Former Ferg's Market

Soil and Groundwater Remediation

Sierra West conducted groundwater investigations and pilot studies, prepared a feasibility study and final remedy design, and constructed environmental remediation systems for MTBE impacted groundwater and soil. Impacted groundwater was detected in two of five water bearing geologic zones and migration occurred in two distinct directions. A nearby municipal water supply well was impacted by MTBE, thereby increasing the urgency of developing a suitable environmental remediation solution at a site with ongoing litigation between oil companies, the former property owner, and the local water supply company. Environmental oversight transitioned from Sacramento County to a Cleanup and Abatement Order issued by the Central Valley Regional Water Quality Control Board (RWQCB).

Groundwater extraction/aquifer tests, air sparging tests, and in-situ ozone oxidation pilot tests were conducted prior to preparing the feasibility study and implementing the final treatment solution. A soil vapor extraction system was operated and then shutdown. A groundwater extraction and treatment system and an in-situ ozone injection system were installed at the source area, operated, and then relocated downgradient. Source area MTBE concentrations decreased from 10,000 ug/L to non-detect after a year of operation. Downgradient MTBE concentrations decreased from 5,000 ug/L to non-detect in a similar time period. Once considered a high priority site, the remediation is complete and the Site has been closed by the RWQCB.

Project Relevance

Sierra West resolved technical issues with respect to complex hydrogeology, recalcitrant chemicals, an impacted water supply well, multiple migration directions, and construction in an active urban setting. In addition, political issues were resolved with respect to: litigious circumstances, property access for off-property investigations and remediation system construction; and changing oversight agencies.