... 16 2. Location and planning context...... 18 2.1 Location ...... 18 2.2 Environmental Planning and Assessment Act 1979 ...... 20 2.3 State Environmental Planning Policies (SEPP) ...... 20 2.3.1 SEPP (Kurnell Peninsula) 1989 and SEPP (Kurnell Peninsula) Amendment (Zoning) 2010 20 2.3.2 SEPP (Infrastructure) 2007...... 21 2.3.3 SEPP No. 14 – Coastal Wetlands...... 21 2.3.4 SEPP No. 19 – Bushland in Urban Areas...... 22 2.3.5 SEPP No 26 – Littoral Rainforests...... 22 2.3.6 SEPP No. 33 – Hazardous and Offensive Development...... 22 2.3.7 SEPP No. 71 – Coastal Protection ...... 22 2.4 Sutherland Shire Local Environment Plan (LEP) 2006 ...... 23 2.5 Other legislative considerations ...... 23 2.5.1 Coastal Protection Act 1979 ...... 23 2.5.2 Protection of the Environment Operations Act 1997 ...... 23 2.5.3 Heritage Act 1977 ...... 24 2.5.4 Waste Avoidance and Resource Recovery Act 2001 ...... 24 2.5.5 National Parks and Wildlife Act 1974 ...... 25 2.5.6 Contaminated Land Management Act 1997 ...... 25 2.5.7 Dangerous Goods Act 1975 ...... 25 2.5.8 Threatened Species Conservation Act 1995 ...... 26 2.6 Commonwealth legislation ...... 26
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2.6.1 Environment Protection and Biodiversity Conservation Act 1999 ...... 26 2.6.2 National Greenhouse Energy Reporting Act 2007 ...... 27 2.7 Local council approvals/liaison...... 27 3. Alternatives and justification for the project...... 28 3.1 Project need...... 28 3.2 Existing plant operations ...... 28 3.3 Alternatives and their assessment...... 31 3.4 Preferred option ...... 33 3.5 Ecologically Sustainable Development ...... 34 4. Description of the proposed work and activities ...... 39 4.1 Objectives of the project ...... 39 4.2 Scope of work...... 39 4.3 Proposed activities ...... 40 4.4 Materials and equipment...... 42 4.5 Work sites, access and vehicle movements ...... 43 4.6 Work times and timeframes ...... 43 4.7 Changes to the Project...... 44 5. Existing environment, potential impacts and measures...... 45 5.1 Topography, geology and soils...... 45 5.1.1 Existing environment...... 45 5.1.2 Impacts and environmental mitigation measures ...... 46 5.1.3 Conclusion ...... 47 5.2 Water and drainage...... 48 5.2.1 Existing environment...... 48 5.2.2 Impacts and environmental mitigation measures ...... 49 5.2.3 Conclusion ...... 50 5.3 Flora and fauna ...... 51 5.3.1 Existing environment...... 51 5.3.2 Impacts and environmental mitigation measures ...... 52 5.3.3 Conclusion ...... 53 5.4 Air quality...... 53 5.4.1 Existing environment...... 53 5.4.2 Impacts and environmental mitigation measures ...... 54 5.4.3 Conclusion ...... 55 5.5 Noise and vibration...... 55 5.5.1 Existing environment...... 55 5.5.2 Impacts and environmental measures...... 56 5.5.3 Conclusion ...... 56 5.6 Energy and chemical usage...... 57 5.6.1 Existing environment...... 57
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5.6.2 Impacts and environmental mitigation measures ...... 57 5.6.3 Conclusion ...... 59 5.7 Waste management ...... 59 5.7.1 Existing environment...... 59 5.7.2 Impacts and environmental measures...... 59 5.7.3 Conclusion ...... 60 5.8 Heritage – Aboriginal and non-Aboriginal...... 60 5.8.1 Existing environment...... 60 5.8.2 Impacts and environmental measures...... 61 5.8.3 Conclusion ...... 62 5.9 Traffic and access...... 62 5.9.1 Existing environment...... 62 5.9.2 Impacts and environmental measures...... 62 5.9.3 Conclusion ...... 63 5.10 Visual...... 63 5.10.1 Existing environment...... 63 5.10.2 Impacts and environmental measures...... 64 5.10.3 Conclusion ...... 69 5.11 Cumulative impact ...... 70 6. Environmental management...... 71 6.1 Project managers responsibilities ...... 71 6.2 Construction and environmental management ...... 71 6.3 Operational environmental management ...... 72 7. Conclusion ...... 73 8. References ...... 75 Appendices ...... 77 Appendix 1 Is an EIS required? ...... 78 Appendix 2 Heritage Impact Management...... 81 Appendix 3 Photos ...... 85 Appendix 4 Project Managers Responsibilities...... 87 Appendix 5 Visual Impact Assessment...... 88
List of Figures Figure 1: Cronulla WWTP site and surrounds...... 18 Figure 2: Cronulla WWTP site showing natural and operations areas ...... 19 Figure 3: Cronulla WWTP showing grit tank covers and access ...... 29 Figure 4: Cronulla WWTP infrastructure ...... 30 Figure 5: The Cronulla WWTP and adjacent areas ...... 45 Figure 6: The Cronulla WWTP, the proposed development area and Towra Point reserves...... 50
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Figure 7: Cronulla WWTP showing existing and post implementation odour impacts during normal operations and as identified by the Sydney Water CALPUFF model ...... 54 Figure 8: Diagrammatic 3D view of the proposed works ...... 65 Figure 9: Location of viewpoints selected by JTA for the assessment ...... 66 Figure 10: View from Captain Cook Drive with the proposed stack (View 5) ...... 68 Figure 11: View from the northern edge of Wanda Reserve (View 6) ...... 68 Figure 12: View from Bate Bay Road (View 4)...... 69
List of Tables Table 1: Options and their Assessment ...... 31 Table 2: MCA Summary...... 33 Table 3: Assessment of alternatives with respect to Ecologically Sustainable Development (ESD) ...... 36 Table 4: Project timeframe...... 43 Table 5: Licence (EPL no. 1728) chemical load limits and actual load measures at Cronulla WWTP...... 48 Table 6: Classification of visual impacts (JTA 2010)...... 65 Table 7: Summary of visual impacts (JTA, 2010) ...... 67
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Executive summary
Introduction
The Cronulla Wastewater Treatment Plant (WWTP) is located on the Kurnell Peninsula in the shire of Sutherland. The catchment covers an area of approximately 12,000 ha and extends from Kurnell in the east, to Sutherland in the west and to Helensburgh in the south. It services approximately 223,000 people.
The Project to upgrade and augment the existing odour treatment facility is aligned to the Sydney Water’s Corporate Plan of serving its customers. It will implement the Sydney Water Wastewater Treatment Plant Odour Management Strategy and will meet the Department of Environment, Climate Change and Water (DECCW) ‘no nuisance’ criteria.
This REF assesses the potential impacts of the Project on the WWTP site and on adjacent areas that include nature reserves, Ramsar wetlands and a newly released residential area adjacent to Wanda Reserve.
No significant environmental impact is anticipated as a result of the Project.
Description of the project
Sydney Water considered several options to reduce odour at the WWTP, using technical, social, environmental and financial criteria. The preferred option, later the Project, was selected based on its proven technology and good odour outcomes without significant environmental impacts. The comparatively simple design also resulted in relatively low capital and maintenance costs.
The Cronulla Odour Management Project includes:
• covering the odourous areas of the plant not covered at present
• extracting foul air from under the covers
• treating foul air in and odour treatment facility (OTF) comprising four biotrickling odour control units (OCU) and dispersing treated air via a stack
• refurbishing and corrosion protecting of the relevant existing infrastructure.
Objectives
The objectives of the Cronulla WWTP Project are to:
• significantly reduce the risk of odours impacting on the surrounding community
• achieve the DECCW ‘no nuisance’ odour criteria of two odour units (2 OU), 99% of the time during normal operation
• improve the reliability and extend the economic life of the existing infrastructure.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 Summary of environmental impacts
The proposed odour management work at the Cronulla WWTP has the potential to cause environmental impacts. This REF outlines the potential environmental impacts and the safeguards required for mitigation against such impacts. No significant environmental impact is expected as a result of the Project. However, Sydney Water would consider the need to vary the Environmental Protection Licence (EPL) No. 1728 to allow construction of the works and for the operation of the WWTP. These matters would be discussed with DECCW if/ when necessary.
The Cronulla WWTP land contains two distinct areas: the natural area, which has not generally been subject to development, and the fenced operations area, which contains the WWTP infrastructure and where the new development will be housed. The natural area of the site contains two endangered ecological communities (EEC): the Kurnell Dune Forest and the Littoral Rainforest. Neither is found within the operations area. However, mitigation measures, like spoil and drainage management will be in place to ensure there will be no significant impact to the EEC within the WWTP land.
It is expected that the proposed work will improve the general odour performance, and that air quality and odour impacts would improve as a result. During construction, dust and vehicle exhausts have the potential to impact air quality in the locality. However, due to the relatively short timeframe for construction (12 to 18 months) and through the implementation of mitigation measures outlined in this REF, the impact is not expected to be significant.
Excavation for construction of the proposed work would be managed to minimise soil erosion and sedimentation. Contaminated soils and acid sulphate soils are unlikely to be issues for the proposed work.
Site run-off will be collected and processed through the treatment system to ensure run-off does not impact significant ecological areas, like the Towra Point reserves which include Ramsar listed wetlands. Standard Sydney Water environmental management procedures will be used to ensure other potential impacts, like sedimentation, do not eventuate.
A small amount of vegetation removal would be required for the proposed work, however this would not result in a direct impact on any threatened species, populations or endangered ecological communities.
Six fauna species have been listed under the Threatened Species Conservation Act 1993. Two of the species are listed as ‘vulnerable’ under the Environmental Protection and Biodiversity Conservation Act 1999 (EPBC Act) (Commonwealth). None of these species is expected to be found within the operations area due to a lack of suitable habitat.
The proposed work would result in a temporary increase in construction related traffic. However, this increase will be restricted to the construction phase of the project and represents a short-term impact. Construction related traffic would be restricted to non-peak times where possible to ensure that impacts to local traffic conditions are not significant.
The addition of the OTF and discharge stack of 20 m will result in a visual impact from two vantage points, namely from Captain Cook Drive and Wanda Reserve, where the Project is expected to result in a moderate (Captain Cook Driver) and a low to moderate (Wanda Reserve) impact. The impact on the five other vantage points assessed is expected to range from negligible to low. However, the view from Bate Bay Road, while assessed as low, is important due to the potential concentration of observers within the proposed residential development area. The implementation of mitigation measures, eg painting colour and matt finishes, is expected to reduce the visual impact of the new infrastructure.
Biomass and nutrients will be used in the OCU biotrickling filters. No increase in operating chemicals is anticipated. Licensed storage capacity under the WorkCover Dangerous Goods Licence and EPL No. 1728 will be complied with.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 Potential impacts from construction include increased noise, however these impacts will be relatively short lived. Noise from the proposed plant operations will be minimised by the appropriate selection of fans and noise attenuated design. Noise levels are expected to comply with Australian standards and no significant impact is expected from either noise or vibration.
Environmental management
The initial concept design addressed Sydney Water’s environmental and social criteria to determine the preferred option, which resulted in the Project.
A detailed Construction Environmental Management Plan (CEMP) will manage environmental impacts during construction. It will be based on mitigation measures outlined in this REF.
Standard operating procedures at the WWTP will continue. Given the location and nature of the work, significant environmental impacts are not likely during operation, and standard procedures are considered sufficient to manage potential impacts. The WWTP will continue to comply with the EPL requirements.
Stakeholder and community consultation
A Communications Strategy has been prepared and is being implemented for the Project. Consultation with key stakeholders will continue throughout the design, construction and commissioning of the Project in accordance with the strategy. Key stakeholders and the community will be invited to comment on the REF when it is placed on public display at various locations for a period of two weeks. An information session will be organised to inform and engage the community about the Project. The Odour Management Alliance will be responsible for developing and implementing a Community Liaison Plan during the construction phase of the project.
Recommendation to proceed It is considered that all matters affecting or likely to affect the environment by reason of the proposed work, have been considered as required by section 111 of the Environmental Planning and Assessment Act 1979 (EP&A Act). Given the implementation of the measures outlined in this document, the proposed work will not have a significant adverse impact on the environment.
As the proposed work is not likely to significantly affect the environment, an Environmental Impact Statement (EIS) or further environmental assessment is not required. In addition, the Project will result in positive long-term impacts to the community, specifically improvements to the odour management of the WWTP .
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011
1.Introduction
1.1 Background information
Sydney Water’s Cronulla WWTP is located on Captain Cook Drive on the Kurnell Peninsula in the shire of Sutherland. The site is surrounded by native bushland, nature reserves and Ramsar wetlands. Industrial, recreational and residential uses are also located on the Peninsula.
The Cronulla WWTP, which has an average dry weather flow (ADWF) of 54 mega litres/day (ML/D), originally provided primary treatment of wastewater but by April 2001 the treatment level was upgraded to tertiary treatment. Treated effluent is discharged via a gravity pipeline to a point 5.2 km away at a shoreline outfall off Potter Point on Bate Bay. The outfall discharges approximately 6 m below the ocean surface.
The WWTP catchment extends from Kurnell in the east to Sutherland and Heathcote in the west and Helensburgh in the south. The WWTP services an equivalent population of 223,000. The catchment covers an area of approximately 12,000 ha and is composed of residential, industrial and commercial development.
The WWTP includes a small odour management facility installed in 2001. It does not adequately addresses fugitive, or escaping, odours. Consequently the WWTP was nominated in the Sydney Water Odour Management Strategy as a high risk WWTP to ensure Sydney Water meets its customer service commitments.
Further odour management works are necessary to meet DECCW’s ‘no nuisance’ criteria. Sydney Water aims to meet these criteria and ensure that odour emissions do not exceed two odour units (2 OU) for 99% of the modelled time of one second for a nose response at the nearest sensitive receptor during normal operations. The nearest sensitive receptor is located on the rezoned development area adjacent the WWTP and the model used is the Sydney Water CALPUFF model.
The Cronulla Odour Management Project includes:
• covering the odourous areas of the plant not covered at present
• extracting foul air from under the covers
• treating foul air in an OTF comprising four biotrickling OCU and dispersing treated air via a stack
• refurbishing and corrosion protecting of the relevant existing infrastructure. This REF documents the outcomes of the environmental assessment and identifies safeguards to be implemented to ensure there is no significant environmental impact as a result of the Project.
1.2 Scope of the REF Sydney Water is a statutory state-owned corporation and as such, is classified as a public authority under section 4 of the Environmental Planning and Assessment Act 1979 (EP&A Act) and as a determining authority under Part 5 of this Act. Under section 111 of the EP&A Act and regulation 228 of the EP&A Regulation, Sydney Water is responsible for assessing the impacts of its activities.
This REF is an assessment of the potential environmental impacts associated with the Odour Management Project . The purpose of this REF is to identify the significance of any adverse
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 environmental impacts that could arise from the work and to determine whether or not there is a need for an environmental impact statement (or equivalent). The REF identifies measures to avoid or minimise potential environmental impacts that may be associated with the Project.
1.3 Stakeholder and community consultation 1.3.1 Consultation objectives
Sydney Water has prepared a Communications Strategy for the Odour Management Project. The strategy ensures that the community and key stakeholders are provided with clear, accurate and timely information throughout all stages of the work, and have an opportunity to provide input as part of the environmental assessment process. 1.3.2 Consultation during project development
Since 1997, Sydney Water has consulted with key stakeholders regarding odour management, including: the Minister’s office, Sutherland Shire Council (SCC), Department of Planning (DOP), DECCW and the land holder and developer adjacent the plant, Australand.
As part of this engagement initiative, Sydney Water has carried out regular updates, meetings and workshops, informing stakeholders and obtaining their feedback in relation to the Project for managing odour at the WWTP.
