Brief

At an active industrial facility in Guarulhos, historical spills of the chlorinated ethene trichloroethene (TCE) resulted in impacts to the underlying shallow silty sand unconfined aquifer. Dechlorination of the TCE lead to additional impacts to the aquifer from , cis 1,2 dichloroethene, and vinyl chloride. Historical pump & treat operations were unsuccessful at remediating the plume thus the client was looking for alternative treatment methods. ASR in conjunction with the client’s consultant developed a remedial work plan that used anaerobic bioremediation to address the dissolved phased chlorinated ethenes. ASR's remedial plan used direct push technology to effectively deliver the reagents to the impacted aquifer.

Process

The owners of the industrial facility along with the owner’s consultants worked with ASR to develop a remedial work plan that included additional high-resolution characterization of the impacted aquifer that led to significant cost savings for the remedial program. The program included membrane interface probing, compound specific isotopes and DNA analyses of the aquifer system. Based on the updated conceptual site model (CSM) ASR was able to work with the consultant and client to develop a remedial plan that used 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 688,000 kg of remedial solution being injected over a 10- 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

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