Bioremediation of Mixed Wastes (BTEX, TPH, TCE, and cis-DCE) Contaminated Water

Together with industrialization, more sites have become contaminated with mixed wastes of organics. Contamination of groundwater with benzene, toluene, ethylbenzene, and three isomers of xylene (BTEX) and chlorinated aliphatic hydrocarbons (CAHs) allows for the application of aerobic bioremediation to achieve mineralization of both types of compounds. In this study, the aerobic bioremoval of mixtures of these compounds [BTEX, BTEX/trichloroethylene (TCE), BTEX/cis-1,1-dichloroethylene (cis-DCE), BTEX/total petroleum hydrocarbons (TPH)/TCE, and toluene and ortho-xylene (ToX/TCE] was assessed under different environmental conditions (pH and temperature) by using indigenous microorganisms isolated from potentially contaminated regional sites. The highest TPH bioremoval efficiencies (<50%) occurred at 25°C and under neutral or alkaline conditions. TCE was cometabolized with toluene and o-xylene provided as growth substrates, and the highest bioremoval efficiency occurred at ToX/TCE, and pH and temperature impacted the mineralization of compounds. This study would help enhance the applicability of bioremediation technology to the mixed-wastes contaminated sites.