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

Currently the accepted practice for swine wastewater disposal is lagoon sta bilisation followed by land application. This disposal method can exacerbat e odour emissions and contribute to soil contamination and eutrophication o f waterways. intensification of the pig industry has increased the impact o f individual piggeries; this combined with tightening legislation is causin g the pig industry in Australia to look at alternative treatment methods. A pilot scale sequencing batch reactor (SBR) was built to treat piggery wast ewater. It achieved NH4+ and odour reductions of greater than 99% as well a s 79% removal of COD and a 49% reduction of PO(4)(3-)on a mass balance basi s. The reactor experienced problems with foaming for the first 2 months of operation, which was controlled with vegetable oil until the foaming stoppe d. Struvite formation also occurred within the reactor and influent pipes b ut it was calculated that sufficient nutrients were removed to prevent prec ipitation down stream of the SBR.