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Expired beer helps Australian WWTP achieve record bioenergy production

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Millions of litres of beer that expired during Australia’s COVID-19 lockdown has helped to boost renewable energy production at a wastewater treatment plant.

Digesters at SA Water’s Glenelg Wastewater Treatment Plant (WWTP) in South Australia boosted production to 654 megawatt-hours in a single month. The unused beer from local breweries was repurposed on-site and converted into electricity to power the facility’s treatment processes, reducing waste, and benefitting the environment.

Lisa Hannant, SA Water’s senior manager of production and treatment, said the beer was “liquid gold” for the digesters and fuelled record energy generation at the plant. “Our Glenelg WWTP has always been a strong performer in generating its own energy from biogas,” said Lisa, “and the addition of ales and lagers took it to new heights amid the shutdown.

“Glenelg’s co-digestion program adds high strength organic waste from industry to sludge from the sewage treatment process, which is heated in the oxygen-free environment of the large sealed concrete digester tanks, so it breaks down through natural bacterial metabolic processes and releases biogas.

“Harnessing the power of biogas through our on-site gas engines creates renewable energy for the treatment plant and a sustainable alternative for industrial waste that is otherwise difficult to dispose of and treat.”

According to SA Water, beer’s high calorific load and methane potential mean it is perfectly suited to co-digestion, and by adding around 150,000 litres of expired beer per week, the plant generated a record 355,200 cubic metres (m3) of biogas in May and another 320,000 m3 in June – enough to power 1,200 houses.

“Honourably, our thirsty digesters have been doing their bit for the environment by drinking themselves silly and with such a horrific diet, it’s no wonder they produce so much gas!” said Hannant.