Securing water supplies in WA

Representing the first public private partnership (PPP) for the West Australian water industry, the $300 million Mundaring Water Treatment Plant is designed to provide a secure and exclusive source of potable water for around 100,000 rural and town services in West Australia’s Wheatbelt and Goldfields regions.

The project is the latest and largest upgrade to the iconic Goldfields and Agricultural Water Supply Scheme which has been operating since 1904. The PPP model was adopted to maximise technical input from the private sector while providing the owner with a commercially competitive capital and operational cost. It is a first-class example of what can be achieved when a large number of parties providing different services are brought together for a single purpose.

Funded and built on behalf of the Water Corporation of WA by the Helena Water consortium, the design and construction of the plant was wholly funded by private-sector finance. ATJV (a joint venture company owned equally by ACCIONA Agua and TRILITY) and GHD were the designers for the project, with ATJV and Brookfield Multiplex responsible for all construction and commissioning activities.

Located on an historic, redeveloped 13.6 hectare site near Mundaring Weir, 30 km east of Perth, the project comprises a fully commissioned 165 ML/day (expandable to 240 ML/day) water treatment plant and pump station.

Reliable and consistent delivery of water to the right quality and of the right volume is at the very heart of this project. The contract requires that the drinking water produced meets specific parameters at five different stages of the treatment process, which is monitored using 14 online parameters, via 65 separate automatic online sample measurements.

At all stages, the implementation team was independently challenged on whether delivery could be better achieved using more sustainable design or techniques. This process ensured the project was delivered using innovation and the latest technology in the most sustainable way possible. As an example, the equipment selection process included whole-of-life cost analysis to ensure the longevity of the asset life, whilst realising energy consumption efficiencies.

During construction, re-use of existing pipelines was incorporated wherever possible. To enable this to take place without compromising reliability of water delivery, an extensive existing pipeline condition assessment was undertaken. Construction of a water-treatment plant on five separate levels on the side of a steep hill inherently comes with its safety challenges. All foreseeable issues were addressed via construction management plans which were strictly enforced. Where unforeseeable circumstances were encountered these were quickly identified, assessed and new procedures adopted to eliminate safety risks.

The project objectives have been surpassed and the facility and integration work was constructed and commissioned in around two years. The project has also achieved all its stakeholder key objectives, and in many areas surpassed expectations.

Liaison and involvement of the local community at all stages of the project was and remains essential. The effectiveness of meeting this objective was assessed via regular meetings with the community representative group, at which feedback was encouraged.

Officially opened in March 2014, ATJV will now operate and maintain the plant and pump station for 35 years.