Integrated of Membrane Separation withPretreatment Process for Palm Oil Mill Effluent(POME) Disposal

摘要

Malaysian is one of the largest producers of palm oil. Most of the palm oil processing is carried out in palmrnoil mills where oil is extracted from palm oil fruit bunch. Every tonne of fruit bunch processed produces 1.5rntonne of palm oil mill effluent (POME) contains high amount of total solids (40, 500 mg/L), oil (4, 000rnmg/L) and BOD (25, 000 mg/L). Current biological treatment technologies such as aerobic and anaerobicrndigestion systems have inherent problems of operation and maintenance. Palm oil mill uses substantialrnquantities of water. Therefore, palm oil industry has a vested interest in all feasible water recovery andrnpollution abatement technologies. Membrane technology (reverse osmosis/ultrafiltration systems) has beenrnused in industry for economical recovery and purification of large volume of water. An integrated treatmentrnsystem comprised of membrane separation with pre-treatment unit operations has been designed for therntreatment of POME.rnThe pre-treatment process has two stages of separation, first stage is the removal of suspended solidsrnusing coagulation and settling and the second stage is removal of oil and grease using solvent extraction.rnBoth treatments are important to reduce membrane fouling at the later stage. Effect of pH, coagulantrnconcentration, mixing time and solvent to oil ratio were studied to find the optimum condition for the pretreatmentrnprocess. Preliminary studies show that 65 % oil and grease in POME can be removed usingrnsolvent extraction. Data also shows that alum as a coagulant at 4, 000 ppm and pH 4.41 can remove up torn80% of suspended solids in POME with flocculation process.rnThe pre-treated effluent is passed to the membrane separation unit containing a cross flow ultrafiltrationrnmembrane module. The flux data were obtained under different operating conditions. The residual oilrnpresent in pre-treated effluent was also removed by membrane, however the flux values dropped due to oilrnfouling. Experiments are in progress to study the effect of fouling over the membrane performance.