Recent advancements in the treatment of palm oil mill effluent (POME) using anaerobic biofilm reactors: Challenges and future perspectives.

Palm oil is the most utilized vegetable globally which is mostly produced in countries such as Malaysia, Indonesia and Thailand. The great amount of POME generation from palm oil mills is now a threat to the environment and require a suitable treatment of POME to reduce the organic strength in accordance with the standard discharge limit before releasing to the environment. Currently, the technology to combine the anaerobic process and biofilm system in bioreactors have produced a fresh idea in treatments of high strength wastewater like POME. Anaerobic biofilm reactor is a convincing method for POME treatment due to its significant advantages over the conventional biological treatments consisting of anaerobic, aerobic and facultative pond systems. Overall, integrated anaerobic-aerobic bioreactor (IAAB) can remove more than 99% of chemical oxygen demand (COD), biochemical oxygen demand (BOD) and total suspended solids (TSS) with the combination of anaerobic and aerobic digestion for POME treatment. It has better performance as compared to up-flow anaerobic sludge blanket (UASB) and up-flow anaerobic filter (UAF) with 80% and 88-94% COD removal efficiency respectively. Anaerobic pond was found to perform well also by removing 97.8% of COD in POME but require long retention time and larger land. Hence, this study aims to provide intensive review of the performance of the anaerobic biofilm reactor in treating POME and the recent advancements in this technology. The limitations and future perspectives in utilization of anaerobic biofilm reactor during its operation in treating POME are discussed.