Bioremoval of trichloroethylene/toluene mixture by Burkholderia vietnamiensis G4 from water

Environmental contamination by mixed organics has become the most important environmental issues. As mixed wastes, petroleum/gasoline compounds and such chlorinated compounds as trichloroethylene (TCE) are among the most frequently found subsurface contaminants. Especially, TCE is considered among the most frequently found groundwater contaminant around the world. This study is investigating the bioremoval of these compounds when present in mixture and better removing these mixtures from the contaminated water, using combined physical and biological methods. The effects of different concentrations of TCE (0.5, 1 and 1.5 mg/L), toluene (50, 100 and 150 mg/L) as growth substrate, inoculum (Burkholderia vietnamiensis G4; optical density, 1 and 3), activated carbon (1 and 3%, w/v) and dissolved oxygen (with or without additional oxygen source, hydrogen peroxide) on the aerobic removal of TCE/toluene mixture were investigated and the conditions were further optimized. The overall optimal condition for the bioremoval of TCE/toluene mixture was found at toluene 150 mg/L, TCE 1.5 mg/L with 3% powdered activated carbon, without hydrogen peroxide with initial optical density 1 in mineral medium. Results obtained would provide a better understanding of interactions among contaminants even before the application of any remediation technology and would enhance the applicability of the combined remediation technology to the mixed waste contaminated environmental sites.