Future-proofing Sydney's water supply through partnership and innovation

Serving around 85% of Sydney’s population, approximately 5.4 million people, the Prospect Water Filtration Plant ranks among the largest facilities of its kind globally. As the city expands, that figure is expected to grow to nearly 8 million over the next 25 years.

At the same time, ageing infrastructure and intensifying weather patterns are placing Sydney’s water system under increasing pressure, heightening the challenge of maintaining water quality and securing a reliable long-term supply.

A textbook example of partnership and collaboration

Addressing these challenges required more than upgrading existing equipment. The solution was the development of a brand new pre-treatment super facility at Prospect, designed to enhance system resilience for generations to come.

Valued at €199 million, the project is being delivered by infrastructure specialists SUEZ and Acciona, with Alfa Laval supplying four world-leading Alfa Laval decanter centrifuges.

The initiative is the latest chapter in a long-standing collaboration between the four organizations, each contributing specialist expertise throughout the design, testing and delivery phases.

Validating performance under real-world conditions

For Alfa Laval Australia, the project began long before construction. While the existing plant had operated reliably for more than 25 years using decanter centrifuges, changing conditions and higher operational demands required a new approach.

The Prospect Water Filtration Plant has done an outstanding job supplying quality drinking water for decades," explains an Alfa Laval Australia representative. "But like any major infrastructure, equipment ages and operational challenges begin to emerge, particularly during periods of high demand."

Rather than upgrading the existing equipment, discussions between the project partners concluded that a completely new pre-treatment facility would provide the most resilient long-term solution.

Working closely with the utility's operations team, Alfa Laval identified that the existing system struggled to handle extreme flow events following heavy rainfall. Australia's climate presents unique challenges for water treatment. Extended droughts and bushfires to sudden heavy rain and flash flooding can significantly affect raw water quality and volume of sediment entering the treatment process.

To ensure the new facility would perform under all conditions, Alfa Laval carried out extensive laboratory testing using water samples collected from the treatment plant in Prospect. Engineers recreated some of the most challenging raw water conditions by adding mud, sand and other materials, evaluating different treatment technologies under controlled conditions.

We spent weeks preparing representative sludge samples and evaluating multiple treatment methods. Because the facility is designed to operate largely unattended, with remote monitoring, reliability and low maintenance were absolutely critical," says the Alfa Laval team.

The results exceeded expectations. The testing consistently demonstrated that the Aldec 50 centrifuge solution produced clear water with minimal residual solids, while generating a dry cake suitable for potential reuse in applications such as road construction composites. Just as importantly, the results remained consistent when the process was scaled up to full operating capacity. The worst water came back clear with little residue, odourless and ready for treatment.

Designed for resilience and flexibility

The new Alfa Laval Aldec 50 decanter centrifuges represent a significant increase in processing capability. Each unit is capable of handling substantially higher flow rates than the previous generation while maintaining a relatively compact footprint and efficient energy consumption.

With our proposal, a single machine can manage the daily workload under normal operating conditions," explains the Alfa Laval team in Australia. "If weather conditions deteriorate, additional units could kick in, and on a really bad day, the four decanter centrifuges would be running simultaneously, providing the flexibility and resilience the system needs."

This scalable approach means the facility can continue operating efficiently during routine conditions while maintaining sufficient capacity to respond to extreme weather events without compromising water quality.

Supporting long-term water security

With construction underway, the new facility will become a critical component of Sydney’s water infrastructure. Beyond increasing treatment capacity, the project will strengthen the resilience of the city's entire water network by providing reliable pre-treatment capability whenever demand peaks or other facilities require maintenance.

Australia's geographic isolation means you can't rely on support from other countries, so this plant needs to perform when the pressure is on," says the Alfa Laval Australia team. "This has been a genuine team effort from all parties, with everyone contributing ideas and working collaboratively to find the best solution. We believe we've developed an innovative approach that will deliver long-term benefits for both Sydney's water supply and the local environment."

The project demonstrates how close collaboration between utilities, infrastructure specialists and technology providers can deliver more than upgraded equipment. Together, we created a smarter, more resilient water system capable of meeting the challenges of a changing climate and a growing city.