Soil vapor extraction system

Poppendieck, D.G., Loehr, R.C. and Webster, M.T., Predicting hydrocarbon removal from thermally enhanced soil vapor extraction systems. 2. Field study, J. Hazard. Mater., 69, 95-109, 1999. 

Conceptual Design for the Soil Vapor Extraction System... 

For another site in Regina in 1995, a total cost for 11 fractured wells, two soil vapor extraction systems, and operation and maintenance for 6 months was approximately 80,000. This figure did not include vapor treatment since none was required. Colder estimated that, had hydraulic... 

NEPCCO SoilPurge soil vapor extraction systems are noncontacting, oil-free, explosion-proof vacuum systems designed to remove volatile organic compounds (VOCs) from soil in situ. According to the vendor, benzene, toluene, ethylbenzene, and xylenes (BTEX), chlorinated solvents and other hydrocarbons can be treated with SoilPurge systems. The technology can also remove radon from soil. 

According to the vendor, the SoilPurge soil vapor extraction systems are constructed for one-person installation, are skid mounted, have a total height of less than 4 ft, and are available in footprints starting at 36 inches by 30 inches. 

The MVS technology is commercially available and was used to remediate soil contaminated with VOCs from a leaking underground storage tank at a Superfund site in upstate New York. The MVS technology was selected to remediate this site over bio venting and soil vapor extraction systems. 

In 1999, HRC was used with other treatment technologies at a brownfield site in Aurora, Colorado. An in situ air sparge/soil vapor extraction system was first used at the site to treat TCE contamination however, additional measures were needed to prevent the migration of PCE off-site. After an unsuccessful application of zero-valent iron injection, 240 lb of HRC were injected at five locations by direct-push methods. Total project costs were 110,000, which... 

State of Technology Review Soil Vapor Extraction Systems U.S. Environmental Protection Agency, 1989, EPA/600/2-89AI24. 

Hutzler, N. J., Murphy, B. E., and Gierke, J. S. (1989). State of Technology, Review Soil Vapor Extraction Systems, USEPA Risk Reduction Engineering Lab, Cincinnati, OH. 

A major advantage of air sparging is that it requires only simple materials to constmct a field system. No special equipment needs to be designed and all equipment used is easily obtained. Equipment required for the air injection system and soil vapor extraction system is summarized in this section. 

Details of soil vapor extraction system, including vacuum, spacing and depth. 

Soil Vapor Extraction System. Once the air is injected into the saturated subsurface, it wiU migrate toward the surface due to the effect of buoyancy. Eventually the contaminated injected air will enter the vadose zone. At this point, a sou vapor extraction (SVE) system may be implemented. Soil vapor extraction applies a vacuum to the vadose zone to assist in collecting vapors. The vacuum will help vapor collection as well as assist in preventing unwanted off-site migration. Equipment used in a soil vapor extraction system is similar to that used in an air sparging system, except that a vacuum pump is used instead of an air compressor. Additionally, if the vapors being collected by the soil vapor extraction system are moist, a dewatering system may be employed (Johnson et al., 1993). 

Flow Rate/Mode of Injection. Once the type of gas to be injected is determined, the flow rate and mode of injection must be determined. Loden (1992) reported that flow rates of 2 to 16.5 scfm are typical for field application. Nyer and Suthersan (1993) reported that when soil vapor extraction systems are used at a site, injection flow rates between 4 and 10 scfm are used. It has been reported that any flow rates beyond contaminant diffusion kinetics are a waste of effort (Roberts and Wilson, 1993 Reddy and Adams, 1999 Adams and Reddy, 1999). Additionally, Rutherford and Johnson (1996) found that oxygen transfer into ground-water may actually be impeded by an injection flow rate that is high because the air wUl act to push the groundwater away from the point of injection, decreasing interfacial transfer area and oxygen transfer. 

Gordon, M. J. 1998. Case History of a Large-Scale Air Sparging Soil Vapor Extraction System for Remediation of Chlorinated Volatile Organic Compounds in Ground Water, Groundwater Monitoring and Remediation, vol. 18, no. 2, pp. 137-149. 

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