Physico-chemical and enzymatic pre-treatment for wastewater from slaughterhouse

ABSTRACT

The effluent generated in a poultry slaughterhouse, containing fat (quantified by oil and grease - O&G analysis) at a concentration of 1,100 mg.L^-1, was subjected to two pre-treatments to reduce the particulate organic matter concentration: a conventional physicochemical treatment (coagulation/flocculation with ferric chloride) or an alternative enzymatic treatment (enzymatic hydrolysis), applied alone prior to the biological process for removing dissolved organic material. Hydrolysis was performed with 0.5% (m/v) of a solid enzymatic preparation (SEP - containing 8 lipase activity units per gram) produced by the fungus Penicillium sp. for 8 h at 30ºC. Different conditions were evaluated in the coagulation/flocculation, and the one with the best total COD removal for feeding bench top aerobic and anaerobic bioreactors was selected: pH = 5.0 and 400 mg FeCl₃.6H₂O.L^-1. Better results were achieved when using the physicochemical pre-treatment with average COD removals of 91% in aerobic and anaerobic treatments.

Keywords:
slaughterhouse; coagulation/flocculation; enzymatic hydrolysis; wastewater; biological treatment