ABSTRACT
Benzene, toluene, ethylbenzene, and xylene (BTEX) hydrocarbons are known to biodegrade under aerobic and anaerobic conditions in the subsurface. esearchers and professionals in the ground water industry have recognized the importance of biodegradation of BTEX for remediating hydrocarbon contaminated sites and have thus extensively studied intrinsic and enhanced bioremediation of these compounds. Enhanced bioremediation refers to engineered technologies that stimulate the indigenous microorganisms and accelerate their biodegradative capabilities. Researchers determined the subsurface readily supports active microbial populations that can biodegrade these soluble components in fuels. They also determined that the microbial biodegradation of BTEX is limited by the electron acceptor supply. Numerous protocols and models have been developed to aid in assessing the biodegradation potential at field sites and predicting future plume status with intrinsic bioremediation. Additionally, the first-order decay expression is only applicable when BTEX concentrations are much smaller than the half-saturation constant for the chemical.
