Hundreds of thousands of litres of beer which brewers couldn’t sell in venues during the COVID-19 lockdowns has been used to create green energy in South Australia.

Breweries including Pirate Life and Big Shed Brewing Concern had beer in kegs passing its ideal freshness was taken on by SA Water.

The utilities organisation added 150,000 litres of expired beer to its anaerobic digestors within its wastewater treatment plant at Glenelg every week, and generated 355,200 cubic metres of biogas in May and another 320,000 in June.

Joshua Zugajev of SA Water said that the innovative solution came in response to the excess of beer.

“Brewers had an abundance of product to dispose of and beer is not something you can easily get rid of – normally they wouldn’t have to get rid of this much, and you can’t just tip it down the drain because of the volume and nature of the material.”

Wastewater that travels from homes and businesses makes its way to treatment plants, where it is filtered into water and sludge to go through Glenelg’s anaerobic digesters.

“They’re completely sealed and have floating roofs on them which move up and down as the sludge produces biogas, through that anaerobic process where the bacteria starts eating away and the biogas is a product of that process.

“The beer is added at this stage and provides additional food and energy for the bacteria to be used in that process.”

While the bacteria are often fed other organic materials, normally liquid waste from industries such as dairy, beer was a treat for the micro-organisms.

“In this case we provided the beer, it’s got a big calorie load so it’s perfect for this application, and great food for the bacteria.”

The increased activity of the bacteria produced a record amount of biogas, Zugajev explained.

“The end result is that it boosted biogas production and set a new record for energy generation at that site.

“Normally we’re about 80 per cent energy self sufficient. Once the biogas is produced we pipe it through to three electricity turbines and they then burn the gas, turn and produce electricity, and run the operations at the plant.

“We’d normally produce about 290-300,000 cubic metres in a month, and in July we produced 371,000 cubic metres – the highest we’ve ever produced at that plant as a result of some of that additional waste.”

Zugajev said that its trade waste team connected with the brewers to see if they were interested in disposal, but doesn’t expect it to be an ongoing project.

“It would be unusual for it to happen again, it was just the nature of the COVID crisis, that it took most of us by surprise, and the brewers were not able to plan and foresee this event so they were left with expired product.

“I would hope that through people having more visibility and probably wouldn’t have the same situation again, but we have an ongoing programme where we accept waste, dairy products, some of the wine industry byproducts.

“We’ll continue to do that with other industries, but hopefully the beer will end up where it’s intended!”