Performance and kinetic evaluation of an integrated anaerobic–aerobic bioreactor in the treatment of palm oil mill effluent

Abstract

ABSTRACTThis work presents the evaluation of biokinetic coefficients for a novel integrated anaerobic–aerobic bioreactor (IAAB) at different organic loading rates (OLRs) (10.5–22.5 g COD/L per day) treating palm oil mill effluent. The overall efficiencies of the chemical oxygen demand (COD) and biochemical oxygen demand (BOD) were more than 99% for OLR up to 19.5 g COD/L day with biogas production containing 48–64% of methane. The effluent quality remained stable (BOD < 80 mg/L) and satisfied with the discharge limit. Stover–Kincannon model was the most appropriate model to estimate the performance of anaerobic compartment of IAAB, while Monod model was best suited for describing the aerobic compartment.Abbreviations: BOD: biochemical oxygen demand; COD: chemical oxygen demand; DO: dissolved oxygen; GLSS: gas–liquid–solid separator; MLSS: mixed liquor suspended solid; MLVSS: mixed liquor volatile suspended solid; POME: palm oil mill effluent; RAS: returned activated sludge; SBR: sequencing batch reactor; SVI: sludge volume index; TA: total alkalinity; TN: total nitrogen; TS: total solids; TSS: total suspended solids; UASB: upflow anaerobic sludge blanket; UASFF: upflow anaerobic sludge blanket fixed film; VFA: volatile fatty acid; VSS: volatile suspended solids