Brief

At an active gasoline retail station in Rio de Janeiro, historical spills of diesel residues resulted in groundwater impacts to the underlying sand aquifer. Compounds of concern included including benzene, toluene, ethylbenzene, and xylenes (BTEX), diesel residues, and naphthalene. ASR was retained by the facilities owner to address the impacted groundwater using an insitu remedial program with the objective of mass reduction and mitigating off site and human health risks. Part of the remedial plan involved minimizing the system footprint, energy requirements, and noise generation.

Process

The site owner along with their environmental consultant worked with ASR to develop a remedial work plan based on meeting the remedial objectives for the site. After reviewing the geology, hydrogeology and geochemistry of the site, ASR developed a plan that used aerobic bioremediation to address the dissolved phase impacts. The plan used direct push technology coupled with oxygen-releasing materials to facilitate the destruction of the BTEX and gasoline residues within the groundwater. Additional monitoring included compound specific isotope analysis (CSIA) along with detailed microbiological assessment of the aquifer.

Results

Over 65,000 kg of remedial solution being injected over a 2- week period at low pressure.

Reduction of diesel range concentrations greater than 98.4 percent for a two-year period

Injection program completed under budget and under schedule resulting in a 7 percent savings for client.

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