LACO investigated and remediated impacts to soil and groundwater originating from five underground storage tanks, pump islands, and associated piping, which were removed in 1991. The project site had been operating as a service station since the 1950’s. The constituents of concern (COCs) at the site included total petroleum hydrocarbons as gasoline (TPHg) and diesel (TPHd), MTBE, benzene, toluene, ethylbenzene, and xylenes (BTEX). This site is located on Highway 101, in a residential and commercial area.
Our project team installed an in-situ chemical oxidation (ISCO) system that included ozone sparging under the Underground Storage Tank Cleanup Fund’s Pay-for-Performance program. This remediation system enabled LACO to reduce the concentration of TPHg, TPHd, and BTEX COCs at the site from base line values to active remedial target values by 100%. In order to address the offsite MTBE plume, our team installed offsite sparge wells and operated our mobile remediation unit (MRU) for a duration of five days. MTBE concentrations declined from pre-cleanup levels, and our client received a “No Further Action Letter” in November 2012.
