Public Works Committee: Bolivar Wastewater Treatment Plant Biosolids Storage Capacity Upgrades

Ms HOOD (Adelaide) (11:54): I move:

That the 148^th report of the committee, entitled Bolivar Wastewater Treatment Plant Biosolids Storage Capacity Upgrades, be noted.

The proposed works at the Bolivar Wastewater Treatment Plant will address required improvements to Bolivar sludge and biosolids management, including resolving capacity risk due to peak wet weather events and catchment growth. The treatment plant is the largest wastewater treatment plant in the Adelaide region and processes almost 70 per cent of Adelaide's metropolitan wastewater. The solid material that is separated from raw sewage in the wastewater treatment process is referred to as sludge. Additional sludge from locations across the state is transported to the Bolivar site, where hardstand space is used to convert it into a biosolid product via agitated air drying.

Stockpile space is available at the site to store the product until farmers collect it to use as fertiliser, providing a low-cost and environmentally sustainable way for SA Water to dispose of sludge that also benefits the state's farmers. A sludge management review has determined that additional hardstand and stockpile capacity will be required to cater for future growth in the sludge treatment over the next 15 years. Increasing biosolids storage areas will ensure SA Water is able to dispose of sludge ethically and responsibly without the need to consider landfill or other alternative disposal methods.

Option analysis during project planning determined that an additional stockpile area is best achieved by expanding into a new site location at Bolivar, and the additional hardstand area is best achieved by converting existing temporary stockpile and hardstand areas into permanent hardstand storage. The works will also include the construction of necessary supporting infrastructure.

Five different locations were shortlisted for the additional stockpile area, and the preferred 4.2 hectares was selected based upon a multicriteria analysis and evaluation of net present value. The project will also provide a new hardstand area of 3.9 hectares through the conversion of existing temporary hardstand and stockpile areas. The works will also include:

the erection of fencing and screening around the new stockpile area;

construction of a new drainage pump station to account for discharge into existing stormwater swale;

construction of an access road around the new stockpile area and pump station;

construction of a new weighbridge facility, with an associated operations building; and

construction of a new potable water supply as well as wastewater drainage from the new operations building.

Works are expected to commence this quarter with the anticipation to be complete by early 2027. The agency does not expect the works to disrupt existing operations. The project is expected to cost $22.2 million, with ongoing operational costs of approximately $3.3 million over a 30-year period. Funds are available for the project within the capital budget submitted by SA Water to the Essential Services Commission of South Australia for the 2024 regulatory determination budget and therefore have no impact on SA Water's overall borrowing or contributions to government.

SA Water has included the delivery of the project within the agency's wastewater major framework program, and procurement has been conducted in accordance with SA Water's policies and procedures and conforms to all applicable Treasury and government policies.

The agency uses procurement frameworks that enable the sequential award of work, incentivising suppliers to perform well to ensure continuity of work. The agency states that this delivers significant efficiency benefits through collaboration, innovation, consistency planning and programming. In June last year, SA Water extended major framework partner agreements. Award of the design and construct package shall be in accordance with SA Water's delegation of financial and procurement authority and applicable Treasury and government policies.

The project is being managed in accordance with SA Water's corporate project management methodology by a project manager from the agency's capital planning and delivery group. The project manager is responsible for the development and delivery of the overall project, including seeking the necessary approvals and management of a selected contractor.

SA Water has a business management policy and framework that is used to identify risks, determine related impacts and develop mitigation strategies. Potential risks include appropriate disposal of biosolids to landfill as well as construction impacts, including clearance of native vegetation. Design and construction risk evaluation will continue over the course of the project.

SA Water's corporate-wide policies reinforce its commitment to operating sustainably to support viability now and into the future. The selected contractor will be encouraged to develop processes with due regard for short and long-term local and global environmental, social and economic considerations. This includes conservation and efficient use of resources and raw materials, engaging local subcontractors where expertise is available, reducing carbon emissions, developing flexible processes and products, and implementing recycling and reuse to reduce waste.

An environmental control plan has been prepared to ensure the project is delivered in compliance with relevant regulations, and the selected contractor will be required to establish a construction environmental management plan outlining the general environmental controls and mitigation measures that will be implemented during project delivery. A site environmental plan will also be developed to address site-specific environmental management requirements and associated approval conditions. SA Water will monitor the execution of both plans throughout site inspections and audits.

The project has been assessed by SA Water's Aboriginal heritage adviser, who has identified an elevated risk of impacting or encountering Aboriginal heritage. The design and construct contractor will be required to comply with SA Water's standard operating procedure for the discovery of Aboriginal heritage during construction work.

Debate adjourned.