Biodeodorization of Barrels Containing Natural Gas Odorants by Bacillus cereus

All sulfur organic odorants used in the Iranian gas industry enter the country in 200-liter barrels. There are ways to clean up the empty barrels contaminated with these materials. In the Gas Company, the currently used method is chemical oxidation (using sodium hypochlorite and caustic). In this study, the biological desulfurization and degradation method of mercaptan was studied. Desulfurizing bacteria in the university microbial collection, together with bacteria isolated from gas odorant barrels, were examined, among which one of the species had the highest and fastest decomposition rate. This bacterium belongs to the Bacillus cereus family. The most important factors affecting biological desulfurization including initial bacterial concentration, the concentration of odorant, and the Oil Fraction Phase (OFP) were optimized. These three factors were studied using an experimental design. Initial bacterial concentrations were evaluated at five levels from 10 to 50 ml with an optimum concentration of 30 ml. The OFP was also evaluated at five levels from 10 to 90%, with 50% being optimized. Concentrations of odorant were also evaluated from 2500 to12500 ppm, with an optimum concentration of 7500 ppm. Operational testing was carried out in one of the barrels in the optimized conditions for 48 h. The results showed 79.8% efficiency in removing odorant.