Waste & Resource Recovery

Generated biogas creates cleaner wastewater effluent in plant

A generated biogas, used directly in a food plant’s existing boiler, is helping to reduce carbon footprint, lower energy costs and provide cleaner wastewater effluent.

By replacing natural gas with biogas a plant in southern Queensland is reducing fossil fuel use and sharpening cost-efficiencies at a time they are most needed, due to the current Australia-wide drought.

The green energy initiative is part of meat processor NH Foods Australia’s process at its Oakey Beef Exports facility.

As part of the initiative, the Global Water and Energy (GWE) COHRAL (covered high-rate anaerobic lagoon) system was installed at Oakey by Australian environmental engineering and green energy authority CST Wastewater Solutions.

CST found that the clean, compact and robust plant is in better condition, having required only routine maintenance over that time, as it continuously produces 3,000-4,000 cubic metres of biogas a day, depending on plant throughput.

Waste at Oakey is converted to biogas by an anaerobic digestion process applicable to many foods, beverage or primary processing plants with similar waste streams high in organic content.

The GWE anaerobic digestion plant in Queensland’s Darling Downs region produces green energy in the form of biogas from Oakey Beef Export’s wastewater streams, replacing millions-of-dollars’ worth of natural gas over its operating life.

The necessary pre-treatment before the GWE COHRAL system leads to recoveries of valuable protein and fats, which would normally end up in the wastewater.

This can be classified as an indirect benefit to the bottom line, as well as increasing treatment system reliability by isolating such problematic waste from the high-performance WWTP (Waste Water Treatment Plant).

CST managing director Michael Bambridge said the wind doesn’t need to blow, and the sun doesn’t need to shine, to produce this green energy, which gives it both advantages over, as well as complementing the many excellent solar and wind energy systems suited to other projects.

“Right now, the Oakey plant is delivering cost-efficiency benefits at a time when they are most needed, when the plant has to operate efficiently, while coping with herd reductions resulting from the drought,” said Brambridge.