REMOVALS OF ORGANIC AND NITROGEN IN BIOGAS EFFLUENT BY AAO SYSTEM

Abstract

Livestock wastewater effluents containing high content of organic and nutrients are discharged to the receiving water environment. Although wastewater is treated by biogas digester, the effluent concentrations still remain high in COD, ammonium (NH₄⁺) and phosphate (PO₄^3-). This research used a three-chambers system anaerobic-anoxic-aerobic (AAO) for simultaneous removal of organic, nitrogen pollutants via continuous experiments. The biogas effluents with COD (2000-5000 mg/L), NH₄⁺ (155-188 mg/L), PO₄^3- (13.00-21.95 mg/L) were used as influences for the continuous experiments. The results show that removal efficiency of COD and NH₄⁺ were achieved at 82% and 70%, respectively. The concentration of COD was obtained at the safe level regulated by the QCVN 62-MT:2016/BTNMT. To optimize the AAO system for higher input concentrations of pollutants, a further study on operation conditions such as hydraulic retention time and oxygen supply should be conducted.