Decision Report
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Decision report North Head Wastewater Treatment Plant NSOOS Scrubber Replacement Project March 2014 Sydney Water - Commercial in Confidence Page | 1 © Sydney Water Corporation (2014) Commercial-in-Confidence. All rights reserved. No part of this document may be reproduced without the express permission of Sydney Water. File Reference: S:\\Sustainability\EP&M\WASTEWATER\North Head\Replacing the NSOOS Scrubber\140307_NSOOS Scrubber Replacement Decision report.docx Publication number SW199 3/14 Sydney Water - Commercial in Confidence Page | 2 Contents 1 Introduction 5 1.1 Purpose of the Decision report 5 1.2 Planning approval framework 6 1.3 Summary of the proposal from the REF 7 2 Consultation 8 2.1 Proposal development and REF preparation 8 2.2 Public exhibition of the REF 8 2.3 Submissions 9 2.4 Further consultation 9 3 Changes to the proposal 10 3.1 Amendment to REF contours 10 4 Summary of issues raised 11 5 Consideration of issues 13 5.1 Air quality (odour) 13 5.1.1 Objectives of proposal and odour performance 13 5.1.2 Efficiency of new scrubber 15 5.1.3 Scope of odour work 17 5.1.4 EPA guidelines and licensing 20 5.1.5 Managing odour at North Head WWTP 23 5.1.6 Effect of odours from North Head WWTP 25 5.2 Alternatives considered 26 5.2.1 Selection process 26 5.2.2 Design considerations 28 5.3 Community and stakeholder engagement 29 5.3.1 Consultation process for the proposal 29 5.3.2 Sydney Water complaints process 31 5.3.3 Decision report queries 32 5.4 Environmental management 32 5.4.1 Environmental performance and management of North Head WWTP 32 5.4.2 Construction environmental management 34 5.4.3 Flora and fauna 35 5.4.4 Waste management 35 5.4.5 Heritage 36 5.4.6 Traffic and chemical use 37 5.5 Scope of assessment, technical clarifications and corrections 38 5.5.1 Scope of assessment in the REF 38 Sydney Water - Commercial in Confidence Page | 3 5.5.2 Technical clarifications 40 5.5.3 Corrections 41 5.6 Support for the proposal 41 6 Justification of the proposal 42 7 Conclusion 43 8 Recommendation 44 9 References 45 Figures Figure 1 Location of North Head WWTP (ESRI, 2013) 6 Figure 2 Artist’s impression of the NSOOS Scrubber Replacement Project 7 Figure 3 Predicted 2 odour unit contours with estimated (REF) and measured air flows 10 Figure 4 Predicted 2 odour unit contours for 1,000 and 500 odour units at outlet 17 Tables Table 1 Issues raised in submissions 11 Table 2 Comparison of different odour concentration data and air flows for the NSOOS scrubber 15 Table 3 Upcoming projects which may influence odour from North Head WWTP 18 Table 4 Odour assessment criteria (EPA, 2006) 21 Table 5 Summary of potential impacts during operation of the proposal 38 Appendices 1 Community and stakeholder engagement 2 Submissions 3 Additional environmental measures Sydney Water - Commercial in Confidence Page | 4 1 Introduction The North Head Wastewater Treatment Plant (WWTP) is located on Blue Fish Drive, North Head, in the Manly local government area. The WWTP is situated on the eastern side of North Head peninsula, which also includes the North Head Sanctuary (former School of Artillery), the Australian Institute of Police, Manly Hospital and St Pauls College. Sydney Harbour National Park borders the WWTP to the south and north, with the Tasman Sea to the east and north east (Figure 1). North Head WWTP is the second largest wastewater treatment plant in Sydney, providing high rate primary wastewater treatment and operating 24 hours a day, seven days a week. Chemical scrubbers are used at North Head WWTP to control odours associated with the transfer and treatment of wastewater. The scrubbers treat ‘foul air’, before discharging the air to atmosphere. The Northern Suburbs Ocean Outfall Sewer (NSOOS) scrubber is approaching the end of its useful life and needs to be replaced. Sydney Water and the Odour Management Program Alliance (the Alliance) propose this North Head NSOOS Scrubber Replacement Project to improve the reliability of the WWTP and help reduce corrosion in the NSOOS. The proposed works include: replacing the existing chemical scrubber with a bio-trickling filter (BTF) scrubber, made up of nine units and associated infrastructure including duct work, a ventilation stack and water tank modifying the underground ventilation system at the plant decommissioning and removing the existing NSOOS chemical scrubber, once the bio-trickling filters are operational completing associated infrastructure works, including work on internal roads. We do not expect the proposal to cause any significant environmental or community impacts, once it is operational. The proposal should slightly improve odour impacts on the surrounding community. Sydney Water and the Alliance completed a Review of Environmental Factors (REF) for the proposal in October 2013. We placed the REF on public display from 28 October to 11 November 2013 and invited community members and other interested stakeholders to comment on the proposal in the REF. Sydney Water received 20 submissions, following the public exhibition of the REF. These raised issues related mainly to air quality and odour, the scope of the proposal, alternatives considered and environmental management during construction. We have not significantly changed the proposal since public exhibition of the REF. However, we have included several new mitigation measures to address some of the issues raised in submissions. This Decision report addresses issues raised in the submissions. 