ABSTRACT

The biodegradation of effluent generated from palm oil mills were evaluated. The optimization of cultural conditions for degradation by the isolated organisms and assessment of the effluents as a fermentative media for protease and lipase production were also determined. High association of Chemical Oxygen Demand (COD) (69000- 130000mg/i), ammonia-nitrogen (127 — 298mg/i), Total Kjedahl nitrogen (TKN) (780- 1400mg11), phosphate (P043) (80-86mg/I), and Sodium (Na+) (69 -75mg/i) contents of the effluent samples were connected with palm fruits processing. 1-ugh level of oil and grease ( 6700-9000mgI), free fatty acid (147.6-277.2mg/i), Total solid (TS) (3800 — 4500 mg/l), Total dissolved (TDS) (1614 - 2175mg/i) , Total suspended solid (TSS) (1500 - 2350 mg/I ), temperature ( 32-38°C), coupled with low p1-I range (3.74 to 4.57), alkalinity (42 and 58mg/i) and high Biochemical Oxygen Demand (BOD) (12000 - 18000mg/i.) were characteristic of the wastewater effluents. Microbial isolation, Q characterization and screening for degradation and metabolic activities in palm oil mill effluent showed that Pseudonionas acruginosa, Bacillus cere us, Candida rugosa and Geotrichum candidium had the great potentials in the degradation of palm oil mu effluent. All the isolates can remove fat and oil by 64.3% - 77.5% in palm oil wastewater after 7days of incubation. The decrease in COD was found to be 17.2%- 29.2%. Comparative degradation ability of the selected isolates revealed that Pseudomonas aeruginosa had, the best degradation ability with oil and greae reduction (1717mg/I) representing 77.5%, BOD (9990mg/I) 33.6%, COD (55775mg/i) 29.2% and TSS (591mg/i) 64.2% reduction. Nutrient balance with respect to carbon, nitrogen and metal ions not only supported growth but enhanced degradation of organic compounds in palm oil wastewater. Under optimal conditions, the rate of COD reduction was maximal. The microbial cultures were successfully used to treat palm oil wastewater effluent with improves pH and decreases in parameters with respect to COD, BOD, and TDS. All four strains also produced lipase and protease which stimulated better waste treatments.