Enhanced natural attenuation of C999 in groundwater using bio-barrier, 2. Subsurface microorganism change and dechlorination mechanism

Abstract

As the enhanced natural attenuation (E NA) technique of chlorinated aliphatic hydrocarbons (CAHs) in groundwater, a bio-barrier was installed in aquifer by injecting the hydrogen release compounds. Long term monitoring was conducted for 3 years to evaluate the effectiveness of the technology, and biological tests have been continuously conducted to measure the change of subsurface biological environment. After bio-barrier installation, microbial community structure in the groundwater had been obviously changed.β-subclass and γ-subclass of Proteobacteria was dominant. As time passed, changes in the microbial community structure and dominant species were observed. Degradation of CAHs was observed regardless of the change in the detection situation of Dehalococcoides sp., and so it was presumed that another bacteria was related to the degradation of CAHs.