1.1 Purpose of the Decision report This Decision report: considers the issues raised in submissions identifies and assesses whether the submissions require any changes to the proposal identifies whether the submissions require any new mitigation measures, or changes to existing mitigation measures recommends whether Sydney Water should proceed with the proposal. Sydney Water - Commercial in Confidence Page | 5 Figure 1 Location of North Head WWTP (ESRI, 2013) 1.2 Planning approval framework The Environmental Planning and Assessment Act 1979 (EP&A Act) provides the statutory context for the proposal’s environmental assessment. We are assessing and determining the proposed work under Part 5 of the EP&A Act, with Sydney Water the determining authority. The State Environmental Planning Policy (Infrastructure) 2007 allows Sydney Water to complete the work without development consent from Manly Council. The REF assessed the potential environmental impacts associated with replacing the NSOOS scrubber and associated infrastructure. We considered potential impacts against the matters listed in clause 228 of the Environmental Planning and Assessment Regulation 2000 (EP&A Regulation). Our assessment concluded that it is unlikely that the proposal will have a significant impact on the environment. We have not changed this conclusion after considering the submissions, so an environmental impact statement is not required. Sydney Water - Commercial in Confidence Page | 6 1.3 Summary of the proposal from the REF The North Head NSOOS Scrubber Replacement Project (the ‘proposal’) involves: replacing the existing NSOOS chemical scrubber with a new bio-trickling filter (BTF) scrubber which will be more reliable. The scrubber includes nine BTF units and associated water tank, pipe and duct work and a ventilation stack modifying the underground ventilation system decommissioning and removing the existing NSOOS chemical scrubber installing associated infrastructure and services, and work on internal roads. We will be completing work both above and below ground. Figure 2 shows the layout of the proposal. Vent stack BTF towers Pipe and ducting work Water tank Figure 2 Artist’s impression of the NSOOS Scrubber Replacement Project Sydney Water - Commercial in Confidence Page | 7 2 Consultation Sydney Water developed a communication strategy to ensure the local community and key stakeholders are given clear, accurate and timely information during the proposal’s various stages. We identified key stakeholders according to their interests of the proposal’s potential impacts. As part of the communication strategy, we consulted with the local community and key stakeholders while preparing and exhibiting the REF. This includes preparing and displaying the REF, considering submissions and preparing this Decision report. Appendix 1 includes examples of the consultation completed for this proposal. The following sections describe the consultation to date. We will continue to inform the community and key stakeholders about the proposal. 2.1 Proposal development and REF preparation While preparing the REF and developing the proposal, we: wrote to key stakeholders, in July 2013, seeking input for the REF presented information about the proposal with key stakeholders before the REF public display, including: - North Head WWTP Community Consultative Committee (CCC), on 14 August 2013 - Manly Council Community Environment Committee, on 11 September 2013 - North Head Sanctuary Foundation, on 12 September 2013. set up a community information line, website, and email address. 2.2 Public exhibition of the REF The REF was on public exhibition from 28 October to 11 November 2013 at: Manly Council, Customer Service Centre, 1 Belgrave Street, Manly Manly Library, Market Place, Manly Manly Environment Centre, 41 Belgrave Street, Manly Sydney Water invited the community and stakeholders to provide comments or submissions on the proposal. The deadline for REF submissions was initially 15 November 2013, however we extended this to Friday 22 November 2013 to meet requests from a number of submitters. During exhibition of the REF, we consulted with the community and stakeholders and invited comments and submissions by: advertising the REF in the Manly Daily on 26 October 2013 (a copy of the newspaper advertisement is attached in Appendix 1) holding a drop-in information session at Manly Community Centre on 4 November 2013 from 4 pm to 6 pm. At the session, we provided information including printed and CD copies of the REF, photographs and images of the plant and the proposal, and a fact sheet summarising the project.