Fuzzy optimisation approach on the treatment of palm oil mill effluent (POME) via up-flow anaerobic sludge blanket–hollow centered packed bed (UASB–HCPB) reactor

An optimization study on the mesophilic anaerobic treatment of palm oil mill effluent (POME) in an up-flow anaerobic sludge blanket–hollow centered packed bed (UASB–HCPB) reactor was conducted for the first time by using kinetics modeling. Monod model was opted for the optimization due to its capability of describing the anaerobic digestion and the involvement of adequate amount of parameters in the kinetics model. The best-fit kinetic constants obtained from previous work were incorporated in the optimization model. Fuzzy optimization was adopted and it yielded the optimized chemical oxygen demand (COD) removal of 86.7% and volumetric methane production rate of 0.448 LCH4/L.day at hydraulic retention time (HRT) of 4.33 days, organic loading rate (OLR) of 14.75 gCOD/L.day and mixed liquor volatile suspended solid (MLVSS) concentration of 19,130 mg/L. A confirmative experiment was conducted and the results validate the legitimacy of the fuzzy optimization model. Further studies are required to improve the reliability of this newly introduced optimization technique in the wastewater treatment industry.