Topock Compressor Station

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PG&E is committed to addressing environmental issues resulting from our historical operationsat the Topock Compressor Station. Below you will find information about our remediation efforts. More information can be found on the California Department of Toxic Substances Control (DTSC) Topock project website.

Groundwater Cleanup

Currently, PG&E is in the process of developing a plan, called the “Remedy Design,” to clean up the groundwater.

The groundwater cleanup method has been selected by federal and state regulators. It is well-proven, thoroughly tested technology known as “In-situ Treatment with Fresh Water Flushing.”

The in-situ process starts by injecting a food-grade material (such as grain alcohol) into affected groundwater to stimulate the growth of naturally occurring bacteria within
the soil.

The growth cycle of the bacteria creates conditions that convert hexavalent chromium to trivalent chromium, a naturally abundant substance.

Once converted, trivalent chromium leaves the groundwater and becomes part of the surrounding soil. This cleanup technology has been used at numerous sites throughout the United States.

Soils Cleanup Plan

PG&E is also working with DTSC and DOI in planning work to further investigate soils at the compressor station. The work plan is currently undergoing regulatory review.

DTSC will be preparing a draft Environmental Impact Report (EIR) for public comments prior to the investigative work. Circulation of the draft EIR is anticipated in late 2013.

Click here  (PDF, 178 KB)to see a full schedule for the soils investigation.

Project Timeline

The “Remedy Design” plan is in the intermediate stage, known as the 60% Design. On April 5, 2013, the 60% Design was submitted to the oversight agencies. It will be reviewed by the agencies, tribes and interested stakeholders and their feedback will help refine the cleanup design.
Following the 60% Design, the plan will enter the pre-final stage, known as the 90% Design. Construction of the remedy components is scheduled to begin in late 2014.

Click here (PDF, 91 KB) to see a full schedule for the groundwater cleanup.

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