Kinetics study of bioremediation of industrial effluents by Pseudomonas spp and Bacillus spp using chemical oxygen demand (COD)

Abstract

The kinetics study of effluents from food and detergent industries were carried out. Two different bacteria Pseudomonas spp and Bacillus spp were isolated from food effluent (FE) and detergent effluents (DE) and were used for their bioremediation respectively. Reductions in the chemical oxygen demand (COD) of the effluents were studied as indication of bioremediation of the effluents. The overall result showed that the reduction in the chemical oxygen demand (COD) for the food effluent and detergent effluent at 5g of micro-organism (OW5g) was 78.70% and 84.47% respectively while those of 10g of micro-organism (OW10g) were 91.11% and 87.76% respectively. At 50% dilution of the effluents and 5g of the micro-organism (DW5g) the reduction in COD was 96.83% and 88.73% for food effluent and for detergent effluent respectively. The reductions in COD were subjected to zero and first order kinetics. The rate constant for COD reduction at 5g of micro-organism for zero order and first order kinetics were (COD-F 33.8mg/l/d and 0.061d-1) and (COD-D 31.7 mg/l/d and 0.067d-1) respectively. The rate constants for COD reduction at 10g of micro-organism for zero order and first order kinetics were (COD-F 31.09mg/l/d and 0.123d-1) and (COD-D 32.4mg/l/d and 0.085d-1), while those at 50% dilution with 5g of micro-organism was (COD-F 30.8mg/l/d and 0.786d-1) and (COD-D 28.45mg/l/d and 0.14d-1). The kinetic models results showed that both the COD reduction for pseudomonas spp. and bacillus spp. used in this research followed both the zero order and first order kinetics. However, while zero order kinetics was best fitted for the original sample with 5g of immobilized microorganisms, first order kinetics was well fitted when the concentration of both effluents was reduced by 50% with 5g immobilized microorganisms and original sample with 10g of the immobilized microorganisms.