Treatment of Palm Oil Mill Effluent by a Microbial Consortium Developed from Compost Soils

A method for the aerobic treatment of palm oil mill effluent (POME) was investigated in shake-flask experiments using a consortium developed from POME compost. POME was initially centrifuged at 4,000 g for 15 min and the supernatant was enriched with (NH 4 ) 2 SO 4 (0.5%) and yeast extract (0.25%) to boost its nitrogen content. At optimum pH (pH 4) and temperature (40°C) conditions, the chemical oxygen demand (COD) of the effluent decreased from 10,350 to 1,000 mg/L (90.3%) after 7 days. The total bacterial population determined by plate count enumeration was 2.4 × 10 6  CFU/mL, while the fungal count was 1.8 × 10 3 colonies/mL. Bacteria of the genera Pseudomonas, Flavobacterium, Micrococcus , and Bacillus were isolated, while the fungal genera included Aspergillus, Penicillium, Trichoderma , and Mucor . When the isolated species were each inoculated into separate batches of the raw effluent, both pH and COD were unchanged. However, at 75 and 50% POME dilutions, the COD dropped by 52 and 44%, respectively, while the pH increased from 4 to 7.53. POME treatment by aerobic method is sustainable and holds promising prospects for cushioning the environment from the problems associated with the use of anaerobic systems.