In order to reduce the current odour plume on adjacent lands, Sydney Water conducted an investigation to identify the primary odour sources from the plant and assessed a number of odour management options, which have been summarised in Table 1: Options and their Assessment. 1.3.3 Community consultation
As part of the Communications Strategy for the Cronulla WWTP Odour Management Project, Sydney Water will undertake broader consultation with the local community and key stakeholders to obtain information that could help mitigate potential environmental and social impacts from the Project.
The REF will be placed on public display at various locations within the SSC area for a period of two weeks. The community and stakeholders will be invited to comment by direct mail-outs and advertising in the local paper. At the end of the public display period, and once all submissions have been received, a Decisions Report addressing all issues raised will be produced by Sydney Water. The Project may be refined in the event that a submission identifies any issue of project significance.
The community and stakeholders will be invited to an information session about the Project. This will give the community an opportunity to discuss the Project with Sydney Water staff. The information session will be held at Cronulla Central Community Hall, Cronulla on Saturday 9 April 2011. 1.3.4 Consultation before and during construction
Sydney Water will deliver relevant information to the community and stakeholders and will manage issues during the planning stage of the project. This will be in line with the Communications Strategy for the project.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 Letters will be sent to the local community and key stakeholders to notify them of the proposed Odour Management Project, inform them about the REF display and invite them to an information session.
Copies of the REF will be sent to local community groups, key stakeholders and display locations.
A fact sheet will be distributed at the display venues and at the information session. It will include details of the objectives and outcomes of the project and potential issues and their management. It will include images from the Visual Impact Assessment report. The fact sheet and contact details will also be available on the Sydney Water website.
During the construction phase of the project, the Odour Management Alliance will be required to work with Sydney Water to develop and implement a Community Liaison Plan in line with Sydney Water’s Communications Strategy for the Project. The Alliance will be required to keep the community informed throughout the construction phase of the proposed work and to manage issues and complaints, if they arise.
Complaints management during construction will be in accordance with the existing Sydney Water Customer Complaint Policy and Procedure . 1.3.5 Consultation during operation
Following commissioning of the proposed work, Sydney Water standard policies and procedures for customer and community relations will apply.
1.4 Making a submission
The REF will be displayed for a period of two weeks from Monday 4 April 2011 to Monday 18 April 2011 at the following locations:
• Sutherland Shire Council
• Cronulla Library
• Caringbah Library.
Written submissions from public authorities, interested groups, organisations and the community are invited and should be addressed to the contact below by Monday 18 April 2011:
Peta G. Lilburne
Senior Environmental Scientist, Cronulla WWTP Odour Management Project
Sydney Water
PO Box 399
Parramatta NSW 2124
Submissions must be made in writing and may comment on any aspect of the Project or REF.
All information in written representations is collected for the sole purpose of assisting in the assessment of the Project. The information may be used by Sydney Water during the environmental impact assessment and the Decisions Report processes and may be disclosed to appropriate agencies such as DECCW or the DOP. Where the respondent indicates at the time of submittal that the information shall remain confidential, Sydney Water will attempt to ensure that it
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 remains so but there may be legislative or legal justification for its release, for example under the Freedom of Information Act 1989 . The supply of information is voluntary.
Each respondent has free access at all times to the information supplied by that respondent but not to any material supplied by others if a respondent has indicated that their representation should remain confidential. Any respondent may make a correction to any information they have provided by making the correction in writing and sending it to the same address where the original documentation was sent.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011
2. Location and planning context
2.1 Location The Cronulla WWTP is located on Captain Cook Drive on the Kurnell Peninsula within the Sutherland LGA. The site is situated on Botany Bay and has views to Bate Bay in the Tasman Sea. Refer to Figure 1.
Figure 1: Cronulla WWTP site and surrounds This REF makes a distinction between two parts of the WWTP site: the larger, natural area and the smaller operations area (Figure 2). The natural area contains two EEC and the GGBF and possibly other threatened or endangered species. The operations area has been significantly developed and contains hardstand areas, buildings and other infrastructure related to wastewater treatment. Vegetation within the operations area is limited and has generally been the result of a revegetation program.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011
Figure 2: Cronulla WWTP site showing natural and operations areas
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 2.2 Environmental Planning and Assessment Act 1979
This Project is being assessed in accordance with the EP&A Act and the associated EP&A Regulation 2000. The Act institutes a system for environmental planning and assessment and development approvals. The EP&A Act also establishes environmental planning instruments, including State Environmental Planning Policies (SEPP) and Local Environmental Plans (LEP).
The proposed work does not require development consent under Part 4 of the EP&A Act, and is not a project under Part 3A. Hence, the proposed upgrade work at Cronulla WWTP will be undertaken as an activity under Part 5 of the EP&A Act. A project can be assessed under Part 5 of the Act if it: • may be carried out without development consent • is not a prohibited development • is carried out, or approved, by a determining authority.
A determining authority is defined in Part 5 section 110 of the Act: ‘a Minister or public authority and, in relation to any activity, the Minister or public authority by or on whose behalf the activity is or is to be carried out or any Minister or public authority whose approval is required in order to enable the activity to be carried out .’
Sydney Water will carry out the Project as a Statutory State Owned Corporation, and Sydney Water will be the determining authority under Part 5 of the EP&A Act.
Under section 111 of the EP&A Act and in accordance with the Department of Urban Affairs and Planning (DUAP) guideline ‘Is an EIS required?’ Sydney Water is responsible for assessing the impacts of its activities, and determining whether an EIS is required. The DUAP guideline ‘Is an EIS required?’ identifies factors to be addressed in the environmental impact assessment process.
Under Part 5 of the EP&A Act, Sydney Water will examine and consider the effects of the project on the environment, the conclusions of the REF and any submissions received following the public display of the document. A Decisions Report will document the results of this examination and recommend any refinement to the project necessary to address matters raised in the submissions. Sydney Water will write to all stakeholders that make a submission, outlining how their issues have been addressed.
2.3 State Environmental Planning Policies (SEPP) 2.3.1 SEPP (Kurnell Peninsula) 1989 and SEPP (Kurnell Peninsula) Amendment (Zoning) 2010
The WWTP site is zoned 5(a) Special Uses under SEPP (Kurnell Peninsula) 1989. The objectives of this zone are to:
• identify land which is currently used by a public utility undertaking, servicing the needs of the community and industry with certain facilities and services
• maintain and provide for the economic and efficient provision of services and appropriate infrastructure
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 • provide for the continued use of the land for the purpose indicated by red lettering on the [Zoning] map.
Utility development is a permissible use for the purposes of utility installations and utility undertakings.
SEPP (Kurnell Peninsula) 1989 states in section 14, that development must not significantly affect or alter the topographical or ecological features of the land. No significant impacts will result from the Project. Refer to section 5.1 Topography, geology and soils and 5.3 Flora and fauna.
SEPP (Kurnell Peninsula) Amendment (Zoning) 2010 applies to land adjacent to the WWTP. It rezones this land for the purposes of recreational and residential use. 2.3.2 SEPP (Infrastructure) 2007
The aim of SEPP (Infrastructure) 2007 is to facilitate the effective delivery of infrastructure across the State.
Section 106 (1) relates to the Project and states:
Development for the purpose of sewage treatment plants or bio-solids treatment facilities may be carried out:
(a) by or on behalf of a public authority or any person licensed under the Water Industry Competition Act 2006, without consent on land in a prescribed zone, and (b) by any other person with consent in a prescribed zone.
‘Sewage treatment plant’ means a facility for the treatment and disposal of sewage, whether or not the facility supplies recycled water for use as an alternative water supply.
‘Bio-solids treatment facility’ means a facility for the treatment of bio-solids from a sewage treatment plant or from a water recycling facility.
‘Prescribed zone’ means any of the following land use zones or a land use zone that is equivalent to any of those zones:
(f) SP2 Infrastructure
SEPP (Infrastructure) permits infrastructure development without council consent in zones where it is currently permissible with consent, as the WWTP site is in SEPP (Kurnell Peninsula) 1989.
Consequently, in accordance with SEPP (Infrastructure) and, given that Sydney Water is a determining authority under Part 5 of the EP&A Act, Sydney Water may carry out the Project without SSC consent. 2.3.3 SEPP No. 14 – Coastal Wetlands
SEPP No. 14 – Coastal Wetlands aims to ensure that coastal wetlands are conserved in the environmental and economic interests of the State. The objectives include:
• protecting valuable wetlands
• ensuring that a wide range of benefits of wetlands continue
• enabling cumulative effects of existing and proposed developments to be assessed
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 • encouraging developers to find alternatives to disturbing wetlands.
This SEPP provides guidance for consent authorities in terms of issues to consider when determining whether there is potential for a listed wetland to be affected by a project. Towra Point Aquatic Reserve is a listed wetland located to the North of the WWTP. However, the wetland will not be affected by the Project. Refer to sections 5.1 Topography, geology and soils, and 5.2 Water and drainage and 5.3 Flora and fauna. 2.3.4 SEPP No. 19 – Bushland in Urban Areas
The aim of this policy is to protect and preserve bushland within urban areas for its aesthetic, recreational, educational and scientific resource values. There are no lands classified as ‘ Urban Bushland ’ on or nearby the WWTP site as described in Schedule 1 of the SEPP. 2.3.5 SEPP No 26 – Littoral Rainforests
SEPP No. 26 aims to ensure that Littoral Rainforest areas are protected from potential damage or destruction, and preserved in their natural state. The policy applies to 'core' areas of Littoral Rainforest as well as a 100 m wide buffer area surrounding these core areas, except for residential land and areas to which SEPP No. 14 - Coastal Wetlands applies.
There is a stand of Littoral Rainforest on the northern boundary of operations area of the WWTP site. However the proposed works will be confined to the sealed areas and is unlikely to impact the remnant stand of Littoral Rainforest on site. Refer to 5.3 Flora and fauna. 2.3.6 SEPP No. 33 – Hazardous and Offensive Development
The SEPP No. 33 applies to development that is hazardous or potentially hazardous, or offensive or potentially offensive industry, as defined in the SEPP. The SEPP potentially requires the preparation of a preliminary hazard analysis (PHA) especially if the project is for an industrial development for approval under Part 3A or Part 4 of the EP&A Act. As the Project is being assessed under Part 5 of the EP&A Act, a PHA is not required.
The DOP’s Applying SEPP 33 (Consultation Draft) (DOP 2008) provides criteria against which potential industrial development must be assessed to determine if the work is potentially hazardous or potentially offensive. The criteria specify threshold limits on the quantities of hazardous material to be stored and the level of transportation of these materials to determine whether a PHA is required. The chemical use required by the Project falls below this threshold, however, the increase will be managed in accordance with the existing legislation, regulation and policies. Refer to 5.6 Energy and chemical usage. 2.3.7 SEPP No. 71 – Coastal Protection
SEPP No. 71 aims to ensure that:
• development in the NSW coastal zone is appropriate and suitably located
• there is a consistent and strategic approach to coastal planning and management
• there is a clear development assessment framework for the coastal zone.
SEPP No. 71 also requires that all significant coastal development on land within the Coastal Zone be automatically referred to the Minister to ensure that all development is in accordance with the principles and objectives of the NSW Government’s Coastal Policy (1997). The WWTP site is within a designated coastal zone. However, the WWTP is not considered a ‘sensitive coastal
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 location’ under the Act. The proposed work is not considered significant development, as described under the SEPP, therefore a referral to the Minister is not required.
2.4 Sutherland Shire Local Environment Plan (LEP) 2006
Cronulla WWTP is located within SSC area. Section 4 of the Sutherland Shire LEP (2006) states that the LEP applies to all land within Sutherland Shire, except to land to which the Sydney Regional Environmental Plan No. 17, now deemed SEPP (Kurnell Peninsula) 1989, applies. Therefore, the Sutherland Shire LEP 2006 does not apply to Cronulla WWTP or this Project. Under SEPP (Kurnell Peninsula) 1989, the land is zoned 5(a) Special Uses, for infrastructure purposes and which is a permissible use. Land use zone 5(a) is the equivalent of zone SP2 Infrastructure under the new zoning provisions. SEPP (Infrastructure) 2007 allows Sydney Water to undertake the proposed work under Part 5 of the EP&A Act, providing the development is not a prohibited land use and provided there are no significant environmental impacts as a result of the development. The Project meets both criteria.
2.5 Other legislative considerations 2.5.1 Coastal Protection Act 1979
The Coastal Protection Act 1979 aims to protect the coastal environment of NSW for the benefit of both present and future generations. Under the Act, concurrence from the Minister is required to carry out certain development within the Coastal Zone. This is to ensure that proposed developments are designed appropriately, to minimise adverse environmental impacts and to uphold the NSW Coastal Policy (1997).
The Sydney Water planning and impact management process for this Project is consistent with the requirements of this Act and the DOP 2006, Protecting our Coast The Comprehensive Coastal Assessment Tool Kit, NSW Government, Sydney.
The WWTP is located within the designated Coastal Zone but the Project is confined to the WWTP operations area. No impact to the marine environment, marine waters or beaches is anticipated. However the implementation of mitigation measures in the REF will minimise any impacts. The Project is consistent with the principles of ecologically sustainable development (ESD). As such, concurrence from the Minister under the Coastal Protection Act 1979 is not required. 2.5.2 Protection of the Environment Operations Act 1997
The Protection of Environment Operation Act 1997 (POEO Act) is in place to protect the public and the environment from potential harm. It includes the concept of ‘offensive odour’ and it is an offence for scheduled activities to emit ‘offensive odour’. The POEO Act also provides a defence against prosecution if an activity is complying with any conditions of its environment protection licence that are aimed at preventing or minimising the emission of ‘offensive odour’ from a particular source. Section 129 of the POEO Act states:
‘The occupier of any premises at which scheduled activities are carried out under the authority conferred by the licence must not cause or permit the emission of any offensive odour from the premises to which the licence applies.’
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 The operation of Cronulla WWTP and discharges are licensed by DECCW (EPL No. 1728) under the POEO Act. Under the EPL, Sydney Water’s obligations include complying with the EPL, controlling pollution of water and air, and reporting incidents. Sydney Water reports on incidents at the Cronulla WWTP as a part of its Annual Returns.
The Project will improve odour concentrations released from the WWTP and will reduce the risk of odour impacting on the surrounding areas. Furthermore, the Project will comply with one of the objectives of the EPL in relation to continuing improvement in environmental performance.
Sydney Water would consider the need to vary the licence to allow construction of the works and for the operation of the WWTP . These matters would be discussed with DECCW if/when necessary. 2.5.3 Heritage Act 1977
The Heritage Act 1977 was introduced to conserve the environmental heritage of NSW. Under this Act, environmental heritage is defined as including buildings, works, relics or places which are of historic, scientific, cultural, social, archaeological, architectural, natural or aesthetic significance to the state.
The Act provides for the making of a variety of orders and permits to protect items of environmental heritage, including items classified as ‘relics’. A relic is defined under the Heritage Act as follows:
‘…any deposit, object or material evidence which –
a) relates to settlement of the area that comprises New South Wales, not being Aboriginal Settlement; and
b) is more than 50 years old.’
Section 139 of the Heritage Act 1977 states the following:
‘…A person shall not disturb or excavate any land for the purpose of discovering, exposing or moving a relic, not being a relic subject to a conservation instrument, except in accordance with an excavation permit.’
The impact of the proposed works on heritage items and values is detailed in section 5.8 Heritage of this REF. It determines that no excavation permits under the Heritage Act are required at this time. 2.5.4 Waste Avoidance and Resource Recovery Act 2001
The Waste Avoidance and Resource Recovery Act 2001 (WARR Act) aims to:
‘ensure that resource management options are considered against a hierarchy of the following order:
i. avoidance of unnecessary resource consumption;
ii. resource recovery (including reuse, reprocessing, recycling and energy recovery);
iii. disposal.’
It also aims to:
‘minimise the consumption of natural resources and final disposal of waste by encouraging the avoidance of waste and the reuse and recycling of waste.’
