AUSTRALIA, North Sydney. A green energy initiative by the Japanese meat processor NH Foods at its Oakey Beef Exports plant in Australia has been hailed as a “poster child” for food producers worldwide.
The Global Water Engineering (GWE) Cohral plant opened this month to extract green energy biogas from its waste water streams. This will in turn replace millions of dollars’ worth of natural gas currently consumed at the abattoir on Queensland’s Darling Downs. The plant, the first GWE covered high-rate anaerobic lagoon in the world, will produce 183.3 gigajoules of energy a day when it reaches design capacity through the combustion of methane produced.
It also delivers high-quality waste water by extracting organic content, which it converts into methane to replace fossil fuels. The anaerobic digestion technology involved can remove over 90% of organic waste content. The green energy produced represents 40% of the plant’s current usage of natural gas and will produce direct ongoing savings year after year. The cost of construction is expected to be repaid inside five years.
Additional benefits include reduced greenhouse gas emissions, improved quality of wastewater and greatly reduced odour emissions from the plant.
Ian Macfarlane, the federal industry minister, said other countries would take note of the project.
The Oakey plant is already one of Australia’s largest beef export plants. It is currently undergoing an expansion to increase production from 298,000 head a year to 560,000, with employment rising from 750 to as many as 1,400.
In addition to lowering the plant’s dependence on increasingly expensive supplies of natural gas, the GWE anaerobic digestion plant will simultaneously produce waste water far cleaner than typical waste lagoons. Cohral technology uses concentrated anaerobic bacteria to digest 70 to 85% of the organic matter in Oakey’s waste water to produce effluent of higher quality than typical open lagoons.
Closed tank designs can achieve even higher digestion levels, with more than 90% efficiency achieved in service by GWE plants. The biogas storage design selected for Oakey Beef – a 6,000 m3 capacity flexible PVC-coated polyester fibre flexible storage balloon – is engineered to be permanently gas-tight.