Water recycling from palm oil mill effluent (POME) using membrane technology

Abstract

Malaysia is the largest producer and exporter of palm oil. Palm oil processing is carried out in palm oil mills where oil is extracted from a palm oil fruit bunch. Large quantities of water are used during the extraction of crude palm oil from the fresh fruit bunch, and about 50% of the water results in palm oil mill effluent (POME). POME is a thick brownish liquid that contains high amounts of total solids (40,500 mg/L), oil and grease (4000 mg/L), COD (50,000 mg/L) and BOD (25,000 mg/L). The disposal of this highly polluting effluent is becoming a major problem if it is not being treated properly besides a stringent standard limit imposed by The Malaysian Department of Environment for effluent discharged. A POME treatment system based on membrane technology shows high potential for eliminating the environmental problem, and in addition, this alternative treatment system offers water recycling. The treated effluent has a high quality and crystal clear water that can be used as the boiler feed water or as the source of drinking water production. In our current research, a pilot plant was designed and constructed for POME treatment; two stages of treatment have been conducted whereby coagulation, sedimentation and adsorption play their roles at the first stage as a membrane pretreatment process, and ultrafiltration and reverse osmosis membranes are combined for the membrane separation treatment. Results from the total treatment system show a reduction in turbidity, COD and BOD up to 100%, 98.8% and 99.4%, respectively, with a final pH of 7. Thus, the results show that this treatment system has a high potential for producing boiler feed water that can be recycled back to the plant.