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 The Project is consistent with aims of the WARR Act because it involves refurbishing corroded concrete sections of the inlet channels and scum removal areas rather than replacing them. The REF has identified mitigation measures to avoid, reduce and manage waste that will be incorporated into the Construction Environmental Management Plan (CEMP), including recycling where possible. Waste generated by operations will be managed in accordance with the WARR Act. Refer to section 5.7 Waste management. 2.5.5 National Parks and Wildlife Act 1974
The National Parks and Wildlife Act 1974 (NPW Act) is administered by the NSW National Parks and Wildlife Services (NPWS) through DECCW. Under the provisions of the NPW Act, the excavation or destruction of archaeological sites, relics or remains may only be undertaken with a permit obtained from the Director-General of the NPWS.
Places, sites and objects of archaeological and Aboriginal cultural significance are protected under the National Parks and Wildlife Act 1974 (NPW Act). It is an offence to damage or destroy them without prior permission from the Director General of DECCW.
No activity is likely to result in disturbance to Aboriginal heritage. The need for an Aboriginal heritage impact permit under section 90 of the NPW Act is not anticipated. Refer to section 5.8 Heritage – Aboriginal and non-Aboriginal. 2.5.6 Contaminated Land Management Act 1997
This Contaminated Land Management Act 1997 (CLM Act) promotes better management of contaminated land and includes establishing:
‘a process for reporting, investigating and (where appropriate) remediating land areas where contamination presents a significant risk of harm to human health or some other aspect of the environment ’ (section 3)
A particular objective set out in section 3 (2) (d), is ‘ to ensure that contaminated land is managed with regard to the principles of ecologically sustainable development.’
When dealing with a potentially contaminating activity or within contaminated lands, it is necessary to comply with the requirements of the CLM Act. However, the Project is not considered likely to generate a contaminating activity or to disturb contaminated land. Sydney Water is not aware of site contamination issues. Refer to section 5.1 Topography, geology and soils of this REF for more information. 2.5.7 Dangerous Goods Act 1975
Dangerous goods in any quantity must be stored safely and in compliance with the requirements of the Dangerous Goods Act 1975 (DG Act). Depending on their class, dangerous goods above certain quantities must be licensed. A range of substances required to operate the WWTP are classified as dangerous goods. During the proposed construction activities and WWTP operation, all chemical use, storage and transportation must meet the requirements of the Act and the relevant approvals.
The WWTP has a licence under the DG Act, which can be amended to reflect changes in the type and quantities of dangerous good stored and used on site as a result of the proposed work. However, no change to the licence is anticipated. Dangerous goods are discussed further in section 5.6 Energy and chemical usage of this REF.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 2.5.8 Threatened Species Conservation Act 1995
The Threatened Species Conservation Act 1995 (TSC Act) establishes a framework for the protection of threatened species, populations and ecological communities in New South Wales (NSW). Schedules 1 and 2 of the TSC Act list terrestrial species, populations and ecological communities considered threatened in NSW. Under the TSC Act, if a significant impact is determined, a Species Impact Statement (SIS) and licence are required.
The impact of the project on threatened species, communities and their habitats is described in section 5.3 Flora and fauna of this REF. The proposed work is unlikely to affect any threatened species. As such neither a Species Impact Statement nor approvals will be required under the TSC Act.
2.6 Commonwealth legislation 2.6.1 Environment Protection and Biodiversity Conservation Act 1999
Under the Commonwealth Environmental Protection and Biodiversity Conservation Act 1999 (EPBC Act), activities that are likely to have a significant impact on matters of national environmental significance (NES), actions undertaken on Commonwealth lands, or by the Commonwealth are subject to assessment and approval. Matters of NES are identified in the EPBC Act as:
• World Heritage properties
• National Heritage places
• Ramsar wetlands
• Nationally threatened species and communities
• Migratory species protected under international agreements
• Commonwealth marine environment
• Great Barrier Reef Marine Park
• Nuclear actions.
There are no world heritage properties or national heritage places in the vicinity of the proposed work and work will not be undertaken on Commonwealth land. Accordingly, the project will not have a significant impact on these matters.
No nuclear actions will be undertaken as part of the work.
The Project is, however, located in the vicinity of a Ramsar wetland and impacts on the wetlands or on nationally threatened species and communities are discussed in section 5.3 Flora and fauna of this REF. Overall, a small amount of vegetation removal would be required to implement the Project. It would not result in a direct impact on any threatened species, populations or endangered ecological communities nor on the Ramsar wetland.
Accordingly, it is considered that referral of the project to the Department of Environment and Heritage under the EPBC Act will not be required.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 2.6.2 National Greenhouse Energy Reporting Act 2007
The National Greenhouse Energy Reporting Act 2007 (NGER Act) requires that Sydney Water report on greenhouse gas emissions, energy production and consumption from its facilities. Detailed reporting extends to contractors and subcontractors undertaking work for Sydney Water will be specified in the CEMP. Refer to section 5.6 Energy and chemical usage.
2.7 Local council approvals/liaison
It is Sydney Water’s policy that local councils are provided with reasonable notice of an intention to carry out a development, regardless of the need for Development Consent. Given that proposed work will be carried out within the Sutherland LGA and council is a manager of land adjacent to the WWTP site (eg Charlotte Breen Reserve), council will be notified of the Odour Management Project at the Cronulla WWTP.
Council will be provided with a copy of the REF for comment during the public exhibition period. Where applicable, works will abide by accepted guidelines, restrictions or approval requirements identified by the council. Council will also be notified regarding specific impacts associated with work such as traffic management.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 3. Alternatives and justification for the project
3.1 Project need
The Sydney Water WWTP Odour Management Strategy (2008) took a risk-based approach to addressing nuisance odour emitted from treatment plants near existing or future residential development. The Strategy aims to significantly improve odour mitigation at high risk WWTPs within five years. Given the extent of current odour levels and the recent rezoning of lands adjacent the WWTP from industrial to residential uses, the Cronulla WWTP was identified as a ‘high risk’ treatment plant.
Section 129 of the POEO Act states that the occupier of any premises at which scheduled activities are carried out under a ‘ licence must not permit the emission of any offensive odour from the premises to which the licence applies’. The WWTP is a licensed premise (EPL No. 1728). Consequently Sydney Water has a legal obligation to reduce the odour emissions from the Cronulla WWTP.
The uncovered portions of the PST at the WWTP were identified as a major source of untreated odours, accounting for approximately 50% of the total odour emissions on the site.
The existing OTF treats odours from covered primary process units, namely the inlet works, screening grit removal tanks and the effluent launders. The OTF is adequately sized to treat the airflow it is receiving from these covered units. However, the ventilation rates within these units from which foul air is drawn are sub-optimal resulting in fugitive emissions because the covered units are not sealed sufficiently. Poor ventilation is also causing corrosion under the covers of both concrete and steel supporting frames.
Further odour management is necessary to meet DECCW’s ‘no nuisance’ criteria.
3.2 Existing plant operations
The WWTP has a catchment area of approximately 12,000 ha and the current population served by the WWTP is approximately 223,000. A small population increase is expected over the next 20 years.
The average dry weather flow (ADWF) is 54 megalitre a day (ML/d). The plant has a design capacity of 56.7 ML/d ADWF and is sufficient to meet the population increase. The Cronulla WWTP is a long-term asset and warrants prudent investment to remain fully functional.
Wastewater treatment
Management of wastewater is identified below.
• wastewater is pumped via two pumping stations (SPS 362 and SPS 676) to the existing inlet structure
• wastewater is screened to remove items such as rags, plastic, timber etc. Grit is also captured in a grit removal facility.
• wastewater then passes into the primary sedimentation tanks from where it goes one of four ways.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 − Raw sludge and scum captured in the PST are sent to the gravity thickener then to the feed tank and the digester, then to the centrifuge for dewatering and biosolids reuse.
− Settled wastewater is pumped to the bioreactors where biochemical oxygen demand is removed and nitrification and de-nitrification occurs. Mixed liquor from the bioreactors flows to the clarifiers and then to tertiary filters. The filtered effluent is disinfected with ultraviolet light (UV) and is discharged to the ocean via the outfall at Potter Point.
− The waste activated sludge (WAS) from the bioreactors is thickened in dissolved air floatation tanks and the thickened WAS is digested in the anaerobic digesters along with raw sludge and scum using centrifuges. Dewatered sludge is out loaded and used for beneficial applications.
− A portion of the treated wastewater from the tertiary filters is given a sodium hypochlorite dosing, and UV treatment to provide reclaimed effluent in the treatment plant.
• Ii times of wet weather, if necessary, wastewater can be diverted into the storage lagoon for later treatment or for discharge.
Figure 3: Cronulla WWTP showing grit tank covers and access
Existing biosolids treatment
The existing biosolids treatment process consists of:
• anaerobic digestion of sludge
• dewatering in centrifuges to consolidate biosolids
• transport of biosolids to the handling building prior to out loading into trucks for transport to offsite uses.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 Methane gas, produced in the digesters, is sent to the co-generation plant to generate electricity for on-site uses.
Figure 4: Cronulla WWTP infrastructure
Existing odour management
The odour control systems for the existing plant rely on either the capture/ treatment of foul air from odorous treatment units, or on ventilation and dispersion. There are two capture/ treatment systems in place.
The odour capture/ treatment system No. 1 comprises:
• extraction of foul air from the covered inlet works including distribution channel, inlet screens and grit tanks, the primary sedimentation effluent launders and channel, the fine screens and inter-stage pumping station wet wells and the gravity thickener
• ventilation of the headspace above these units using a rate of 6 air changes per hour
• humidification of foul air
• treatment of foul air in a four cell compost bed biofilter (192 m2).
The capture/Treatment System No. 2 comprises:
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 • extraction of foul air from the dewatering centrifuges and the covered centrate well
• humidification of extracted air prior to treatment in a three cell compost bed biofilter (45 m2) located close to the dewatered biosolids handling and storage building.
The other significant odorous source is the dewatered biosolids handling and storage building. It has a forced ventilation rate of 6 air changes per hour by vertical discharge roof fans for dispersion of foul air.
3.3 Alternatives and their assessment
Sydney Water assessed a number of odour management options, which were evaluated for:
• process performance
• feasibility of installation
• enclosure size
• capital and operating costs. All options were aimed at meeting the DECCW ‘no nuisance’ criteria and the WWTP Odour Management Strategy, and at compliance with the relevant legislation and the EPL.
Table 1: Options and their Assessment
Option Description
Base case Do nothing - This is not acceptable, as the existing odour treatment facility cannot reduce the odour nuisance from the plant and it is operating at full capacity now. Option 1 : Installation of covers on the Foul air extracted from under the covers will be treated in a biotrickling PST and enclosing the PST inlet system, with foul air from inside the building discharged up a stack or channel in a building + foul air used for dilution of the treated air. This option will have: treatment in a biotrickling filter system • easy access to equipment in PST inlet • higher odour risk due building venting to atmosphere • higher visual impact • less access to PST main body (can be alleviated by providing coves with sufficient access hatches) • building potentially hazardous • higher capital costs. This option was short listed initially, but later culled during a MultiCriteria Assessment (MCA) workshop, due to the disadvantages listed above . Option 2 : Installation of covers on the Foul air extracted from under the covers and box will be treated in a PST and enclosure of PST inlet biotrickling filter. This option will have: channel in a low profile box + foul air • low odour risk due to a larger air flow requiring treatment treatment in a biotrickling filter system • complex design • higher capital costs. This option was short listed initially, but later culled during an MCA workshop, in preference to option 3, which is similar but simpler . Option 3 : Installation of covers over Foul air from under the covers will be treated in a biotrickling filter the entire PST (inclusive of the inlet system. Installation of a water spray system was considered to minimise channel) + foul air treatment in a equipment access requirements under the covers. Based on experience biotrickling filter system from Warriewood WWTP, it was decided that providing adequate access
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 hatches is a cost effective alternative with a relatively lower capital cost. This option will have: • low odour risk • lowest cost for covering • simple design • proven technology, as experienced at Brooklyn and Warriewood WWTPs • relatively low visual impact • less access to PST ( to be alleviated by access hatches). Without a new scum system the capital cost has reduced. This option was one of the 2 selected for further consideration and ultimately became the preferred option. Option 4 . Enclosure of the entire Discharge untreated air up a stack. This option will have: PST in a building, discharge air • highest capital cost though a stack without treatment • highest airflow requirement • significant visual impact • odour risk is assessed as low if discharged at sufficient height • air will require treatment if odour complaints arise. This option was not considered further. Option 5 : Chemical Dosing at inlet Chemical dosing to minimise odours from the PSTs and alleviate the need works for covers. This option will have: • no PST coverings • low capital cost • full access to PSTs maintained • uses a single bio trickling filter to treat the air extracted from existing covered areas • additional gravity sludge thickening unit is required to reduce PST sludge inventory. Issues • later technical advice from operations confirmed that this option is not reliable and cannot guarantee the odour removal performance • requires a trial to verify performance before installing full scale plant and so cannot meet the timeframe requirement for project completion • potential for shortage of chemicals and high cost increases • high operating cost. This option was one of the two options selected for further consideration but was not judged the preferred option.
Large enclosures capture and treat more air resulting in higher operating costs than small areas. Consequently, two options, options 3 and 5, were selected for further investigation because they had the smallest enclosed area.
Option 3 has relatively low capital and maintenance costs due to a simple design and a relatively small volume of infrastructure enclosure. The option is based on proven technology. Option 5 is the only option without covers. Hence options 3 and 5 were short listed for further consideration.
A multi-criteria assessment (MCA) was undertaken to determine the preferred option when both cost and non-cost criteria were taken into consideration.
The MCA used four main categories: technical, social, environmental and economic to identify the preferred option. Sub-criteria were also considered for each criterion in the evaluation.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 Summary of the final score for MCA is as per the table below.
Table 2: MCA Summary
Category Weighting Normalised Score
Option 3- low level Option 5- Chemical covers and biotrickling dosing filter
Technical 30 3.7 3.1 Social 30 5.0 2.4 Environmental 10 1.8 3.0 Financial 30 4.91 4.6 Total 100 4.26 3.33
Although the capital costs for option 5 were lower than option 3, the operating cost was much higher. Further technical information confirmed that option 5 was not reliable and could not guarantee the necessary odour performance. Option 3 received a relatively low environmental score due to the amount of covering material required. However, option 3 is reliable and has a proven track record with Sydney Water and other users of the biotrickling filter system.
The MCA evaluated option 3 as the preferred option for controlling odours at the WWTP.
The details of the assessment are specified in a technical memorandum titled ‘ Cronulla Odour Abatement Options assessment using Multi Criteria Analysis’, 1 May 2009.
3.4 Preferred option
Odour modelling indicates that covering key odourous areas and treating the air in an OCF with four OCU with biotrickling filters and a stack would meet the aim and objectives of the Project.
The objectives of the Cronulla WWTP Project are to:
• significantly reduce the risk of odours impacting on the surrounding community
• achieve the DECCW ‘no nuisance’ odour criteria of 2 OU, 99% of the time during plant operation
• improve the reliability and extend the economic life of the existing infrastructure.
CALPUFF modelling indicates that option 3 outcomes would meet the DECCW ‘no nuisance’ criteria of no more than 2 OU, 99% of the time of a one second nose response at the nearest sensitive reception located on rezoned land at Wanda Reserve adjacent the WWTP. Refer to Figure 7 for the CALPUFF model of ‘before and after’ odour impacts.
The Project would comply with relevant legislation and the EPL’s continuing improvement objective. It is one of a number of projects that are implementing the Sydney Water WWTP Odour Management Strategy.
The cover system over the PST will consist of approximately 10 m sections of structurally supported retractable fabric covers that can be rolled back easily when full access to the tanks is required. Inspection hatches will be provided in the fixed walkway areas in between the sections of the retractable covers. At the inlet end of the sedimentation tanks and where the scum removal occurs, frequent access for visual inspection and hosing is required. This area will have motor operated fibreglass covers that can be operated easily.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 The two grit classifiers and hopper will be sealed and air extracted for treatment, significantly reducing the odour impacts from this area. The ventilation rate for the existing covered areas will be increased from the current level to prevent fugitive emissions and corrosion of the concrete and steel works underneath. The foul air extracted will be treated in four OCUs with biotrickling filters. The treated air will be discharged via a stack some 20 m above ground level.
