Confidential Benzene Site

Project Summary

A historical release from an underground transfer line resulted in benzene soil and groundwater impacts over an approximately 1 mile in length along an active utility corridor. The geology consisted of tight weathered clays and sandy clay and depth to groundwater ranging from 4 to 5 feet below ground surface (ft bgs). A low hydraulic gradient and the underground utility corridor presented remedial challenges for traditional methodologies.

The client previously conducted various in-situ pilot studies to evaluate feasible and effective remedial options including traditional ISCO amendments and multi-phase extraction (MPE). Only limited efficacy was observed with these remedial options.

Remedial Plan

A pilot-scale application was designed to address soil and groundwater benzene impacts using Provect-EBR®. This technology is a subsurface, electrokinetic system that continually generates controlled Fenton's-like reactive oxygen species and dissolved oxygen without the addition of chemicals. The system integrates in-situ chemical oxidation (ISCO), microbiological, and geophysical mechanisms without altering pH or generating any bioproducts.

Four (4) Provect-EBR® well reactor and electrode sets were installed, surrounded by monitoring wells to continuously collect real-time geochemical data within and adjacent to the treatment area.

Results

• pH values remained stable and ORP values transitioned from reducing to significantly oxidizing conditions (e.g., 400 to 700 mV).
• An approximate 15–20 ft radius of influence (ROI) was obtained.
• Single reactor sets per well were determined to be sufficient.
• Following system shutdown, groundwater results indicated 60 to >90% benzene reductions from surrounding sampling locations.
• Estimated power consumption of $4 to $9 per day operational cost — significantly less than other previously evaluated alternative remedies.