Barry Swenson South Yard Property |
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November
2005 through February 2007
North American Transformer (NAT) previously owned
the South Yard property, which was formerly used
to store transformers filled with polychlorinated
biphenyls (PCBs), namely Aroclor 1254 and 1260. NAT sold the South Yard property
to Barry Swenson Builder. After subsequent Phase II ESAs, elevated concentrations
of PCBs were detected in subsurface soil up to 156 ppm. Over 16,000 cubic
yards of PCB-impacted soil was determined to contain elevated PCB concentrations
over 1 ppm. Barry Swenson Builder contracted with BioTech
Restorations to use our Factor in destroying elevated PCBs in
the soil prior to development of the South Yard facility. A Remedial
Action Plan (RAP) was prepared and submitted to the California Regional Water
Quality Control Board – Region 2 (Water Board) for review and was approved
in June 2005.
The Water Board was chosen as the lead agency to
oversee cleanup since they were the lead agency
on overseeing the  adjacent NAT cleanup. However,
on-going groundwater extraction and remediation
of a migrating volatile organic compounds (VOCs)
plume beneath the site from an off-site source
required the destruction of 13 groundwater monitoring
and extraction wells on the South Yard facility
through the Santa Clara Valley Water District (SCVWD). Upon completion
of well destruction activities, the PCB-impacted soil was encountered up to 6
feet below ground surface (bgs) and was excavated and spread over most of the
property in a 2-foot lift. In November 2005, approximately 90,000 pounds
of Factor, lime and other soil amendments were thoroughly mixed and irrigated
on site. The treated soil was routinely mixed (every 10 days) and irrigated
(up to 3 times a week) for 7 months. By June 2006, over 75% of the PCB-impacted
area at the site indicated PCB concentrations less than 1 ppm. By August
2006, over 90% of the PCB-impacted area at the site indicated PCB concentrations
less than 1 ppm. An additional 8,000 pounds of Factor, lime and soil amendments
were mixed into the residual elevated PCB area. By February 2007, 96% of
the property indicated PCB concentrations less than 1 ppm. Due to construction
requirements, BioTech Restorations agreed
to excavate and dispose approximately 575 cubic yards
of residual PCB-impacted soil at a Class II sanitary
landfill. The PCB concentrations in the disposed
soil did not exceed 4 ppm. The Closure Letter dated February 26, 2007 issued
by the Water Board indicated “no further action relating to the PCB
releases at the subject site is required. “
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