TOU designed and managed the construction and commissioning of a large open-bed biofilter for a rendering plant at a new abattoir in Singleton NSW. The project also involved the design of the foul air collection system within the rendering building.

The system design was the first approved by the EPA for rendering plants where only highly odorous process air was collected and treated, with the remaining fugitive emissions of odour being allowed to vent to atmosphere through axial flow roof fans. The system performance is dependent upon the efficient capture of the process emissions, leaving minimal odour in the fugitive emissions.

The total process foul air flow rate is 40,000 m3/hr. The biofilter has a bed area of 360 m2, arranged in 3 pairs of cells. A spray-column humidifier saturates the foul air stream prior to biofiltration. Six months after commissioning the biofilter was found to be reducing the odour concentration from 11,500 OU/m3 to 90 OU/m3. The fugitive emission through the roof vents was measured at 180 OU/m3.

The system represents current best practice for odour control in the meat processing industry in Australia.