Brief

At an active industrial facility, historical spills of the chlorinated ethenes trichloroethene (TCE), resulted groundwater impacts to a fractured rock aquifer. Pump & treat remedial efforts by others were unsuccess at reducing the TCE and its dechlorination daughter products cis 1,2 dichloroethene, and vinyl chloride to acceptable concentrations. ASR was retained by the site owner to develop an insitu remedial work plan that used chemical reduction and anaerobic bioremediation to address the dissolved phased plume. The remedial plan used focused low pressure, low volume injection techniques to deliver the remedial regents to the injected plume.

Process

The owner of the industrial facility along with the owner’s consultants worked with ASR to develop a remedial work plan that included installing multilevel wells and packer systesm to better define the impacts and transport pathways. The updated conceptual site model (CSM) allowed ASR to develop a remedial plan that used chemical reduction and anaerobic bioremediation to reduce the contaminant mass within the aquifer to below the regulatory limits and eliminate risks to humans and the environment as well as limit liability associated with off site migration. The remedial plan was based on injecting a mixture of organic donors including fast and slow-release organic carbon along with micro and nano zero-valent iron to address any potential back and matrix diffusion issues.

Results

Over 69,000 kg of remedial solution being injected over a 3- week period at low pressure

Reduction of TCE concentrations of greater than 99.99 percent for a three-year period

Reduction of 1,2 DCE concentrations greater than 99.99 percent for a three-year period

Reduction of vinyl chloride concentrations greater than 99.99 percent for a three-year period

View More Details