RPI - Remediation, LNAPL, DNAPL, Regenesis

NFA! A.G. Wassenaar Achieves Success at Colorado Car Dealership

I’ve been telling hundreds of versions of this same story with different names and locations for more than 14 years.  I never get tired of it!

The site is a former gas station that operated from 1959 until approximately 1978.  The property was purchased in 1984 and the underground storage tanks were removed in 1985.  A car dealership currently operates on the property.  While doing some geotechnical work in 2008, A.G. Wassenaar (AGW) personnel discovered Total Recoverable Petroleum Hydrocarbon (TRPH) concentrations which exceeded the State of Colorado action level.  The petroleum release was immediately reported to the Division of Oil and Public Safety (OPS) by the property owner.

Quarterly groundwater sampling was initiated in 2009.  In August of 2012, AGW undertook an aggressive Remediation Design Characterization (RDC) sampling effort to eventually support a Trap & Treat® BOS 200® treatment regime.  Numerous soil and groundwater samples were collected and analyzed at the RPI Group Project Support Laboratory at no charge.  Monitoring well splits were also analyzed by a local certified environmental laboratory.

In July of 2013, BOS 200® slurry injections were completed at 47 locations by Vironex (now Cascade Technical Services), an RPI Group Approved Installer.  Through June of 2014, benzene, toluene, ethylbenzene, and xylene (BTEX) concentrations exhibited significant reductions in the affected monitoring wells.  One of the six impacted monitoring wells exhibited an increase in BTEX concentrations and additional BOS 200® injections in that localized area were authorized by OPS and completed by the AGW team in August of 2014.  Fast-forwarding to March of 2016, 5 wells were non-detect (ND) for benzene and a sixth well had reduced to 7.8 ppb.  On June 21, 2016, OPS issued a No Further Action Determination.

Rachel Peterson, AGW’s project manager for this site, said “This has been a very interesting project from start to finish, and I’m so pleased that we were able to remediate the site in a timely manner with minimal interruption to our client’s business operations.  It was a great experience working with Cascade Technical Services, BOS 200® and the RPI Group Support Laboratory!”  For additional information, feel free to contact Rachel at petersonr@agwco.com.