Completed Project
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| Contaminants of Concern: | PCE and Xylene |
| Starting Contaminant Levels: | DNAPL, LNAPL |
| Depth of Remediation: | 30 feet bgs |
| Geology: | Landfill debris (buried drums), silty clay |
| Hydrology: | Groundwater at about 15 feet bgs |
| Remediation Design Engineers: | Mr. Greg Beyke, Mr. Jerry Wolf |
| Operations Manager: | Mr. Jerry Wolf |
| Project Manager: | Mr. Tom Powell |
| Current Project Status: | Full-scale operations completed in South Pit |
| Scheduled Completion Date: | December 2002 |
TRS was selected to provide full-scale ERH at the Lowry Landfill Superfund site. The full-scale ERH system including over 100 electrodes with co-located vapor recovery wells were installed in the south waste pit of the Lowry Landfill in 2001-02. Full-scale operations in the south waste pit began in mid April 2002 and were completed in December 2002.
The remedy at the Lowry Landfill consists of ERH combined with Multi-Phase Extraction (MPE) for maximum recovery of PCE DNAPL and Xylene LNAPL. The recovered vapors at the surface are being treated with a flameless thermal oxidizer. Recovered liquids are shipped offsite for incineration.
The site is being remediated in two phases. The first phase is remediation of the south waste pit. Depending on the results of remediation in the south waste pit TRS will move the ERH system to the north waste pit. Both pits are about 1 acre each in area.
The landfill contains a large amount of metallic debris in the form of buried 55-gallon drums and miscellaneous metal including automobile bodies and mattress springs. There is also wood debris, car tires, and municipal waste in the Landfill. A plenum consisting of a layer of gravel covered by a clay cap is at the surface. The soil lithology consists of clay, silt, sand and bedrock with groundwater at approximately 20 feet bgs. The heating interval is between 9 ft and 24 ft bgs. The heating strategy consists of establishing a hot floor in the lower heated interval and sweeping the heat up toward the top of the interval in two phases capturing vapors, steam and liquids at the surface.
The ERH & MPE system in the south waste pit consists of 107 electrodes, 7 multi-phase extraction wells, 18 multi-phase (soil, gas, and liquid) monitoring points, 7 vapor monitoring points in the gravel layer of the plenum, and 105 temperature monitoring points (TMPs). TRS began heating in the south waste pit on March 29, 2002. The performance criteria established for this project include heating the treatment interval to an average 90ºC for 120 days, maintain vapor capture and control of ambient air emissions, and reduce Xylene concentrations by 90%. The goals were met in the south waste pit and ERH operations are complete. The ERH system may be moved to the north waste pit in 2003.
Monitoring of fluids and vapors at the surface as well as subsurface pressure and vacuum are performed routinely to verify that the ERH system is operating optimally.
Figure 1. Site Layout at the Lowry Landfill
TRS began heating in the South Waste Pit in April 2002. Following four months of ERH and MPE operations the design temperature (>75°C) was met. Heating in the South Waste Pit was completed at the end of 2002. Greater than 15,000 kgs of total VOCs were recovered representing more than a 70% average reduction in total VOCs. Greater than 4,000 kgs of total Xylenes were recovered representing more than a 80% average reduction in total Xylenes. During the ERH and MPE operations in the South Waste Pit approximately 2,500,000 kW-hrs of electricity were input into the subsurface during the remediation. The client is presently considering moving the ERH and MPE system to the North Waste Pit for remediation of PCE DNAPL.
Figure 2. Multi-Phase Extraction Wellhead
Figure 3. Electrode & Co-located VR Well