Strategies for dealing with piggery effluent in Australia: the sequencing batch reactor as a solution

Abstract

Currently the accepted practice for swine wastewater disposal is lagoon stabilisation followed by land application. This disposal method can exacerbate odour emissions and contribute to soil contamination and eutrophication of waterways. Intensification of the pig industry has increased the impact of individual piggeries; this combined with tightening legislation is causing the pig industry in Australia to look at alternative treatment methods. A pilot scale sequencing batch reactor (SBR) was built to treat piggery wastewater. It achieved NH4+ and odour reductions of greater than 99% as well as 79% removal of COD and a 49% reduction of PO43−on a mass balance basis. The reactor experienced problems with foaming for the first 2 months of operation, which was controlled with vegetable oil until the foaming stopped. Struvite formation also occurred within the reactor and influent pipes but it was calculated that sufficient nutrients were removed to prevent precipitation down stream of the SBR.