Evaluating the effects of electron donor delivery for the treatment of a chlorinated DNAPL source zone

A controlled pilot scale aquifer system known as the Experimental Controlled Release System (ECRS) was used to evaluate the bioremediation of PCE DNAPL source zones. The addition of DNAPL in the ECRS made a thorough hydrologic evaluation of the system both more essential and problematic. The focus of this research was to develop a detailed site characterization to help ensure the effective delivery of electron donor (Hydrogen Releasing Compound) and microbes for dechlorination of PCE. Transient water level monitoring, tracer tests, MODFLOW models and spatial analyses of aqueous samples were used to define the hydrogeology of the ECRS. Results of these experiments found that addition of the above constituents resulted in no overall aquifer clogging or impacts on the hydraulics. Additional findings of this investigation contradict some previous laboratory studies with regard to the influence of methanogens on dechlorination and methane production, which is believed to result in aquifer clogging.