Biotrickling filters can treat high odour loads and have relatively low operating and maintenance costs, have reduced chemical consumption and have a small footprint in comparison with other treatment systems. These performance criteria are useful, given that available space for the OTF is limited. The technology has been proven at Brooklyn and Warriewood WWTPs.
This option has:
• low odour risk
• lowest cost for covering
• provides sufficient access to hatches
• relatively simple design
• proven technology
• relatively low visual impact.
3.5 Ecologically Sustainable Development
The most common and broadest definition of Ecologically Sustainable Development (ESD) is ‘development that improves the quality of life, both now and in the future, in a way that maintains the ecological processes on which life depends ’ (Environment Australia, 1992). The Project has been considered in accordance with the four principles of ESD as outlined in section 6(2) of the Protection of the Environment Administration Act 1991 and Schedule 2 of the EP&A Regulation.
Sydney Water’s Ecologically Sustainable Development Policy rests on the four principles outlined below and Sydney Water is committed to ensuring that these principles underpin its decision- making processes and are incorporated into operational activities.
The Odour Management Project at Cronulla WWTP has addressed the four ESD principles as detailed below.
Precautionary principle
The Project will not result in serious or irreversible environmental damage. There is no scientific uncertainty relating to the Project. Data from other WWTPs show that the preferred option successfully manages noxious odours and implementation has not resulted in serious or irreversible environmental damage.
Instead, the Project will ensure that the DECCW’s ‘no nuisance’ criteria will be met and the amenity levels in the local community will be increased.
Intergenerational and intragenerational equity
The Project will help ensure that the needs of the future generations living in the area will be adequately addressed by providing improved air quality in the vicinity of the WWTP. The Project will use resources judiciously and is unlikely to negatively impact the health, diversity and productivity of the environment.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 Conservation of biological diversity and ecological integrity
The Project is unlikely to have a significant impact on biodiversity or ecological integrity, as the works will be carried out on existing cleared areas within the operations area of the WWTP. Appropriate safeguards will be in place during construction and operations to ensure impacts to areas outside the operations area will be minimised.
Improved valuation and pricing of environmental resources
Economic, social, environmental and financial criteria were used to determine the preferred option. The best value for money option became the Project. Future users of the service will pay the costs of the improved service.
Sydney Water, as part of its commitment to sustainable development, has assessed the Project in relation to theoretical ESD development options. The project is assessed as Alternate 3: Repair and Improve. Refer to Table 3.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011
Table 3: Assessment of alternatives with respect to Ecologically Sustainable Development (ESD)
Options Performance against principles of ESD General issues Conclusion
Precautionary Intergenerational Conservation of Improved valuation, principle and biodiversity & pricing & incentive intragenerational ecological integrity mechanisms (see note 1) equity (see note 3) (see note 4) (see note 2)
Alternative 1: This option would be This option could have This option will not Sydney Water may be Although economical in This option is unsuitable, Do Nothing unlikely to meet negative impacts on threaten the required, as the odour the short-term, this as it does not comply This alternative would DECCW’s ‘no the health and well- conservation of polluter, to pay fines option could result in with Sydney Water’s result in ‘business as nuisance’ criteria. being of the local biodiversity or for not complying with greater expenditure in legal requirements and usual’ with on-going It could result in community and could ecological integrity. regulatory the future. Local amenity social commitments. odour issues at the community complaints result in additional requirements. Sydney levels will be negatively WWTP and adjacent It does not comply costs in the future. Water would be impacted. Sydney areas. with SW’s Odour expected to make the Water’s public standing Management Strategy. necessary and customer focus improvements. would be questioned. This option could result in additional amelioration work later Alternative 2: No critical failure has This option would This option could Replacement would Replacement could be The replacement option Replace Assets after occurred and Sydney result in increased result in additional use result in higher seen as sub-optimal is not cost effective and Critical Failure Water has no reason waste and resource of resources and construction and asset, financial and does not meet ESD to believe that critical usage and cause an waste generation but operational environmental principles. This alternative would failure’ is likely. . unnecessary financial is unlikely to result in management costs. management. mean the removal and Complete replacement burden on future loss of biodiversity or replacement of the PST of existing users. ecological integrity, and associated infrastructure is not infrastructure and of necessary and would the existing odour be expensive and management facility. could compromise the
EPL.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011
Options Performance against principles of ESD General issues Conclusion
Precautionary Intergenerational Conservation of Improved valuation, principle and biodiversity & pricing & incentive intragenerational ecological integrity mechanisms (see note 1) equity (see note 3) (see note 4) (see note 2)
Alternative 3: The Project will not The Project will use The Project is unlikely The Project provides The are no significant The Project is cost Repair and Improve result in irreversible resources judiciously; to impact on the best value for ESD issues associated effective, meets ESD The Project will environmental odour levels will conservation, money of the options. with this Project. criteria and responds to repair and improve damage. Data from improve as will biodiversity or It has the lowest regulatory requirements. existing other WWTP shows general amenity ecological integrity. maintenance costs. It will provide the best infrastructure and the Preferred option levels. The Project Current ecosystems Future users of the value for money of the facilities successfully manages enhances benefits for will be conserved. service will pay costs. options. noxious odours. It has current and future This option will resulted in low users. improve social and environmental impact. amenity values.
1 The Protection of the Environment Administration Act 1 991 and the EP&A Regulation define the precautionary principle as ‘if there are threats of serious or irreversible environmental damage, lack of scientific certainty should not be used as a reason for postponing measures to prevent environmental degradation’. 2 Under SW ESD Policy, the Protection of the Environment Administration Act 1991 and the EP&A Regulation, the principle of intergenerational and intragenerational equity can be stated as ‘the present generation should ensure that the health, diversity and productivity of the environment is maintained or enhanced for the benefit of present and future generations’. 3 The principle requires that the diversity of genes, species, populations and their communities, as well as the ecosystems and habitats they belong to, are maintained or improved to ensure their survival (Sydney Water, 1995). 4 This principle involves placing a monetary or social value on the environment, which ultimately increases its value. For example, pollution and future exploitation can be controlled under the ‘polluter pays’ principle, whereby polluters or those who destroy or use the environment are responsible ad accountable for restoring it to its previous or natural condition (Sydney Water, 1995)
The Project repairs and replaces existing infrastructure and is assessed as fulfilling the requirements of Alternative 3:Repair and improve.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011
4. Description of the proposed work and activities
4.1 Objectives of the project
The objectives of the Cronulla WWTP Project are to:
• significantly reduce the risk of odours impacting on the surrounding community
• achieve the DECCW ‘no nuisance’ odour criteria of 2 OU, 99% of the time during plant operation
• improve the reliability and extend the economic life of the existing infrastructure.
The upgrade of the WWTP is part of Sydney Water’s ongoing Odour Management Strategy. Its timing has been influenced by rezoning of land adjacent to the plant from industrial to residential uses. This is expected to bring sensitive receptor much closer to the plant than is currently the case.
4.2 Scope of work
The Cronulla Odour Management Project includes:
• covering the odourous areas of the plant not covered at present
• extracting foul air from under the covers
• treating foul air in four biotrickling odour control units and dispersing treated air via a stack
• refurbishing and corrosion protecting of the relevant existing infrastructure.
Details of the Project are as follows:
• covering the odourous areas of the plant not covered at present:
− the main body of the PST will be covered with structurally supported, retractable fabric covers where none exist at present. The new covers will be retractable for full access to the tanks and they will seal to contain odours. These covers will have 12 to 15 years life expectancy and they are cost effective on a life cycle cost basis.
• extracting foul air from under the covers:
− foul air will be extracted, using large fans, from under the covers. It air will be transported to the OTF via purpose-built ductwork. The grit handling facilities consist of two grit classifiers, a grit hopper and an open unloading skip bin. The grit classifiers and hopper will be sealed and noxious air extracted for treatment in the OTF
− the existing ventilation rates will be increased to achieve better ventilation (10-16 air changes/hr) and higher extraction rates of noxious air over the covered primary processes.
• treating foul air in four biotrickling odour control units and dispersing treated air via a stack:
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 − a new OTF with four biotrickling OCU will be constructed to treat foul, or odourous, gasses
− the OCUs will be installed on a concrete pad. Each OCU will have a diameter of approximately 4 m and a height of 12 m. Access platforms will be installed to key parts of the OTF, thereby ensuring maintenance and other activities are relatively easy to perform and safety is not compromised
− each OCU will contain a biotrickling filter system to treat the foul air from the PST and other areas. The biotrickling system was selected due to its abilities to remove specific odours from the site
− a stack will be constructed adjacent the OCUs to discharge air treated in the OCUs. Ductwork will connect the stack and OCUs. The stack will be placed on a frame resulting in an outlet height of 20 m. Treated air will be discharged into the atmosphere using the physical properties of the stack aided by large fans
− the OCUs, ducts and stack will be painted a matt, dark grey-green colour.
• refurbishing and corrosion protecting of the relevant existing infrastructure:
− the inlet channel will be refurbished with low profile fibreglass covers. These covers will contain access hatches where required. The covers will be trafficable and will have a 20 year life expectancy
− the covers in scum removal areas will be replaced with fibre-glass motorised covers to allow easy and frequent opening for inspection etc. The existing covers on the grit tanks, PST launders, PST effluent bypass channels, interstage pumping station, and sludge holding tanks will also be renewed
− the existing ductwork for the PST area will be replaced where the capacity is inadequate for the increased ventilation rates. The majority of ductwork at the front end of the PST will be replaced. The ductwork from the grit tanks, gravity thickener, digester feed well will be unchanged
− the concrete surface below the covers, exposed to a corrosive environment, will be coated with epoxy to prevent corrosion. Corroded concrete and steelwork under the existing covered structures will also be replaced
− upgrades to utilities, like drainage, water and power lines, will be installed, generally underground. Some existing utilities may need to be moved from the area
− additional equipment, like fans and pumps, lights and switches, will be installed within the OTF footprint.
For a graphic 3D model of the proposed OTF, refer to Figure 8.
4.3 Proposed activities
Construction activities will involve the following:
Preconstruction
The main activities to be carried out prior to construction typically include:
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 • finalising the detailed design
• preparing and obtaining approvals for the CEMP and any other approvals required
• liaising with the plant manager, environmental representative and key stakeholders as per the Communications Strategy
• geotechnical investigations, building condition assessments and site survey
• notifying all interested parties of the start of works
• ordering, delivering and storing of materials and equipment
• undertaking temporary installation works.
Construction
Construction activities will be planned and scheduled to minimise disturbance to the site, to the operations of the WWTP and to its EPL compliance.
Construction activities will include:
• training, managing and monitoring environmental aspects
• installing temporary works
• excavating as required e.g. for services, building footings, drainage lines
• constructing site offices, amenity buildings, service connections, etc.
• constructing the OTF slab and stack footings
• installing the OTF including the OCUs, scaffolding, the manifold, ducts etc
• installing a 20 m stack
• managing and reporting on waste and resource and energy usage
• managing safety, access and traffic
• managing hazardous substances
• fabricating / assembling on-site as required, e.g. duct and vent systems
• managing construction dewatering, including testing, treatment and reuse
Commissioning
Commissioning will include the following:
• factory tests
• installation/ dry test
• training tests
• start-up tests
• reliability and process performance tests.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 An integrated, planned approach will be adopted for testing and commissioning the installations. Commissioning will be implemented in accordance with the Sydney Water approved Commissioning Plan for the works. The process will include keeping up-to-date test records that are available for review and/or audit. In the case of test failure, action will be taken to correct the fault and the test will be repeated until satisfactory standard has been achieved.
Post construction
Post construction activities will include:
• site disestablishment e.g. removing site offices, services, etc.
• site remediation to pre-construction conditions
• waste management as required.
Sydney Water will incorporate relevant operational mitigation measures into the existing operational management system at the commencement of the operational phase.
4.4 Materials and equipment
Construction
Equipment to be used during construction includes:
• excavators
• cranes and elevated work platforms and scaffolding
• compactors and rollers
• welding equipment
• concrete trucks and other heavy duty trucks
• chemical, delivery and waste removal trucks.
Types of materials to be used during construction include the following:
• concrete for civil structures
• galvanised steel for structural steel work
• stainless steel / aluminium for associated steel work
• fibreglass reinforced plastic (FRP) for the fibreglass covers and ductwork
• aluminium
• biotrickling media to be installed in the OCUs.
Operations
Types of equipment to be used permanently on site include the following:
• fans, heaters and pumps
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 • biotrickling OCUs and associated ducting and platforms
• electrical equipment and valves.
The types of chemicals to be used during operations include:
• a biotrickling medium, similar to compost
• a nutrient mixture of nitrogen and phosphorus for the biomass within the biotrickling filters.
These chemicals are not identified under the Dangerous Goods Act. The storage and waste management of the biotrickling medium will be managed using standard Sydney Water procedures and are not anticipated to result in significant environmental impacts.
4.5 Work sites, access and vehicle movements
Access to the site will be via the Cronulla WWTP entrance on Captain Cook Drive. Site sheds and amenities will be located in the old biosolids loading slab to the east of the construction site. Private construction vehicles will be accommodated in parking areas within the operations area. Vehicular movements will be defined prior to the start of construction and managed during construction to ensure a safe working environment.
4.6 Work times and timeframes
Table 4 shows the estimated timeframe for the completion of project activities.
Table 4: Project timeframe
Task Completion date
Award of design contract December 2010 Design completion August 2011 Contracts for construction, by Alliance September 2011 Procurement of biotrickling filters January 2012 Construction start October 2011 Construction completion Summer 2012 Commissioning October/ November 2012
It is estimated that the design phase will take approximately eight months. Achieving the 12-month timetable above is dependent on the procurement process, as some items may need to be sourced overseas. Implementation of the Project, including commissioning, is expected to take 12 to 18 months.
Construction working hours will be 7 am to 6 pm Monday to Friday and 7 am to 1 pm (or 8 am to 1 pm if audible at residential premises) on Saturday. Night work may be required for some activities, including the transportation of the OCU, the fabricated stack and ductwork to reduce traffic congestion on the roads. Operating hours will not change from the current hours. Night work is a standard operational requirement at WWTPs.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 4.7 Changes to the Project
If the proposed work changes during detailed design or following award of the contract, a supplementary environmental impact assessment may be required. Any changes to the Project as described in this document are to be considered in terms of Sydney Water’s Environmental Management System Environmental Impact Assessment Alterations Procedure .
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011
5. Existing environment, potential impacts and measures
The treatment plant is located on the Kurnell Peninsula near the residential suburbs of Taren Point, Caringbah, Cronulla and Kurnell. These suburbs contain shopping, industrial and recreational areas. A number of significant nature reserves are also located on the Peninsula. (Figure 5).
This chapter outlines the existing environment, identifies impacts and appropriate safeguards for the proposed construction and commissioning, as well as for the operation of the Project.
Figure 5: The Cronulla WWTP and adjacent areas
5.1 Topography, geology and soils 5.1.1 Existing environment
Topography
The Cronulla WWTP is located on a ridgeline created by a secondary dune which lies between Botany Bay on the north and Bate Bay on the south. The ridge rises sharply to RL30 on the
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 northern plant boundary. A narrow strip of alluvial soils adjacent Botany Bay accommodates Captain Cook Drive, the access road to the WWTP.
Geology and soils
Hawkesbury Sandstone underlies the Kurnell Peninsula, however it lies at a depth of 10-15 m below the WWTP. The dominant sandstone surface deposits are intertidal flats and swamps on the Botany Bay shore. Dune deposits are gradually overriding these flats and swamps from the south.
The WWTP dune consists of Botany Bay (Quaternary) sands with podzol (grey, leached organic) soils developed on the top of the dune. The soils are predominantly windblown medium-fine sands that are erodable once disturbed.
