Production of methane as bio-fuel from palm oil mill effluent using anaerobic consortium bacteria

Abstract

Consortium of bacteria (Bacillus toyonensis strain BCT-71120 and Stenotrophomonas rhizophila strain e-p10) can reduce biological oxygen demand (BOD) and chemical oxygen demand (COD) values in aerobic fermentation process of POME. This study aims to degrade the organic and inorganic compounds in POME by using anaerobic bacterial consortium of Bacillus toyonensis strain BCT-71120 and Stenotrophomonas rhizophila strain e-p10 to produce biogas and reduce the values of COD, BOD and total suspended solid (TSS). Effect of fermentation time on TSS, COD, BOD and pH are investigated. Specific growth rate and generation time are determined to obtain optimal fermentation time. The results shows that the bacterial consortium of Bacillus toyonensis strain BCT-7112 and Stenotrophomonas rhizophila strain e-p10 reduced COD, BOD and TSS values of POME and produce methane in biogas for 18 d of anaerobic fermentation process. The highest reduction of COD, BOD and TSS were 86, 94 and 80%, respectively, while the highest methane content was 41.05%. The pH values ranged from 7.8 to 8.3 as sufficient condition for the bacterial growth. The highest specific growth rate of the bacteria achieved at 0.268 1/d and the lowest generation time was 3.74 d. Values of μmax and Ks were achieved 0.174 1/d and 63.011 mg/L, respectively. Value of Y = 1.4 × 109 CFU/mg, Kd = 0.42 1/d and qmax = 1.24 × 10−10 mg/CFU.d based on BOD values. Values of μmax and Ks were achieved 0.122 1/d and 5.945 mg/L, respectively. Y = 2.41 × 109 CFU/mg, Kd = 6.60 1/d and qmax = 5.062 × 10−10 mg/CFU.d. based on COD values.