Pump and Treat with Air Stripping
- Extraction system consists of 13 recovery wells installed across the width of the initial contaminant plume
- Treatment includes an equalization/neutralization tank followed by an air stripping tower
- A network of 41 monitoring wells and 13 recovery wells are used to monitor quarterly changes in groundwater quality
- The actual average pumping rate for the system has been 195 gpm
- ROD Date: 3/29/90
|EPA Point of Contact:|
Pam Scully, RPM
U.S. EPA Region 4
345 Courtland St., N.E.
Atlanta, GA 30365
|State Point of Contact:|
Florida DEP (FDEP)
Twin Towers Office Bldg.
2600 Blair Stone Road
Tallahassee, FL 32301
Chlorinated solvents and BTEX
- Initial contaminants of concern included 1,1,1-DCA, 1,1-DCE, methylene chloride, vinyl chloride, PCE, TCE, 1,1,1-TCA, benzene, toluene, ethylbenzene, acetone, MEK, MIBK, and phthalates
- Maximum concentrations detected in 1988 included 1,1-DCE (6,000 mcg/L), acetone (146,000 mcg/L), and MIBK (78,000 mcg/L)
Improper disposal practices and unauthorized dumping
Type/Quantity of Media Treated:
- 151.7 million gallons treated as of May 1997
- No NAPL have been observed in monitoring wells on site
- Extraction wells are located in one aquifer at the site
- Hydraulic conductivity reported as 6.3936 ft/day
Purpose/Significance of Application:
The hydrogeology at this site is relatively simple and hydraulic conductivity relatively high, conditions which should lead to a successful application for pump and treat technology.
Regulatory Requirements/Cleanup Goals:
- Cleanup goals are to remediate groundwater to levels set by the FDEP for the following constituents: acetone (700 mcg/L), benzene (1 mcg/L), 1,1-DCA (5 mcg/L), 1,1-DCE (7 mcg/L), cis-1,2-DCE (70 mcg/L), trans-1,2-DCE (70 mcg/L), ethylbenzene (700 mcg/L), methylene chloride (5 mcg/L), MEK (200 mcg/L), MIBK (350 mcg/L), PCE (3 mcg/L), toluene (2,000 mcg/L), 1,1,1-TCA (200 mcg/L), TCE (3 mcg/L), total phthalates (3 mcg/L), and vinyl chloride (1 mcg/L).
- The primary goal of the system is to achieve hydraulic containment of the plume.
- From May 1994 through May 1997, total concentrations of contaminants have been reduced 86% from 3,121 to 444 mcg/L. However, concentrations of all VOCs remain above cleanup goals. In addition, concentrations of acetone, 1,1-DCE, and MIBK remain at persistently elevated concentrations. Through May 1997, approximately 2,700 pounds of contaminants have been removed from the groundwater.
- No contaminants have been detected in down-gradient monitoring wells since the beginning of remedial operations, and the plume has been contained.
Estimated costs for pump and treat were $1,674,800 ($1,094,800 in capital and $580,000 in O&M), which correspond to $10.60 per 1,000 gallons of groundwater extracted and $590 per pound of contaminant removed.
The City Industries site operated as a hazardous waste Treatment, Storage, and Disposal Facility (TSDF) from 1971 until 1983. From 1981 through 1983, EPA and county officials cited the facility for multiple violations of RCRA. In 1983, EPA, FDEP, and the county ordered the business to close, and the owner of the site abandoned the property. FDEP completed a multi-phased remedial investigation in May 1986. The site was listed on the NPL in March 1989 and a ROD was signed in March 1990.
The extraction system used at the site consists of 13 recovery wells installed across the width of the initial contaminant plume. Treatment includes an equalization/neutralization tank followed by an air stripping tower. Total concentrations of VOCs have declined 86% at this site, but remain above cleanup levels. The hydrogeology at this site is relatively simple and hydraulic conductivity relatively high, conditions which should lead to a successful application for pump and treat technology. According to the RPM, contaminant levels at the site in late 1997 and 1998 are lower than shown in the May 1997 monitoring data.