Acid sulphate soils
Acid sulphate soils (ASS) are common in marine and estuarine sediments less than 5 metres above sea level. Traces of sulphate within the soils, when exposed to air through excavation or drainage, can form sulphuric acid. The acid reacts with clay minerals and dissolves metal particles in the soil, such as iron or aluminium. Acid and metal are often toxic to flora and fauna.
The SSC’s ASS risk maps indicate a low probability of ASS on the operations area due to its elevation coupled with a low water table. The location of the proposed works has a Class 5 risk of ASS, meaning that it is unlikely that ASS will be encountered during excavation.
Contamination
The soils in the operational area are classified as ‘disturbed terrain’. They may contain some contamination from previous works and from operation of the treatment plant. No site contamination has been identified at present. 5.1.2 Impacts and environmental mitigation measures
Construction
The proposed work will involve excavation for the OFT and stack and possibly for access. It is estimated an area approximately 300 m² will be excavated to a depth of approx 1.0 m. The depth will be determined by the nature of the underlying material, which is generally classified as ‘disturbed terrain’. The proposed work would include backfilling excavated portions of the operations area, as required.
Geological conditions would not be affected, given the anticipated depth to bedrock.
The potential impacts to soils include:
• erosion of soil in the excavated OTF area
• generation of sediment-laden runoff from unprotected soil stockpiles and excavated ground
• soil and runoff contamination from the spillage of chemicals and fuels
• polluted runoff entering the surrounding stormwater system.
Spoil would be stockpiled onsite during the construction phase. There is potential for soil erosion and generation of sediment-laden runoff from unprotected spoil stockpiles and excavated ground.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 The implementation and effective maintenance of soil erosion controls will be required to minimise potential for polluted runoff into local waterways and bushland areas. There is a potential for soil and runoff contamination from chemical or fuel spills during the construction phase of the Project. The implementation of the following measures will minimise potential impacts:
• installation of appropriate erosion control measures to control runoff from the work site
• erosion and sediment control measures to be consistent with those specified in DECCW‘s ‘Urban Erosion and Sediment Control Manual ’ (DLWC, 1992) or the NSW Government's 'Blue Book ' (4th Edition, 2004) on erosion and sediment control
• erosion and sediment control measures would be established before work begins and maintained in effective working order throughout the duration of the work and until the work site has been stabilised
• surfaces would not be left exposed for extended periods and would be progressively resealed or revegetated as early as possible
• equipment, plant and materials will be situated in designated lay-down areas where they are least likely to cause erosion
• stockpiles of soils or fill will be tested and covered or bunded and managed in an appropriate manner to prevent dust, erosion and sediment runoff
• visual monitoring of stockpiles will be done to reduce the risk of sedimentation and dust generation
• ‘clean’ surface runoff will be diverted around and away from work areas to prevent erosion
• excavated soil would be re-used in the backfilling where possible to minimise the need for disposal of spoil
• spoil must be tested for contamination prior to removal from work site and any contaminated spoil will be disposed of in an approved facility
• disturbed areas will be landscaped, revegetated and stabilised following construction, where necessary.
Operation
Temporary stockpiles of excavated materials will be used to backfill on work site where possible. Any excess materials that cannot be used on site, will be tested, treated or disposed of at an appropriate disposal facility. Positioning of any additional permanent stockpiles with excess spoil will require review of surface hydrology and flooding patterns to ensure placement will not affect the predicted flood regime.
Operational impacts of the Project are expected to be minor. The work site would be revegetated if necessary, using large plant material, and stabilised following construction. 5.1.3 Conclusion
Provided that the appropriate erosion, sedimentation and contamination measures specified on 5.1.2 are implemented prior, during and after construction, the impacts on topography, geology and soils as a result of the Project will be minimal.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 5.2 Water and drainage 5.2.1 Existing environment
The water table lies some 10 m beneath the Cronulla WWTP site. Drainage from the WWTP into Botany Bay or to the sea or any other area is unlikely due to two factors: the high infiltration capacity of the Botany Sands and the ‘first flush’ collection system within the operations area.
Surface water
The WWTP has a first flush system in place where stormwater resulting from the first 10 mm of rainfall and all wash-down water is directed back into the head of the treatment works. Treated water is then discharged into the ocean at Sydney Water’s ocean outfall at Potter Point.
Wastewater and effluent quantity and quality
The Cronulla WWTP, which has an ADWF of 54 ML/d, originally provided only primary treatment of wastewater. In 2001 the treatment was upgraded to a tertiary level.
The treated effluent is discharged via a gravity pipeline to a point 5.2 km away from the plant at an outfall off Potter Point on the south side of the Kurnell Peninsula. The outfall discharges approximately 6 m below the surface.
The following table identifies key chemical and other pollutant levels permitted by the EPL for effluent discharge by the WWTP. The table also includes the monitored levels of these pollutants from 2007/8 to 2009/10.
Table 5: Licence (EPL no. 1728) chemical load limits and actual load measures at Cronulla WWTP
Load limit 2007/ 2008/ 2009/ Assessable pollutant (kg/year) 2008 2009 2010
Biochemical oxygen demand 319,010 84,719 37,475 72,774 Nitrogen (Total) 735,110 551,882 506,876 457,876 Oil and grease 110,000 626 673 632 Phosphorus (Total) 243,090 219,060 152,712 137,820 Total suspended solids 305,000 101,980 16,407 64,859
The table shows that performance of the WWTP over the past three years has not exceeded the EPL chemical load targets.
Coastal water quality
The closest swimming beach to the Cronulla outfall is Boat Harbour, which is approximately 1.2 k west of the outfall. Other beaches in the area include Greenhills Beach, Wanda Beach, Elouera Beach, North Cronulla, South Cronulla, Shelly Beach and Oak Park.
Beach water quality samples are regularly taken by DECCW and tested for the presence of indicator bacteria (Faecal coliform spp. and Enterococci) to determine the suitability for swimming.
The DECCW’s State of the Beaches Report 2009-2010 (DECCW 2010) reports that Greenhills, Elouera and Shelly Beaches were graded as ‘Very Good’ with regard to swimming suitability. In addition, Boat Harbour, Wanda, North Cronulla, South Cronulla and Oak Park were all graded as
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 ‘Good .’ No beaches in the Southern Sydney Beaches area were classified as ‘Fair,’ ‘Poor,’ or ‘Very Poor.’ 5.2.2 Impacts and environmental mitigation measures
Construction
The Project is unlikely to significantly alter run-off or drainage patterns within the WWTP or on adjacent lands. The stormwater system would be designed inline with the existing first flush system ensuring that only clean runoff discharges to local waterways or the ocean.
In addition to the mitigation measures identified in Section 5.1.2, the following safeguards would be implemented to minimise the potential risk of pollution to waterways. These measures would be applied to all work areas and incorporated into the CEMP. They are as follows:
• the area of exposed surfaces will be minimised and progressively rehabilitated
• no excavation would take place in or immediately after heavy rainfall
• surface runoff from all other areas would be directed to the head of work for treatment in the WWTP
• appropriate use of sediment controls (as described in Section 5.1.2).
Operation
Wastewater
Operation of the refurbished OTF will require industrial water of approximately 30 kL/day on average, and the amount of drained from the OCF is 28 kL/day on average. The liquor drained from the OCUs flows into a sump and is piped to the head of work for re-treatment. The increase in wastewater treated by the WWTP is approximately 0.052% of the daily dry weather amount. Subsequently, the impact on ocean water quality is not expected to be significant.
It is unlikely that increases in wastewater volume or toxicity from the Project during operations would impact the local surface water systems.
Coastal water quality
An impact on water quality and marine flora and fauna is not considered likely.
Discharges to the ocean from the Cronulla WWTP are regulated by the EPL and ongoing monitoring of the wastewater treatment system performance is required by the licence.
Effluent quality, including concentrations of toxicants of concern to marine species, is not expected to change given the nature and amount of drainage discharges relating to the Project. Effluent toxicity testing, as required by the licence, will validate the conclusions detailed in the REF.
Stormwater / groundwater
It is not considered likely that significant impacts on groundwater will occur during the operational phase of the project. However, standard management of stormwater flows within the WWTP will ensure that impacts would be minimised.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 5.2.3 Conclusion
The proposed mitigation measures, as described in section 5.2.2, would prevent or minimise the risk of pollution to surface and groundwater. Collection of surface water and the appropriate treatment of wastewater prior to discharge ensure that pollution of nearby watercourses should not occur.
Impact on ocean or bay water quality from the Project is not anticipated and EPL compliance will be maintained.
Figure 6: The Cronulla WWTP, the proposed development area and Towra Point reserves
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011
5.3 Flora and fauna 5.3.1 Existing environment
Cronulla WWTP is located within the vicinity of a number of environmentally significant areas, for example, Towra Point Nature Reserve and aquatic sanctuary (Figure 6). The nature reserve wetlands are of international significance and are listed under the Ramsar Convention on Wetlands
The Cronulla WWTP includes a natural area with two EEC as well as coastal dune heath and revegetated areas. A constructed wetland, Keegan’s Basin, is also located within the natural area. It is an ephemeral wetland that was revegetated after it was cleaned out during the upgrade of the WWTP in 2001.
The WWTP’s operations area, where construction will take place, is highly disturbed and only a limited amount of vegetation is to be found. Most, if not all, has been planted. The operations area is fenced.
A number of flora and fauna surveys were undertaken from 1996 to 2003. A fauna and flora study was not undertaken for this Project due to the lack of suitable habitat and the nature of the operations area. It features noise and vehicles, a lack of drinking water and hot and dusty conditions.
Flora
The two EEC located within the natural area of the WWTP are:
• Kurnell Dune Forest – listed as a Threatened EEC under the TSC Act
• Littoral Rainforest – listed as a Threatened EEC under the TSC Act and as a Critically Endangered Ecological Community under the EPBC Act.
The Kurnell Dune Forest is a low, open sclerophyll forest community typically found on sand and often in association with sclerophyll heath and scrub. The Forest contains a wide range of vegetation species, many relatively widespread in the Sydney region, eg Eucalyptus botryoides and E. robusta , Hibbertia scandens , and Lomandra, Pandorea and Pimelea species.
The Littoral Rainforest is a small area of remnant vegetation located to the west of the clarifiers. Species recorded in the Rainforest include Tuckeroo ( Cupaniopsis anacardioides ) and Poa affinis, which are fairly common and widespread in the Sydney region. The remnant vegetation near the operations area was fenced and rehabilitated using native tube stock after the 2000 WWTP upgrade.
Fauna
The natural area potentially contains six threatened fauna species. One of the six species, the Green and Golden Bell Frog (GGBF) (Litoria aurea), is listed as Endangered under the TSC Act and as Vulnerable under the EPBC Act.
Other frog species that may be present within the natural area include:
• Wallum Froglet (Crinia tinnula) – listed as Vulnerable under the TSC Act
• Common Eastern Froglet (Crinia signifera)
• Jervis Bay Tree Frog (Litoria jervisiensis)
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 • Brown-striped Frog (Limnodynastes peronii).
Frog call-back surveys were undertaken in July and September 2010. Cane toad calls were also played. The time of year was not ideal and no frog call-backs were heard. However, GGBF have been heard and seen on operational areas over the past five years, although sightings have become increasingly rare over the past two years (anecdotal evidence provided by personal comments from WWTP staff). No GGBF was sighted during the 2008/2009 Digester Lid construction. The frog call-back survey did not elicit a call from the cane toad.
The GGBF is not likely to constitute a viable population under the TSC Act. Habitat conditions are generally unsuitable and breeding in the operations area is considered unlikely due to the lack of suitable breeding areas.
There is a potential for the migrant Grey-headed Flying Fox (GHFF) (Pteropus poliocephalus) to be found within the natural area of the WWTP. The GHFF is listed as Vulnerable under both the TSC Act and the EPBC Act. The Eastern freetail-bat (Mormopterus norfolkensis), Yellow-bellied sheathtail-bat (Saccolaimus flaviventris) and the Eastern bentwing-bat (Miniopterus schreibersii oceanensis) may also occur on operations area. These bats are listed as Vulnerable under the TSC Act.
None of the flying fox species listed above is known to exist in the operations area nor were they listed in previous surveys.
Migratory and native bird species frequent the Kurnell Peninsula and can be seen flying overhead. It is unlikely that the operations area is used by birds other than for limited foraging. 5.3.2 Impacts and environmental mitigation measures
Construction
Construction and commissioning work will be confined to the operations area. Construction activities, given the amount of noise and vehicular traffic expected on the operations area, could impact fauna if present.
No loss of native habitat, including EECs, is anticipated.
Planted Banksias trees located adjacent to the OTF will be trimmed and a number may need to be removed during construction for access purposes. The implementation of the following mitigation measures would minimise the potential for disturbance to flora and fauna:
• vegetation clearance and disturbance will be kept to a minimum
• where possible, clearing will be limited to trimming of branches rather than the removal of whole plants
• in the event vegetation needs to be removed, it will be replaced with planting similar species in other areas of the WWTP
• exclusion fencing (frog fence) will be installed before work begins to prevent small animals, particularly frogs, entering the work areas, and regular checks for animals will be undertaken
• staff will be inducted before work begins regarding the potential for threatened species on site, conservation measures and reporting procedures (including native animal sightings), especially for the GGBF, the GHFF, Littoral Rainforest and Kurnell Dune Forest
• handling of animals is to be avoided.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 Environmental risks to the Towra Point area are considered unlikely due to the distance from the Sydney Water site. In addition, standard soil, water and drainage measures will be carried out to minimise impacts should they occur as a result from the Project. Refer to Sections 5.1 Topography, geology and soils and 5.2 Water and drainage for additional impact mitigation information.
Operation
Standard operating procedures at the WWTP will continue. Given the location and nature of the work, impacts to flora and fauna are considered unlikely, and standard procedures are considered sufficient to manage potential impacts.
The WWTP will continue to comply with the EPL requirements. 5.3.3 Conclusion
The proposed work is unlikely to have a significant impact on flora and fauna species at the WWTP, provided the safeguards outlined in Section 5.3.2 are implemented. The proposed work will occur within the existing operational areas of the WWTP, and would generally be limited to trimming of a few planted trees species.
5.4 Air quality 5.4.1 Existing environment
This Project aims to ensure on-going compliance with DECCW’s ‘no nuisance’ criteria. Permitted odour levels are not specified in the EPL issued by DECCW but the Project will comply with one of the EPL objectives in relation to continuing improvement in environmental performance.
The Project will also implement the aim of Sydney Water’s Odour Management Strategy to significantly improve odour mitigation at the Cronulla WWTP.
Air quality is generally considered in terms of odour and dust. As the majority of the Cronulla WWTP is either hard-stand or vegetated, dust is generally not an issue for the current operation of the plant. However, dust from the adjacent barren dunes occurs, especially in windy conditions.
The WWTP is a source of odour due to its normal operational activities. The odour impact from the plant has the potential to extend to development on adjacent land.
Sydney Water engaged consultants, CH2MHILL, in 2008, to design improved odour management facilities at the WWTP. The original design consisted of refurbishing the existing infrastructure responsible for 50% of odourous emissions as well as building an OTF. The OTF was designed with four biotrickling OCUs vented through individual stacks on each OCU, making a total height of approximately 15 m.
Odour modelling was subsequently undertaken using the CALPUFF modelling system to simulate odour dispersion into the atmosphere. The modelling showed that the height of proposed stacks was not sufficient to effectively disperse odours and that increasing the height of the stacks to 20 m above ground level would improve dispersion.
Changes were made to the design. The four stacks were replaced with a consolidated stack of 20 m. The design will achieve DECCW’s ‘no nuisance’ criteria during normal operations. Refer to Figure 7 for existing and modelled future odour impacts.
