NH Foods sees gains with GWE biogas system

A green energy initiative made by the meat processor NH Foods Australia at their Oakey Beef Exports facility, is paying handsome dividends in terms of cleaner wastewater effluent, as well as a reduced carbon footprint and lower energy costs.

The Global Water & Energy (GWE) COHRAL™ (Covered High-Rate Anaerobic Lagoon) system was installed at Oakey by Australian environmental engineering and green energy authority CST Wastewater Solutions, which recently inspected the plant, as it approaches its landmark fifth year of service in southern Queensland.

CST found that the clean, compact, and robust plant is in outstanding condition, having required only routine maintenance over that time, as it continuously produces 3000-4000 m³ of biogas a day, depending on plant throughput.

The generated biogas is directly used in the plant’s existing boiler, replacing natural gas. This leads to a reduction in fossil fuel use and sharpened cost-efficiencies at a time they are most needed, due to the current Australia-wide drought.

The GWE anaerobic digestion plant 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, in Queensland’s Darling Downs region.

Instead of effluent being managed in the energy-intensive and space-consuming aerated lagoons used by many food and beverage businesses – with all of their associated environmental, OH&S hazard, water and odor issues – waste at Oakey is converted to biogas by a clean, green and reliable anaerobic digestion process applicable to many food, beverage or primary processing plants with similar waste streams high in organic content.

The gas balloon

The robust lagoon cover under which anaerobic bacteria convert waste to biogas, which is then stored in the balloon.

The compact GWE COHRAL™ plant involved occupies just half the footprint of comparable covered anaerobic lagoons and much smaller space than that required by typical energy-hungry and often-odorous, open aerated lagoons that are in service in similar applications globally.

The necessary pretreatment before the GWE COHRAL™ system also leads to superior recoveries of valuable protein and fats which would normally end up in the wastewater.

This could 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).

By transforming a wastewater treatment and disposal problem into an ongoing productive asset, the plant has achieved a rare business and environmental ideal of overall cleaner, greener factory performance, via stable, predictable waste treatment and profitable supplies of biogas.

“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. Ultimately, the plant will pay for itself with biogas then go on to produce virtually free energy for many years after that,” said Mr. Bambridge.

“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. Its success is clearly demonstrating the value in service of a technology that is widely applicable to the food, beverage and primary processing industry.”

The Oakey plant is designed to produce biogas (primarily methane) which is stored for use in a 6000m³ capacity, flexible, PVC-coated polyester storage balloon from which it is drawn to fuel the boiler, as needed. 

The new plant simultaneously delivers high quality treated wastewater by biologically removing organic content, which it converts into methane to replace fossil fuels, as a secondary benefit. The GWE technology involved removes 80-90 percent of the organic content, minimizing the need for final polishing, while also reducing odors from the overall WWTP.

“Oakey Beef Exports is one of the most modern meat works in Australia and one of the country’s largest beef export plants.  Operating in a global market, as a premium exporter to 34 countries, means its manufacturing processes need to be respectful, sustainable and efficient,” says Mr. Bambridge.

The installation of GWE COHRAL™ technology at Oakey is another excellent example of the widely-proven GWE anaerobic technologies used in more than 400 plants worldwide in a wide variety of industries.