Western Sydney Recycled Water Initiative – Replacement Flows Project, Sydney, Australia

The Western Sydney Recycled Water Initiative – Replacement Flows Project is a key component of the New South Wales State Government's Metropolitan Water Plan. It is part of a long-term strategy to increase the amount of wastewater being re-used for beneficial purposes.The project is designed to save drinking water and maintain the health of the Hawkesbury-Nepean River system west of Sydney. This is achieved by augmenting water currently released from Warragamba Dam to maintain riparian and environmental flows.The scheme will produce up to 18,500 ML per annum of highly treated recycled water. It involves pumping tertiary treated effluent from three existing Water Recycling Plant's (WRP) to a newly constructed Advanced Water Treatment Plant (AWTP). Here it undergoes a number of treatment processes including ultrafiltration and reverse osmosis.The highly recycled water is then pumped to Penrith for discharge into the Hawkesbury-Nepean River, while waste streams are returned to Sydney Water's wastewater system for retreatment. The scheme is also designed to be flexible enough in operational capacity to accommodate existing and future recycled water customer's needs in the growing Western Sydney areas as well as downstream water irrigators in the Hawkesbury-Nepean River basin.The project was delivered under a Design and Construction (D&C) contract with Deerubbin WaterFutures, a consortium consisting of United Group Infrastructure, McConnell Dowell Constructors (Australia) and GE Water and Process Technologies. Deerubbin WaterFutures will also operate and maintain the new plant under a 10-year contract.The complexity of the scheme was greatly influenced by new technology, the multiple interfaces with existing Sydney Water's Water Recycling and Wastewater Treatment Plants and the scale of the scheme. The project delivery team adopted an integrated team approach. This approach maintained a continual focal point on both project delivery objectives and the future operations and maintenance needs throughout the design and construction phase.This paper presents an overview of the scheme and an operational perspective on some of the key challenges faced in delivering this scheme through design and construction and into the operations phase.