Whilst increasing the stack height from 15 to 20 m may increase visual impact it, will have substantially less visual impact than four stacks each 20 m high.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011
Legend: ______Property Boundaries of Australand and Breen land
______NSW DECCW Odour Guideline for Cronulla WWTP - 2010
______NSW DECCW Odour Guideline for Cronulla WWTP – after project completion Approximate area of new residential development
+ Nearest odour receptor - after completion of Australand residential development
Figure 7: Cronulla WWTP showing existing and post implementation odour impacts during normal operations and as identified by the Sydney Water CALPUFF model 5.4.2 Impacts and environmental mitigation measures
Construction
Construction work has the potential to generate dust, odour and vehicle emissions. Dust could result from excavations, materials delivery, spoil stockpiles, and vehicle movements. Excavations could mobilise airborne pollution.
As the WWTP is elevated relative to Captain Cook Drive, dust and airborne pollutants could drift across to the road from the work site depending on the prevailing winds.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 There will be an increase in truck movements in and out of the WWTP during construction, however impacts to air quality are expected to be minimal. For additional traffic information refer to 5.9 Traffic and access. Increases in dust and fuel emissions will reduce once construction ends and operations begin.
The WWTP will operate normally during construction. However, odour from the primary treatment process may increase slightly when the covers are removed from the inlet channels and the scum removal area to allow the replacement work to occur. This impact is expected to be minimal, short- lived and confined to the construction phase only. The implementation of the following mitigation measures will minimise the potential for impacts on air quality associated with construction:
• visual monitoring of dust generation will occur and dust suppression measures such as water spraying will be used, especially if windy
• odour impacts will be minimised by reducing the time taken to replace the covers
• all work vehicles and machinery will comply with DECCW emission requirements and vehicle use on unsealed surfaces will be avoided
• vehicles and machinery will be maintained properly and not left idling when not in use.
Operation
During operation of the Project, air quality in and around the WWTP is expected to improve considerably. Modelling shows the Project will result in compliance with DECCW’s ‘no nuisance’ criteria during standard operating conditions. Refer to Figure 7 for existing and modelled odour contours.
The stack is at the optimum height to ensure odour dispersal, however, it will result in an increased visual impact. 5.4.3 Conclusion
Although there is potential for adverse air quality impacts during construction, the implementation of mitigation measures outlined in Section 5.4.2 will ensure any impact is short term and minor. Once operations, the Project will result in a significant improvement to odour levels at the WWTP and within adjacent areas.
5.5 Noise and vibration 5.5.1 Existing environment
The existing ambient noise environment at the nearest residences, some 1.5 km away, is typical of a suburban area with light traffic noise and intermittent general residential noise.
The EPL for Cronulla WWTP does not include criteria for operational noise limits. The POEO Act and Regulations define types of noise and vibration, their measurement and mitigation. All construction must comply with both noise and vibration standards and guidelines including the Interim Construction Noise Guideline (DECCW, 2009). Operational noise criteria are prescribed in the NSW Government’s Industrial Noise Policy (INP) (2000).
In the vicinity of the WWTP, main noise sources include light local traffic on Captain Cook Drive, operational processes of the WWTP and ocean noise. At night noise from the ocean is more
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 evident as other sounds like traffic noise are reduced. Minor vibration due to operation of key equipment, eg fans and pumps, has been noted on operations area on occasion but the effect was not assessed as significant.
The nearest sensitive noise receptor is located at the Cronulla High School, at a distance of approximately 1.5 km from the WWTP. No noise complaints have been received at the plant and as such, current operational noise at the WWTP is not considered to be an issue. 5.5.2 Impacts and environmental measures
Construction
Potential noise and vibration impacts from the construction of the proposed works include:
• noise from excavation and construction work including the use of power tools, whistles and signalling crane operators, and from moving equipment and materials around the work site
• noise from demolition
• noise and minor vibration from trucks and vehicles such as deliveries and running vehicles.
The construction work would occur in the operations area within the WWTP boundaries. Work is expected to take up to 18 months to complete. Prevailing noise and vibration levels have the potential to increase during construction. All work will be undertaken in accordance with the DECCW Interim Construction Noise Guidelines (DECCW, 2009), such as construction is specified for working hours. Potential noise and vibration impacts are expected to be short term only and would cease when construction finishes.
The following safeguards will be implemented to minimise noise impacts during construction:
• work and deliveries should only occur during the following times:
− Monday to Friday 7 am to 6 pm
− Saturday 7 am to 1 pm (if inaudible at residential premises) or 8 am to 1 pm (if audible at residential premises)
− Construction work or deliveries must not occur on Sundays or public holidays without prior Sydney Water approval and public notification.
• where night work is required, efforts should be made to avoid or minimise noise by limiting work to waking hours
• limiting the amount of noise through the use of quieter methods such as the use of radios rather than whistles for crane operator instruction.
Operations
A minimal increase in operation noise levels is expected when the new OTF is operational. However, noise management measures like installing covers to fans (or baffles) and pumps may reduce operating noise impacts and ensure compliance with the POEO Act and Regulations. No increase in vibration is anticipated. 5.5.3 Conclusion
The proposed construction and operational work is unlikely to result in significant construction noise or vibration impacts. Impacts from construction and operation of the Project on sensitive
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 noise sites, like the high school, are expected to be minimal. The implementation of mitigation measures will further ensure that noise and vibration impacts are not significant.
5.6 Energy and chemical usage 5.6.1 Existing environment
Energy
Sydney Water recognises global warming as a significant risk to the environment and has an ongoing commitment to achieving environmental sustainability in its operations and to carbon neutrality by 2020.
To this end, Sydney Water has installed cogeneration plants at suitable wastewater treatment plants. Methane generated on site is used to create energy for use on the site. Cronulla’s cogeneration plant supplied 580 MWH in 2007/2008, and is forecast to produce 2,714 MWh over 2010-2011. In 2009/2010 the WWTP used 10,285 MWh of which 21% was generated on site at the cogeneration plant. Electrical energy consumption at the WWTP is primarily associated with pumps which have the highest mains energy usage.
Chemicals
SEPP 33 – Applying SEPP 33 (DoP 2008) provides criteria against which potential industrial development must be assessed to determine if the work is potentially hazardous or offensive. The criteria specify threshold limits on the quantities of hazardous material to be stored and the level of transportation of these materials. Threshold limits determine whether a preliminary hazard analysis (PHA) is required. The Project will not breach the threshold. Furthermore, SEPP 33 does not apply to projects assessed under Part 5 of the EP&A Act, so no PHA is required.
Wastewater treatment plants require a variety of chemicals to reduce foul odours. For example, ferrous chloride solution (Odourlock) is used to reduce the ‘rotten egg’ smell caused by hydrogen suphide (H 2S). Cronulla WWTP currently stores a variety of chemicals onsite for the operation of the plant. They include:
• ferrous chloride solution
• sodium hydroxide (50%)
• sodium hypochlorite (12.5%).
Cronulla WWTP holds a WorkCover Dangerous Goods Licence that permits storage of dangerous goods in approved quantities. Chemical storage is a ‘scheduled activity’ under the POEO Act and is also licensed in the current EPL for Cronulla WWTP. 5.6.2 Impacts and environmental mitigation measures
Energy and greenhouse
The completion of the proposed work will result in a minor increase in the current on-site WWTP energy consumption. Energy consumption relating to the Project is not expected to be significant in relation to current usage. All components for the Project will be designed and procured through a
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 process that incorporates criteria consistent with Sydney Water policies, including the Ecologically Sustainable Development Policy and Energy Management Policy and other obligations. In addition, Prior to finalising detailed design for the Project, the designer will identify measures to reduce on- site energy consumption during operation. Where practicable, such measures will be incorporated into the design and will be operational at the time of commissioning.
Greenhouse gas emissions and energy consumption resulting from construction equipment is anticipated to be minimal. Energy consumption from the operation of the OTF is also not anticipated to increase significantly. New energy uses include the biotrickling system, new pumps and fans to aid the transfer of gases.
Overall, the proposed work is unlikely to significantly increase greenhouse gases or create a significant increase in energy usage at the plant. However, construction energy use will be reported as required under the National Greenhouse and Emissions Reporting Act 2007 (NGER).
Chemical use
Construction
Chemical storage requirements during construction are not expected to increase and will not exceed SEPP 33 screening thresholds for storage.
However, some chemicals like paint and fuel and grease will be stored on site for use associated with the construction works. The implementation of standard mitigation measures and compliance with WorkCover and other safety controls will reduce the risk of hazardous chemical events associated with the proposed work, such as:
• storage of fuels and chemicals in accordance with Australian Standards (AS) 1940
• chemicals used for the operation of the OTF will be stored and used in accordance with the requirements of the Dangerous Goods Act 1975 and WorkCover
• machinery, plant and equipment will be inspected for signs of fuel or oil leakage. Leaks identified would be repaired immediately or the equipment will be removed
• a spill kit will be kept onsite at all times
• refuelling or decanting is to take place in a nominated sealed area.
SEPP 33 Guidelines recommend that premises requiring an EPL be considered as a potentially offensive industry. However, the guidelines also state ’in most cases, compliance with the EPA requirements should be sufficient to demonstrate that a Project is not an offensive industry.’ Cronulla WWTP operates and is expected to continue to operate within the requirements of its EPL and is therefore not classed under SEPP 33 as an offensive industry.
Operation
Refurbishment of the existing and the operation of the new OTF, may increase chemical consumption of the biotrickling nutrient solution only. Chemical storage requirements for the operation of the Project will not exceed SEPP 33 screening thresholds for storage. The licensed storage capacity under WorkCover Dangerous Good Licence and EPL No. 1728 will not be exceeded.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 There is the potential for an increase in vehicle movements transporting chemicals to the site during operations. This is anticipated to be minimal and within the SEPP 33 transportation screening thresholds. 5.6.3 Conclusion
A minimal increase in both energy and chemical use is expected when the new OTF is operational. The energy changes will be monitored and recorded as part of Sydney Water’s standard NGER Act reporting program. Energy consumption and chemical use required by the Project are not assessed as causing a significant impact to the environment, given the current levels of use and provided the mitigation measures are implemented. The Project is not classified as potentially hazardous and is unlikely to pose a significant risk to the community or the environment.
5.7 Waste management 5.7.1 Existing environment
Under existing operations at Cronulla WWTP, grit and screenings are either composted at a resource recovery centre or disposed of at landfill. Biosolids are transported off site for use in landscaping. General waste is collected from the WWTP and taken to landfill for disposal.
There are existing waste collection and recycling services at the WWTP. Licensed transporters take hazardous waste generated on the works site for disposal at a DECCW licensed facility. A similar process applies to disposal of existing OTF biological media. 5.7.2 Impacts and environmental measures
Construction Operational wastes generated from the WWTP are not expected to change during the construction of the proposed work. However, construction work at the WWTP will generate construction waste, including:
• a large volume of waste will be generated from the removal of corroded metal (steel and other metals) and concrete from the refurbishment areas. Most of this waste will be recycled, however some materials will potentially not be recyclable due to their poor condition eg metal fatigue or corrosion and contamination. This is not expected to be a significant portion of the total waste volume
• small amounts of building waste, spoil and fill, green waste, and general waste. Existing waste management processes will remain in operation during construction and will continue when the new OTF comes on line. Wastes from construction and demolition will be disposed of in accordance with the WARR hierarchy. Re-use of waste on site is the preferred waste management option and will be carried out if possible.
The following safeguards should be implemented to minimise waste impacts:
• all waste material and disposal activities will be undertaken in accordance with the provisions of the PoEO Act, the WARR Act, Sydney Water’s Waste Minimisation Programs (completion of purchasing and waste audit forms) and the NSW DECCW Waste Classification Guidelines (2008)
• waste streams will be sorted to maximise the recycling potential and minimise disposal costs
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 • materials purchasing should favour products that avoid waste generation
• all waste is to be recycled. If recycling is inappropriate, waste is to be removed to an approved waste disposal depot
• a sufficient number of bins or similar receptacles will be provided for waste disposal on the work site. Separate receptacles will be provided for recyclable materials
• all general garbage from the work sites will be disposed of at the end of each day to reduce the risk of odour, attracting rats or other animals to the work area
• all dockets and receipts for waste disposal are to be kept and copies forwarded to the project manager as proof of disposal and for environmental audit purposes
• contaminated waste is to be removed to a licensed waste disposal depot
• any fuel, lubricant or hydraulic fluid spillages will be collected using absorbent material and the contaminated material disposed of at a licensed waste depot
• all liquid wastes shall be collected and disposed of in accordance with all DECCW and Sydney Water requirements
• there is to be no residual contamination to land at the proposed work sites or at any other area, as a result of the activities carried out.
Operation The Project will result in two new operating waste streams:
• the biomass used in the biofilters, components of individual OCUs
• acid liquor, a bye product of the biofilters. Current waste management processes will be extended to incorporate the biomass waste generated from the proposed works. The biomass will be collected and transferred off site and disposed as per DECCW requirements. The acid liquor will be collected and sent under pressure to the head of works and treated in the WWTP.
During the operation of the OTF waste material and disposal activities will be undertaken in accordance with the existing WWTP waste management processes and procedures. 5.7.3 Conclusion
The impacts of waste generation from the construction and operation of the OTF at Cronulla WWTP will be minor and can be adequately managed provided the measures outlined are implemented. Waste produced onsite will be reused onsite or recycled where possible. Excess spoil and waste, which is unable to be reused or recycled, will be disposed of at an appropriate licensed waste disposal facility.
5.8 Heritage – Aboriginal and non-Aboriginal 5.8.1 Existing environment
The Cronulla WWTP operations area has been extensively disturbed during the construction of the plant. Consequently, it is unlikely that any Indigenous or non-Indigenous relics exist in the location
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 of the proposed work. A search of the following instruments and heritage registers has been undertaken to identify the presence of heritage items in the vicinity of the proposed work:
• Sydney Water S170 Heritage Register
• NSW State Heritage Register
• Sutherland LEP
• Australian Heritage Commission Register of the National Estate (RNE)
• National Trust of Australia
• Australian Heritage Information Management System (AHIMS).
Aboriginal heritage
The Kurnell Peninsula possesses a rich cultural significance for the local Gweagal Aborigines, a clan of the Dharawal tribe, who inhabited the area originally. Aboriginal camp sites and shell middens are known to occur adjacent Captain Cook Drive and Quibray Bay and within the Botany Bay National Park. One site of Aboriginal value, identified as the Towra Point Resting Place at Towra Point nature reserve, is listed on DECCW’s AHIMS database. The Cronulla WWTP site is within the boundaries of the La Perouse Local Aboriginal Land Council.
A number of Aboriginal sites were nominated in the Sutherland Shire LEP but none was located within the WWTP site. However, an Aboriginal midden was discovered approximately two metres below the surface near the northern boundary of the WWTP during excavation for the ocean outfall during the upgrade work completed in 2000. This site is located in the natural area of the WWTP site.
Over the years, the operations area has been significantly disturbed due to site levelling and filling, construction and demolition. No artefacts have been found.
Non-Aboriginal heritage
The Cronulla Sand Dune and Wanda Beach Coastal Landscape are listed on the State Heritage Register.
The Sutherland Shire LEP lists a number of non-Aboriginal sites on the Kurnell Peninsula but none within the WWTP site.
The Cronulla WWTP site is listed under the Sydney Water Section 170 NSW State Agency Heritage Register (Heritage No. 4573705). The WWTP is significant as a feature of the locally developing economy. The major historic themes include health, technology and utilities. However, the site fabric has been modified and new functions added over time, as this is an operating plant. The listing does not preclude changes to the fabric of the infrastructure. Refer to Appendix 2. Heritage for the approval to disturb the site. 5.8.2 Impacts and environmental measures
There are no known heritage or archaeological constraints to the Project. It is unlikely that there are any Aboriginal relics located within the area of the proposed work. Should any unidentified archaeological items be encountered during the construction phase, work in the vicinity would be suspended until a qualified archaeologist has assessed the findings.
The construction of the OTF would not have any significant impact on the listed heritage items, or to any other items of heritage significance in the Kurnell Peninsula. However, if any Aboriginal or non-Aboriginal heritage items are discovered during construction, all work will cease in the area
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 and the Project Manager will inform the Sydney Water Environmental Representative as soon as possible.
