Tetra Tech conducted a groundwater study to evaluate the effectiveness of ongoing remediation of volatile organic compounds in groundwater on behalf of an industrial chemical client in Campinas, Brazil.

The client is using in situ chemical oxidation (ISCO) to treat elevated concentrations of 1,2-dichloroethane, cis-1,2-dichloroethene, vinyl chloride, dichloromethane, and trans-1,2-dichloroethene in soils and groundwater at a former chemical waste dump site.

Tetra Tech identified anomalies in groundwater contaminant concentrations within ISCO treatment areas. Our team recommended construction of an underground permeable reactive barrier (PRB) using injections of reactive materials spaced to form overlapping radii of influence, thereby creating an additional treatment zone to address these rebounds.

Tetra Tech’s team conducted the groundwater monitoring study and a pilot test to select an optimal remedial technology. We designed the PRB and injected malt extract through existing injection wells to create the PRB in the contamination plume’s center of mass. Tetra Tech also conducted groundwater monitoring to evaluate the effectiveness and efficiency of PRB treatment after full-scale injection of the malt extract, showing that concentrations are decreasing as expected. In addition, the PRB contains and treats any contaminant rebounds during ongoing in situ chemical oxidation remediation also underway at the site.

Project activities were conducted in accordance with regulations for management of contaminated areas (CETESB / GTZ 2001) and applicable environmental standards.