Australian first biogas project for water recycling plant
Posted 20 October 2016
A Victorian water recycling plant has debuted Australia’s first thermophilic anaerobic digestion process (TPAD), touted to break down organic matter faster than alternative processes.
The $60 million upgrade of South East Water’s Mt Martha Water Recycling Plant includes a tertiary treatment plant which, at its peak, will produce 26ML of Class A recycled water per day.
TPAD uses the biogas from the digestion process to heat the material to 55 degrees, growing bacteria that deactivates pathogens and removes volatile organic content more quickly.
This varies from traditional anaerobic digestion processes that only maintain organic matter at body temperature during treatment.
This method is not only more efficient, but also reduces the plant’s environmental impact by utilising more of the methane generated and produces less odour.
A by-product of the treatment process is the creation of biosolids, which the plant aims to reuse in the form of fertiliser.
As part of the upgrade the plant also added two solar dryers for drying the biosolids. The dryers provide an alternative to open-air drying pans, which are less efficient and produce more odour.
The dryers are able to cut the drying time of biosolids from one year to as little as two months, generating more fertiliser in less time, and using less energy than other technologies.
In addition to their increased output speed, the dryers also use a fraction of the energy required by gas-powered dryers.
South East Water now has five solar dryers and produces more than 3000 dry tonnes of biosolids each year.