The operation of the proposed OTF at the Cronulla WWTP will not affect any non-Aboriginal or non- Aboriginal heritage item. 5.8.3 Conclusion
It is unlikely that any items of heritage significance will be disturbed during the proposed work due to the disturbed nature of the proposed work location. However, strict adherence to mitigation measures identified in Section 5.7.2 will ensure that any impacts on any heritage items as a result of the Project are minimised.
5.9 Traffic and access 5.9.1 Existing environment
Traffic generated by the WWTP is generally stable, with the majority of traffic comprising staff entering and leaving the site for work purposes. The typical current traffic movements are:
• 30 to 40 light vehicle movements (staff, contractors, visitors) per day
• 2 truck movements per day
• 2 truck movements for biosolids removal per week.
Entry to the WWTP site is restricted to authorised personnel by a security gate. Within the operations area there is adequate parking for the staff plus a limited number of visitor vehicles. The operations area can be congested at times and traffic can require management to ensure it flows freely.
Captain Cook Drive provides the only road access to the WWTP site and the Kurnell Peninsula. It regularly carries heavy vehicles to industrial areas. Trucks form a significant proportion of traffic during normal working hours, however residential and commuter traffic comprise the bulk of the traffic. Captain Cook Drive has a single driving lane each way, however the pull-off lanes are generous and can accommodate a parked car. However, no parking is permitted along Captain Cook Drive. Any event that impedes the traffic on Captain Cook Drive can be significant as it is the only access to the Kurnell Peninsula. 5.9.2 Impacts and environmental measures
Construction
The refurbishment of the OTF at Cronulla WWTP would potentially impact traffic and surrounding land uses. In addition to the current vehicle movements, it is estimated that approximately 10 heavy vehicle movements per day may be required during construction at times to bring equipment and materials into and out of the works site.
The number of additional private vehicles for construction workers is estimated to be 10 and 25 (numbers will vary depending on tasks and program). Construction vehicles will be parked within the WWTP.
Internal access and parking will be adequate to accommodate the construction vehicles and equipment required for the proposed project. However the operations area is physically congested and access, especially for large vehicles. Good traffic flow would require careful planning.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 Potential impacts to traffic and access during construction include:
• partial road closures may be required to allow delivery of the four biotrickling tanks to the WWTP. This is expected to occur during the night to reduce traffic impacts
• increased local traffic on Captain Cook Drive potentially leading to traffic delays
• reduced safety for pedestrians and cyclists on Captain Cook Drive due to increased traffic.
The following safeguards would be implemented to minimise local impacts from traffic:
• materials would be delivered during standard working hours avoiding school drop off and pick up hours between 8 am to 9.30 am and 2.30 pm to 4 pm
• prior notification to council will be given if any materials would be delivered after standard working hours
• RTA, SCC and local community to be advised of any changes to traffic and access along Captain Cook Drive
• lane closures are to be limited to the minimum amount of time required to allow for safe traffic movements
• heavy vehicle use on major roads should be timed for periods of lower traffic loads eg out of peak periods and night time
• all works related access and storage should be confined to existing sealed areas unless approved by Sydney Water
• access to existing gates and access tracks within the WWTP must be maintained throughout the project.
Operations
Operating traffic numbers and access conditions are expected to remain similar to current levels. At most, one new truck movement per month will be required to service the OTF. The impact of the new operations on existing traffic is not expected to be significant. 5.9.3 Conclusion
Total vehicle movements generated during the construction period are approximately 40-65 per day. While there could be traffic hold-ups at times, the local community is not expected to experience a significant change in traffic conditions or safety. There will be a negligible increase in vehicle movements during operations.
The safeguards outlined above will ensure that the local traffic flows are not significantly impacted by the proposed work. The local community is unlikely to experience a significant impact to traffic, access or safety.
5.10 Visual 5.10.1 Existing environment
The regional landscape setting for the Cronulla WWTP is the Kurnell Peninsula, Botany Bay and Bate Bay. Its character is shaped by large expanses of water surrounded by low hills covered with bushland and forest with glimpses of residential and other development. The Cronulla and Kurnell
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 Peninsula contain a number of different landscape types, from natural, to residential, industrial, commercial and urban. Land use influences landscape character. The WWTP site itself has a number of character zones, with the main dichotomy being between the hard-edged operations area with its irregular skyline and the green forested natural area with its softly rounded skyline.
The local environment in which the WWTP sits is influenced strongly by its topography. From either water edge the land rises sharply to a strong ridgeline with a maximum height of 45RL on the Peninsula. The operations area contains a number of elements that are visible from a distance. These are the biosolids and administration buildings, the reactors and the digesters. The highest structure on the Cronulla WWTP operations area is the light tower which is 28 m high resulting in RL47. The site topography and vegetation surrounding the WWTP effectively screen most of the other structures within the site from view from Captain Cook Drive as well as areas surrounding Woolooware Bay in Botany Bay.
For details regarding areas with views to the WWT, refer to Jackson Teece Architecture 2011, Cronulla Wastewater Treatment Plant Visual Impact Assessment of Proposed Changes , Sydney Water, Sydney in Appendix 5. 5.10.2 Impacts and environmental measures
Consultants Jackson Teece Architecture (JTA) were engaged by Sydney Water to conduct a visual impact assessment (VIA) of the proposed OTF. The objective of the assessment was to consider potential visual impacts on the surrounding areas and to recommend mitigation measures.
During pre-construction, engineering design objectives have considered technical, environmental and social objectives. One objective was to minimise impacts on local amenity, and design objectives of the new OTF included minimising the height, bulk and shape of the OTF. The design was reconfigured a number of times to reduce the visual impact of the new OTF structure, for example, situated as close as possible to existing facilities to minimise impacts. Furthermore, the base level of the OTF was dropped by 1 m to reduce visual impacts. However site conditions, especially underground services constrained options to minimise visual impacts.
Construction is unlikely to impact views from local residential or recreational sites or similar sensitive areas due to the WWTPs distance from developed areas. However, some minor construction visual impacts may be evident. Construction impacts could include views of scaffolding which are potentially reflective, and vehicles and trucks may occasionally be visible but will be partially screened by on-site vegetation. Visual impacts related to the construction phase will be temporary. Refer to Figure 8.
All works will be contained with the Cronulla WWTP operations site. Installation of the OCUs, some 12 m high, and the discharge stack some 20 m high, will permanently change the visual character of the WWTP. The extent of change will depend on screening, the proximity, angle and height of the viewing point. JTA created a 3D model of the wider site, including Cronulla and parts of the Kurnell peninsula and Botany Bay, to help assess impacts.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011
Figure 8: Diagrammatic 3D view of the proposed works
The classification of the visual impact of the proposed work is dependant on the existing character of the views of the WWTP, and the extent of change from the existing view. The WWTP site is generally viewed as an industrial area, in spite of the surrounding vegetation and landscaping. The potential for visual impacts from the Project is generally low. However, given the height of the OTF, some areas, like Captain Cook Drive and the footpath on Wanda Reserve may have a clearer view of the development. An explanation of the classification of visual impact used to assess the proposed OTF is described in Table 6.
Table 6: Classification of visual impacts (JTA 2010).
Visual Impact Description
High Significant change in existing view affecting an extensive area and causing a complete change in the character of the view, due to the scale of the proposed works and alterations to the landscape setting.
Moderate Noticeable change in existing view. The proposed works may be prominent, but is consistent with the scale of the existing development and does not alter the landscape character greatly.
Low Minor change distinguishable from existing view, but character of view remains similar to the existing.
Negligible Change in view is barely perceivable at most.
The visual impact assessment carried out by JTA was based on infrastructure information provided by Sydney Water coupled with Google Maps and JTA’s on-site photographs.
Views to the south across Woolooware Bay to the WWTP were assessed as negligible due to their distance from the proposed works. However, seven key views to the WWTP were identified and their locations are shown in Figure 9.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011
Figure 9: Location of viewpoints selected by JTA for the assessment
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 The proposed OTF will alter the appearance of the WWTP permanently and will be visible from a variety of locations surrounding the WWTP site. A summary of the visual impacts of the Project from the seven locations listed within the visual catchment of the WWTP is provided in Table 7.
Table 7: Summary of visual impacts (JTA, 2010)
Viewpoint Visual Impact Notes
View 1: from Woolooware Negligible Impact Direct glimpses to the site are only available from limited Road between Ambyne locations on the street and the prominence of the structure Street and Short Street is diminished by the dominance of other elements, trees and shrubs and powerlines within the vista. View 2: from Franklin Negligible Impact The proposed structures would be seen against the Road just South of the vegetated backdrop of the WWTP. The proposed works, Sturt Road Intersection albeit visible from this vantage point, is lower in elevation to the tree-line in the backdrop of the WWTP. View 3: from Berry Street Not Applicable The proposed works is not visible from this vantage point, due to the trees and shrubs that exist along the residential street. However, there may be more prominent views to the WWTP from within the two storey dwellings on this street. View 4: from the corner Low Impact From this vantage point, part of the proposed works, the of Bate Bay Road and 20m Discharge Stack, would be visible beyond the existing Lucas Reserve vegetated backdrop and tree-line. View 5: from Captain Moderate Impact The majority of the 20 m Discharge Stack would be visibly Cook Drive on the exposed above the tree line. The proposed works would be intersection between perceived as a noticeable vertical element that breaches the Cronulla High School and visual horizon. the Proposed Residential development View 6: from the northern Low to Moderate The upper parts of the manifold structure and Discharge edge of Wanda Reserve Impact Stack would be visible above the tree line introducing a large vertical element to the visual horizon. The proposed works would cause a noticeable change in the existing view albeit within an area already disturbed by the existing industrial structures. View 7: from the southern Low Impact The low vantage point at which the viewpoint has been edge of the proposed taken, allows the undulating topography to screen the residential development majority of the proposed works, minimising the structures impact on its surroundings.
The two views assessed as important due to the visual impact from the proposed works, are those viewed from Captain Cook Drive and Wanda Reserve (Figures 10 and 11). The views from Captain Cook Drive include a visibly noticeable vertical stack that breaches the horizon but would be seen for a limited distance only. The view may possibly impact the Cronulla High School and the entry to the proposed residential development.
The view from Wanda Reserve is assessed as low to moderate because works would cause a noticeable change in the existing view albeit within an area already disturbed. The view is considered a good indicator of likely visual impacts on the northern section of Wanda Reserve, the Kurnell Sand Dune and the proposed residential area south of the WWTP.
The view of the WWTP from the corner of Bate Bay Road and Lucas Reserve (View 4) (Figure 12) includes the 20 m stack beyond the tree line. This view is identified as important due to the potential concentration of observers within the proposed residential development area. However, the visual impact itself is assessed as low.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011
Figure 10: View from Captain Cook Drive with the proposed stack (View 5)
Figure 11: View from the northern edge of Wanda Reserve (View 6)
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011
Figure 12: View from Bate Bay Road (View 4)
The height of the stack, an essential requirement for improved air quality, is the primary factor contributing to the increased visibility of the proposed works. The following mitigation measures will reduce the potential impacts of the proposed work:
• the biotrickling tanks should be coated in a non-reflective matt grey-green coating in keeping with the surrounding character
• new structures should be painted with a non-reflective colour which complements the existing colours at the WWTP site
• if a rough texture can be added to the finish of any proposed structure it would further aid in reducing reflectivity
• steel elements generally should be of galvanised finish to avoid rusting
• the removal of existing vegetation should be minimised to ensure that existing screening is not removed. If removal is required, then new planting of adequate size should be provided to reinstate the level of screening provided by those plants
• a vegetative screen should be maintained and improved along the WWTP boundaries on Captain Cook Drive and on the eastern boundary facing Wanda Reserve
• if lighting is essential, down lighting should be installed to minimise light spill affecting residents, fauna or adjacent land users. 5.10.3 Conclusion
The visual assessment identifies largely low to moderate visual impacts as an outcome of the proposed works. The edge of Bate Bay Road (view 4), Captain Cook Drive (view 5) and the northern edge of Wanda Reserve (view 6) are identified as the most important of the affected areas.
Mitigation measures have been identified to reduce the visual impact of the proposed works. However, based on the extent and success of the mitigation measures, the status applicable to the viewpoints surrounding the WWTP may be reduced.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 5.11 Cumulative impact
During construction of the Project, other projects may also be undertaken within the WWTP operations area. Sydney Water will ensure that each project manager is informed of the safeguards and mitigation measures for concurrent projects. The goal is to ensure that all documented safeguards, as noted in this REF, are implemented.
The contribution of the proposed work at Cronulla WWTP to cumulative impacts is considered minimal as works will be restricted to the disturbed WWTP operations area, be short term and will result in long-term benefits to the environment and community. The proposed works will reduce odour discharged into the atmosphere and will ensure compliance with DECCW’s odour requirements.
Consequently no significant cumulative impacts are anticipated as a result of the proposed work.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 6. Environmental management
6.1 Project managers responsibilities
The roles and responsibilities of the project manager start prior to the start of works and continue until the project is completed. Refer to Appendix 4.
6.2 Construction and environmental management
Prior to commencement of the proposed works, the construction contractor will be required to prepare a CEMP in accordance with the DECCW Guideline for the Preparation of Environmental Management Plans 2004 and SWEMS0028.01. It will cover the construction and commissioning phases of the proposed works to the satisfaction of Sydney Water. It will address the goals and objectives identified in Chapter 5 Existing environment, as well as potential impacts and measures for each activity. Sydney Water will review the CEMP prior to start of works to ensure risks are addressed and minimised.
According to SWEMS 0028.01 Construction Environmental Management Plan Template , the CEMP will include, but is not limited to, the following:
Commitment and policy
• contractor environmental management policy
• objectives of the CEMP.
Planning
Consideration of environmental aspects and impacts associated with the work including:
• evaluation of environmental risks, associated risk ranking and planned risk mitigation/management measures
• all undertakings and mitigation measures outlined in this REF and any additional environmental impact assessment undertaken
• items arising from liaison with stakeholders.
Implementation
The CEMP will include:
• a complete site layout
• description of measures to be taken to manage the identified aspects and impacts
• description of environmental responsibilities of the contractor and subcontractors
• assignment of corporate and individual responsibilities for implementing, maintaining and monitoring each environmental requirement
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 • procedures and instructions for implementing, maintaining and/or monitoring each environmental requirement
• administrative and supervisory arrangements, responsibilities and accountabilities (eg supervisory protocols, provision of a site environmental manager, management of subcontractors, training of site staff, submission of regular reports) on the implementation of the CEMP
• methods for measurement, evaluation and review
• monitoring and audit procedures.
The use of standard, proven management methods will be encouraged. During detailed planning and design phase of the proposed works, the Sydney Water Project Manager will consider directing a supplementary environmental impact assessment should the scope of works, the environmental impacts or construction methods described in this document alter significantly.
The construction Odour Management Alliance will provide a sufficient level of resources at the site to ensure effective environmental management throughout the duration of the Contract.
6.3 Operational environmental management
The goal of operational environmental management is legal, including licence, and policy compliance. Sydney Water's Water and Wastewater Impact Management System (WWWIMS) forms part of the compliance framework. It addresses ISO14001 and ISO 9001 and AS/NZS 4801 requirements and includes SWEMS.
Sydney Water will review and may amend its existing WWWIMS to incorporate the changes to the WWTP infrastructure and processes as a result of the proposed works. These will include:
• site incident procedures
• chemical storage and handling procedures
• WorkCover licence
• unit process guidelines
• standard safety procedures
• standard operating procedures at the WWTP.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011
7. Conclusion
General
When the WWTP Odour Management Project is implemented, its objectives will be satisfied. They are to:
• significantly reduce the risk of odours impacting on the surrounding community
• achieve the DECCW ‘no nuisance’ odour criteria of 2 OU, 99% of the time during plant operation
• improve the reliability and extend the economic life of the existing infrastructure.
CALPUFF modelling of the Project indicates that the new installation will achieve the DECCW ‘no nuisance’ criteria, of no more than 2 OU, 99% of the time of a one second nose response at the nearest sensitive receptor located on the rezoned land at Wanda Reserve adjacent to the WWTP.
