Isolation and Characterization of a Bacillus Strain for Alkaline Wastewater Treatment

Biological treatment is one of the considerable choices for removing of organic pollutants present in petrochemical wastewaters. In this study, five strains, named as BS1, BS2, BS3, BS4 and BS5, were isolated from sludge nearby a petroleum smelter. BS5, the isolate with the highest COD removal rate, was identified as Bacillus flexus, based on 16S rDNA sequences. Subsequently, the optimized COD removal conditions of BS5 were investigated. It was indicated that the optimal conditions were 0.5 % corn starch, 1 % corn steep liquor, 35 C, pH 7.5, and 10 % (v:v) inoculation size. Under such circumstance, the removal rate of COD can reach 81.04 %. The isolation of Bacillus flexus strain BS5 provided an alternative for the bioremediation of alkaline wastewater. Lastly, the study showed that consecutive disposal process may help to reducing COD of wastewater effectively.