Water treatment at the source

Western Water’s Rosslynne Water Filtration Plant (WFP), located in Gisborne, Victoria, has had an innovative water treatment process implemented that will help to provide high-quality water to local properties.

The plant was shut down during the Millennium Drought after the Rosslynne Reservoir dropped to below 4% of its 25,400 ML capacity, at which point customers in the Macedon Ranges were switched to the Melbourne drinking water system. When the plant was reopened, its water quality was found to be not up to standard.

The reservoir refilled in 2011 and 2012, swamping vegetation that had grown on the edges and leading to high levels of organics in the water. The existing plant was unable to treat these levels.

Western Water worked with consulting company GHD to tailor a solution. The innovation was to dose powdered activated carbon (PAC) at concentrations tailored to achieve the required removal of variable dissolved organic carbon (DOC) levels in Rosslynne source water. The PAC particles loaded with DOC are removed by the existing dissolved air flotation process at the plant.

Running from May 2012 to January 2014, the project involved bench- and full-scale pilot testing, followed by full-scale construction at the existing Rosslynne WFP. In addition, works to optimise the removal of manganese and to fluoridate the treated water were implemented.

“This is an excellent example of how innovative thinking can help water utilities reduce costs and create additional value from their existing assets,” said GHD Project Director Michael Chapman. “This solution builds on GHD’s work with Western Water towards an integrated sustainable water supply strategy.”

With greater utilisation of the local water supply, there will be less need to buy and pump water from Melbourne. As noted by Western Water Managing Director Neil Brennan, this will save on costs and emissions.

Brennan further stated, “With work on a pipeline to the town of Lancefield now underway, all our Macedon Ranges towns will have access to high-quality local water.”