Planning process
The Project will be carried out in the Sutherland Shire LGA. However, the site is subject to State Environmental Planning Policy (Kurnell Peninsula) 1989 and State Environmental Planning Policy (Infrastructure) 2007 which allow Sydney Water to undertake development without consent of Sutherland Council.
The Project was therefore assessed and determined under Part 5 of the EP&A Act with Sydney Water as the determining authority. This REF has been prepared to consider the environmental impacts of the project.
Environmental impacts
The proposed construction and operation of the OTF have a potential to impact on the surrounding environment. Potential impacts include traffic and noise during construction and visual amenity.
The proposed work will result in an improvement to the performance of the OTF at the Cronulla WWTP . It will reduce odours, and potentially reduce odour complaints from residents surrounding the WWTP site. The proposed work will not result in degradation to the quality of the environment, and will not pose a risk to the safety of the environment
Given the implementation of the measures outlined in this REF, the proposed work will not have a significant adverse impact on the environment due to the nature of the work and the limited nature of the operations area.
Therefore, an EIS or further environmental assessment is not required for this proposed work.
Environmental management
The Odour Management Alliance will be required to develop an EMP for the construction and commissioning phases of the project, which will incorporate the mitigation measures outlined in this REF to safeguard the environment during construction and commissioning. The existing WWTP operational management system will be updated to incorporate the operational and maintenance procedures for the new facilities prior to project commissioning.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 The REF concludes that an EIS is not required due to the nature of the work and the limited potential for environmental impact.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 8. References
Jackson Teece Architecture 2010, Malabar Sewage Treatment Plant: Visual Impact Assessment of Proposed Changes, Sydney Water, Sydney.
Jackson Teece Architecture 2011, Cronulla Wastewater Treatment Plan Visual Impact Assessment of Proposed Changes , Sydney Water, Sydney.
NSW Department of Environment and Climate Change and Water1994, Environmental Noise Control Manual, 1994 , NSW Department of Environment and Climate Change and Water, Sydney.
NSW Department of Environment and Climate Change and Water 1999, Environmental Criteria for Road Traffic Noise , NSW Department of Environment and Climate Change and Water, Sydney.
NSW Department of Environment and Climate Change and Water 2000, NSW Industrial Noise Policy, NSW Department of Environment and Climate Change and Water, Sydney
NSW Department of Land and Water Conservation 2004, Urban Erosion and Sediment Control Manual, NSW Department of Environment and Climate Change and Water, Sydney
NSW Department of Environment, Climate Change and Water 2008, Waste Classification Guidelines , Department of Environment, Climate Change and Water, Sydney.
NSW Department of Environment, Climate Change and Water 2009, Interim Construction Noise Guideline, NSW Department of Environment and Climate Change and Water, Sydney.
NSW Department of Environment, Climate Change and Water 2010, Environmental Protection Licence Number 1728 , Sydney Water Corporation, Sydney.
NSW Department of Planning 2006, Protecting our Coast The Comprehensive Coastal Assessment Tool Kit, NSW Government, Sydney.
NSW Department of Planning 2008, Applying SEPP 33, NSW Department of Planning, Sydney.
Sydney Water 1996, Cronulla Sewage Treatment Plant Upgrade: Environmental Impact Statement, Sydney Water, Sydney.
Sydney Water 2004, Cronulla Sewage Treatment Plan Operations Environmental Plan, Sydney Water, Sydney Water, Sydney.
Sydney Water 2008, Sydney Water Customer Complaint Policy and Procedure , Sydney Water, Sydney.
Sydney Water 2008, Sydney Water Sewage Treatment Plan Odour Management Strategy , Sydney Water, Sydney.
Sydney Water 2009, Cronulla Odour Abatement Options Assessment using Multi Criteria Analysis, Sydney Water, Sydney.
Sydney Water 2009, Cronulla Sewage Treatment Plant ST0010 MS000112 Property Environmental Management Plan , Sydney Water, Sydney.
Sydney Water 2009, Cronulla STP Odour Abatement Project Concept Design Report , CH2MHILL, Sydney Water, Sydney.
Sydney Water 1996, Species Impact Statement for Proposed Upgrade of the Cronulla Sewage Treatment Plant, AMBS, Sydney Water, Sydney
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 Appendices
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 Appendix 1 Is an EIS required?
As part of its due diligence requirements under the EP&A Regulation 2000, Sydney Water undertook the ‘Is an EIS required?’ assessment. It addressed factors, specified in clause 228 of the Regulation, to be taken into account when considering the likely impact of an activity on the environment.
The environmental evaluation criteria are listed below. Significance relates to the nature and extent of impacts and the level of impact on environmentally sensitive areas.
Clause 228 summary
In the context of regulation 228 of the Regulation, consideration of the likely impact on the environment of proposed work is summarised below.
Clause 228 factor REF finding
Any environmental impact on a Impacts such as noise from traffic movement, dust and other community disturbances from construction activities may temporarily affect the local community. These impacts would, however, be minor and limited to the work period. In addition, with the implementation of the safeguards identified in the REF and the preparation of a CEMP, the environmental impacts on communities would be minimised. The visual impact associated with the works will be permanent however the impact has been assessed as negligible to low for five sites and moderate and low to moderate for two other sites. This impact is expected to be reduced through mitigation works.
A transformation of a locality The locality will not be transformed by the Project as the work will take place adjacent to existing infrastructure and within a highly disturbed operational area of the WWTP. The implementation of measures outlined in the REF will ensure that environmental impacts will not be significant.
Any environmental impact on the While two EEC are found within the Cronulla site, they are not found ecosystem of the locality within the operations area. The activities generated by the Project are unlikely to impact the local ecosystem as impacts will be confined to the operations area. The operations area is fenced, generally devoid of suitable fauna habitat and the ecosystem is impoverished. Impacts from the Project are not expected to extend beyond the operations area. The implementation of mitigations measures outlined in the REF will prevent impacts on local ecosystems. A reduction of the aesthetic, The management of odourous emissions will greatly improve air quality. recreational, scientific or other The Project will not result in any significant visual impact. environmental quality or value of the Implementation of mitigation measures outlined in the REF would locality ensure aesthetic, recreational, scientific or other environmental quality or value of the locality are not diminished.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 Clause 228 factor REF finding
Any effect upon a locality, place or building The Project will not result in a significant effect on a locality, place having aesthetic, anthropological, or building having aesthetic, anthropological, archaeological, archaeological, architectural, cultural, architectural, cultural, historical, scientific or social significance or historical, scientific or social significance any other special value for present or future generations. or any other special value for present or future generations Any impact on the habitat of any protected Two EEC and six listed fauna, including the Green and Golden Bell or endangered fauna (within the meaning of Frog (GGBF) are potentially found on the WWTP site. The GGBF Section 98 of the National Parks and were known to inhabit the operations area, though they have not Wildlife Act 1974) been for approx two years. Trimming and/ or clearing of some planted trees may be required to improve site access. However, the stand of trees is not a known habitat and cleared trees will be replaced after works are completed. Construction and operations management will include safeguards to ensure the Project will ensure there is no impact on habitat or on protected or endangered fauna. Any endangering of any species of animal Given the small construction footprint, a highly disturbed site and or plant or other form of life, whether living the REF mitigation measures, the Project is not likely to endanger on land, in water or in the air any species of animal, plant or other form of life on land or water or in the air. Any long-term effects on the environment The work will result in positive long-term benefits to amenity levels by improving air quality and odour performance of the WWTP. There will be no adverse long-term effects on the environment. Any degradation of the quality of the Construction will be confined to the operations area which is environment already degraded consistent with long–standing industrial use. Implementation of REF mitigation measures will ensure degradation of adjacent areas is prevented. The Project is not likely to degrade the quality of the environment. Any risk to the safety of the environment The mitigation measures listed in this document serve to minimise risk to the safety of the environment. Any reduction in the range of beneficial Construction or operational activities associated with the Project uses of the environment are not expected to reduce the range of beneficial uses of the environment because activities will be confined to the operations area. No impact on the adjacent natural area is anticipated. Any pollution of the environment The operation of the OTF will impact the air quality by reducing the risk of odours from the OFT to areas surrounding the WWTP. Operation of the OTF will increase tertiary treated effluent discharge through the deep ocean outfall by approximately 0.56%. Discharges to the ocean will comply with licence requirements and the impact on ocean water quality is not expected to be significant. Mitigation measures and safeguards outlined in this REF and the CEMP would prevent any impacts on the environment.
Clause 228 factor REF finding
Any environmental problems associated Waste generation will be managed as per the WWAR Act. For with the disposal of waste example, waste will be recycled where possible. Spoil will be reused on site. Waste not suitable for reuse on site will be tested for contamination and disposed of at an appropriately licensed waste management facility if necessary. Waste generation and its disposal will be reported to Sydney Water regularly.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 Any increased demands on resources There will be an increase in electricity and chemical usage at the (natural or otherwise) that are, or are likely WWTP arising from the construction and operation of the Project. to become, in short supply However, this increase is not likely to be significant. None of the chemicals is likely to be in short supply. Energy needs are supplemented by the co-generation plant on site. Any cumulative environmental effect with No significant cumulative impacts are anticipated to occur as a other existing or likely future activities result of the proposed work.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 Appendix 2 Heritage Impact Management
Cronulla Wastewater Treatment Plant Odour Management Project
Non-Indigenous Heritage – Approval To Develop
Purpose of this Report
The purpose of this report is to:
• obtain approval for the Cronulla Wastewater Treatment Plant (WWTP) Odour Control Project from the SW Heritage Officer.
The associated tasks are to:
• describe the history of the Cronulla WWTP
• describe the heritage status of the site
• identify potential constraints placed on the works by heritage values
• describe the proposed works
• identify potential impacts on the heritage values by the proposed works
• identify management strategies and controls
• provide a photographic record of the affected part of the site.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011
Figure 1: Cronulla Wastewater Treatment Plant Background
The Cronulla WWTP is located on Captain Cook Drive on the Kurnell peninsula. The site is situated on Botany Bay and views to the Tasman Sea to the south. The WWTP is surrounded by native bushland, however the peninsula contains a mixture of recreational, and residential and industrial development. Adjacent land to the south of the WWTP has recently been rezoned for residential purposes. Other residential areas lie to the north along the Botany Bay fringe.
The WWTP catchment extends from Kurnell and Cronulla in the east to Illawong, Sutherland and Heathcote in the west. The catchment boundaries are generally the Georges River to the north, Mill Creek to the west and Port Hacking to the south. The catchment covers an area of approximately 120 km² and is,223,000 people.
Cronulla WWTP, which has an average dry weather flow (ADWF) of 54 ML/D, originally provided primary treatment but by April 2001 the treatment level was upgraded to tertiary treatment. The treated effluent is discharged through a rising main 5.2 km away from the plant to a shoreline outfall at Potter point on the south side of the Kurnell Peninsula. The outfall discharges approximately 6 m below the surface.
Sydney Water proposes to install an odour control facility at Cronulla Sewage Treatment Plant (WWTP) to comply with the 2 Odour Units (OU) DECCW odour performance criteria which can be summed up as the ‘no nuisance’ criteria.
Heritage Status
The Cronulla WWTP is listed on the Sydney Water Heritage Register in accordance with the Heritage Act 1997 s170 . The site meets the following State Heritage Register criteria: a) Historical: significant as the fourth largest sewage treatment plant with an ocean outfall ‘built to service the growing population of Sydney during the twentieth century. ’
The Cronulla WWTP contains ‘ remnant structures from its first generation of operating
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 technology which have been incorporated into the current phase of operations, particularly the former Digester tanks and the former Pump House .’ b) N/A c) Aesthetic : the WWTP contains ‘ a collection of processes and technologies which together represent the most developed form of primary sewage treatment utilising shallow ocean outfalls currently in use in Sydney ’ d) Social: N/A e) Research : the Cronulla WWTP utilises ‘ a set of processes and technologies which provide…. opportunities for investigation of sewage composition, treatment and reticulation in a local context ’ f) Rarity : ‘ The Cronulla Sewage Treatment Plant is the only Sewage Treatment Plant operating for the Cronulla-Sutherland area and is one of four ocean-outfall treatment plants serving the greater Sydney Metropolitan area and is the only one of these four still utilising a shallow ocean outfall ’ g) Representative : The Cronulla WWTP is a ‘ typical Sewage Treatment Plant ’ h) Inte grity Assessment : The Cronulla WWTP is a complete ‘ operating plant .’ ‘ It has some historic fabric which has been modified and adapted to new functions .’ Refer to the Sydney Water Heritage Register s170 Cronulla WWTP for more details.
Potential constraints on development due to heritage values
The Cronulla WWTP is listed as a heritage item because of its significance as a public utility servicing the Cronulla-Sutherland area of Sydney, and as one of the four major treatment plants serving the greater metropolitan area. The WWTP has historic and social values relating to its function and contains a set of equipment and structures that are representative of their period and type.
The proposed changes are not inconsistent with the Heritage Listing.
Proposed work at the Cronulla WWTP
The odour abatement strategy for Cronulla WWTP consists of controlling odour from major odour sources that are currently uncovered or unventilated, and addressing the identified shortcomings of the existing odour control facilities.
Based on the results of odour modelling, site inspections and operator feedback, the odour abatement strategy for Cronulla WWTP will comprise of the following works:
• covering the primary sedimentation tanks and inlet channel with low profile covers to control odours and ventilation of foul air
• simplifying the current scum collection system using a spray system for scum conveyance
• capturing and treating foul air from the grit handling facilities
• replacing existing ductwork and improving ventilation in the existing covered primary processes
• installing a new biotrickling filter to treat the foul air extracted.
Potential Impacts of the Proposed Works on Heritage Values Given that the Cronulla WWTP is heritage listed for its technology and its history of wastwater service within the community, these changes can be viewed as an extension of the on-going practice of upgrading of the site.
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 Remnant structures on the site, have been incorporated into the current phase of operations. The proposed biotrickling filter system work will be constructed in an already cleared/concreted section of the WWTP site. Therefore, remnant structures will not be impacted by the proposed work.
Impact Management Strategies
Given the heritage values identified in the Heritage Listing, no heritage impact strategies are required for the Cronulla WWTP REF or for the associated contract.
However, the following safeguards will be implemented as part of the REF and the Contractor Construction Environmental Management Plan, to minimise potential impacts to heritage:
• training of construction contractors and subcontractors
• implementation of all relevant legislative and SW procedures if an item (or suspected item) of Indigenous or non-Indigenous heritage is discovered during works.
Approval Recommendation
This report is received and noted and approval is hereby given for the proposed work to proceed as specified.
Jacqui Goddard Signed:
Jacqui Goddard Program Leader Name: Heritage
Date: 17 February 2011
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 Appendix 3 Photos
Cronulla Wastewater Treatment Plant Odour Management Project
Proposed Work
The following photographs show the Cronulla Wastewater Treatment Plant site and surrounds, and general arrangement as of October 2010.
The figures were provided in the Cronulla WWTP Odour Abatement Project: Concept Design Report (September 2010). These figures identify areas and items that will be addressed in the Project .
Figure 1: Proposed covers for the PSTs
Figure 2: Scum collection system water sprays
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011
Figure 3: Corroded steelworks to be replaced
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 Appendix 4 Project Managers Responsibilities
Before commencement of the proposed work, the Project Manager will: ••• ensure that the environmental measures identified in Section 5 of this REF are incorporated as Special Conditions of Contract in any contract or work specification ••• ensure that an Environmental Management Plan (EMP) is prepared and approved prior to work commencing. The minimum requirements that will be met for the preparation of the EMP are those set out within the SWEMS0026 Preparation of an EMP Procedure ••• undertake a supplementary environmental impact assessment should the scope of work or construction methods described in this document alter significantly ••• consult with the Customer and Community Relations Representative regarding the development of a Community (Liaison Plan).
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011 Appendix 5 Visual Impact Assessment
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Cronulla Wastewater Treatment Plant Odour Management Project - April 2011