Maximising anaerobic digestion via recuperative thickening

The Eastern Treatment Plant (ETP) uses an anaerobic digestion process to break down and stabilise the solids produced by the treatment process, and to generate biogas which powers renewable energy generation. Due to Melbourne’s rapidly growing population, the existing digesters are approaching capacity.

Anaerobic digestion process at Eastern Treatment Plant

To increase the plant’s digestion capacity without the cost of building more digesters, Melbourne Water is implementing a recuperative thickening upgrade. This involves taking sludge exiting the digesters and thickening it, before returning it to the digesters for further treatment.

The decision to implement such a process followed a broad-ranging survey of available technologies, and was backed by an innovative, laboratory-scale study of three short-listed options. This testing took into account properties unique to the ETP, such as sludge digestion and flow characteristics, ensuring the most appropriate process was selected.

Melbourne Water has developed a staged implementation plan for the recuperative thickening upgrade. This will provide additional short-term capacity while retaining flexibility to account for any growth in population and technological developments. It will also drive the maximum value from our existing assets, contributing to more affordable services for our customers.

Stage 1 of recuperative thickening is currently out to tender, with completion expected in early 2021.

Last updated:
19 April 2021