Decolorization of palm oil mill effluent using selected indigenous bacteria

Abstract

In this study, the selection of suitable bacteria that is best to treat POME from final pond is the main objective. There are 20 bacteria that had been isolated from final pond of POME but only 11 species has the ability to reduce color of POME. However, only five strains out of 11 species were capable to reduce the color after 6 days of incubation compared to others which took longer time. Bacteria D showed the best results in reducing the color of POME which was 45% (from 4437 to 2448 ADMI) after 6 days of treatment. Partial identification of bacteria D using biochemical test showed that it belonged to Proteus inconstans. Results showed that POME wastewater treated with indigenous bacteria D successfully reduced the COD level up to 61 % (from 34170 to 13464 mg/L), pH value from 9.25 to 9.11 at day 2, 19% of lignin contents (from 310 to 250 mg/L), 17% of phenolics compound (from 271 to 225 mg/L), 47% (from 5202 to 2754 ADMI) of color intensity (ADMI) respectively. The highest lignin peroxidase activity was 1.94 U/mL implying the optimum bacterial activity occurred during the exponential growth phase. The study suggested that isolated indigenous bacteria could decolorize POME wastewater.