A company located in Redding has an aboveground fuel storage and retail fueling facility where remedial activities had been attempted unsuccessfully since 1990. VESTRA was contracted in 2005 to complete remedial activities at the site. VESTRA developed a strategic plan to address concerns and objectives and obtain information required to implement remedial action.

VESTRA developed a three-phased approach, including reducing offsite migration of dissolved phase contaminants, implementing source zone remediation, and collecting data to show natural attenuation processes will address remaining contaminants. The first phase involved a unique remedial design, which used a modified permeable reactive wall, incorporating ex-situ chemical oxidation (Klozur OBC, Sodium Persulfate mixture), soil flushing, and enhanced bioremediation.

VESTRA conducted a limited site investigation that included installation, sampling, and design of 12 soil borings, nine injection/extractions wells, and three groundwater monitoring wells. VESTRA summarized results of the investigation in a Report of Findings and subsequently reported and evaluated physical and chemical data in a Remedial Design Plan that was submitted to the Regional Water Quality Control Board.

The Remedial Design Plan was approved, and the remedial system was constructed in early 2007. Since then, a groundwater monitoring and pilot study have been conducted to evaluate potential for any adverse effects as well as the effectiveness of the system, and monitoring will continue to evaluate full-scale application.