POLLUTION CONTROL IN MEAT PROCESSING PLANTS (ABATTOIRS)

PROJECT: Wastewater management system for the Mount Barker Free-range Chicken Processing Plant

Environmental Engineers International Pty Ltd (EEI) was appointed by Mount Barker Chicken (MBC) (http://www.mtbarkerchicken.com.au/), the largest free range chicken processing plant in Western Australia to provide solutions for their air and water pollution problems in 2006.

Background

MBC operated a processing plant with a throughput of 3200 tonnes per year of dressed chicken in 2005. This plant generated 60 to 80 m3/d of wastewater. The existing treatment plant consisted of an anaerobic lagoon, followed by a series of aerobic lagoons and a holding lagoon. The BOD, nitrogen (N), phosphorous (P) values in the treated effluent were very high and apart from the BOD, the N and P remained untreated in the pond system, causing groundwater pollution. The anaerobic lagoon did not have a crust for controlling odour, typically found in anaerobic systems. MBC had tried to provide an artificial crust by adding bird feathers. However, addition of bird feathers did not result in a floating crust, but increased the BOD leaving the anaerobic lagoon instead. The odour emanating from the pond was very strong (odour index of >8) which resulted in neighbours complaining to the regulators to shut down the plant and the issue of an Environmental Protection Notice to address odour issues in 20 days and ongoing air, water soil and pollution problems in 90 days by the regulator. 

Odour Control

EEI provided a quick fix solution to cease odour generation as a temporary step. The recommended solution to raise the pH of the pond system lowered the odour issues immediately, which resulted in support of the local community and the regulators. Within 45 days, EEI designed and installed an artificial floating biofilter system using straw that was placed on the anaerobic lagoon to oxidise the odorous gases.