Praxair South San Franscisco, CA – Turnkey Soil and Ground Water Remediation
Turnkey remediation of a large, complex industrial site with multiple contaminants – acetone, gasoline, benzene, toluene, ethylbenzene and xylenes – and challenging geology. Enpro managed the project, engineering and regulatory strategy over the project lifecycle, including site investigations; fate & transport modeling, feasibility/treatability studies and engineering; risk assessments, remedial action plans; remediation system design, air and water discharge permitting, operation & maintenance (O&M), ground water monitoring, decommissioning, and ultimate closure.
In earlier phases, Enpro's team implemented soil excavation (200 yards) and offsite disposal; soil vapor extraction (SVE) with catalytic/thermal oxidation, ground water extraction (2 million gallons) and treatment by air stripping and carbon adsorption, and dual-phase extraction removing over 37,000 pounds of acetone and petroleum from ground water and soil. We also decommissioned pump & treat/SVE remediation system after technical limits were reached, and then monitored natural attenuation.
In 2010 we designed and built a Peroxone (ozone and hydrogen peroxide) chemical oxidation system at this site. Ozone, oxygen and hydrogen peroxide were injected to chemically treat groundwater in situ. The contaminants include very high concentrations of acetone and much lower concentrations of petroleum hydrocarbons. The only emissions from this sustainable process are ozone (which breaks down into oxygen), oxygen and air. Dissolved acetone and petroleum hydrocarbons in the ground water react with the ozone, oxygen and hydrogen peroxide and are ultimately mineralized (broken down) into carbon dioxide and water. The carbon dioxide thus generated is in parts per million concentrations and dissolves in the ground water.