SVE REMEDIATION SYSTEM
DAYTON, OHIO

LBG designed and oversaw the installation of a SVE system consisting of 12 nested well locations to reduce the potential hazards associated with soil removal activities during construction activities at the site. The compounds of concern at the site are chlorinated solvents (PCE, TCE, TCA, DCE, DCA, and VC) and Freon. After approximately 150 days of operation the system removed 1,800 pounds of VOCs and reduced soil concentrations by 90 percent, thereby reducing the associated risk. By the end of second quarter 2000 an additional 42 nested well locations are scheduled to be installed. Over the course of remedial activities at the site, there is the potential to install an additional 30 nested well locations based on known historic operations at the site.

Originally, the SVE system was a short-term project in support of construction activities. LBG worked with the client to incorporate portions of a SVE system from another site into a small skid unit consisting of a liquid vapor separator and a regenerative blower. This system operates at approximately 600 scfm and 40 inches of water column. With the installation of an additional 42 nested well locations and a tight construction schedule to meet, LBG has recommended the procurement of a second SVE system.

The initial 12 nested well locations and the upcoming 42 nested well locations are all installed within the plant buildings, adjacent to active production lines. Well installation activities and wellhead design have taken into account these site constraints. The piping from the wellheads is routed up structural support I-beams and connected to the SVE headers along the facility roof line. All individual well monitoring ports are located at least 8-feet above the facility floor (inside the I-beam webbing) to prohibit tampering.

As the initial design called for a 3-month period of operation, granular activated carbon was selected as the most cost effective technology to achieve emission limits of 9 pounds of total VOCs per day. A heat exchanger was incorporated into the system design to increase the efficiency of the carbon.

As the plans expanded for the SVE system operation, the method of emission control was re-evaluated. It was demonstrated that catalytic oxidation and a scrubber would be more cost effective over the lifespan of the project. The carbon has been removed and a catox and scrubber has subsequently been added to the system.

Due to the presence of Freon in the air stream, a catalyst resistant to hydrofluoric acid has been included in the design of the catox.