Assessing a New Approach to Covered Anaerobic Pond Design in the Treatment of Abattoir Wastewater

Abstract

Churchill Abattoir Pty Ltd (CA) is a beef abattoir and rendering facility that has operated for 43 years as a government entity, and for the past 11 years as a private enterprise. Since the changeover, there have been significant improvements in CA’s environmental performance. In response to improving waste treatment and minimisation, CA has developed a novel covered anaerobic pond design for the treatment of abattoir wastewater. This design consists of five smaller ponds arranged in a cell configuration which has been driven by a number of factors including, manageability (for desludging ponds) and ease of removing and applying covers. Industry design and management standards are based on generalised metrics for anaerobic ponds rather than industry specific data. To inform pond design, an intensive study of pond behaviour was performed on the covered anaerobic ponds. This paper gives an overview of the literature reported on the use of anaerobic ponds in the treatment of high-strength wastewater and outlines the key findings in the preliminary assessment of the behaviour and performance of these novel anaerobic ponds. The use of five smaller ponds instead of one larger pond has proven successful in terms of crust and sludge removal. The primary issue with the covered ponds at Churchill, however, was the build-up of fat/crust that prevented the capture of biogas and effective use of the cover. Despite the operational difficulties in relation to fat/crust accumulation, results indicate that satisfactory, stable operation has been achieved for the smaller five-pond system, notwithstanding the higher than desired organic loading rate of the two primary ponds.