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Air Stripping and Soil Vapor Extraction as Site Remediation Measures
Published in Donald L. Wise, Debra J. Trantolo, Edward J. Cichon, Hilary I. Inyang, Ulrich Stottmeister, Remediation Engineering of Contaminated Soils, 2000
Constantine J. Gregory, Frederic C. Blanc
Soil vapor extraction (SVE), illustrated below, in Fig. 2, is a relatively new, in-situ remediation technique used to remove VOCs from contaminated subsoils in the vadose zone which lies above the groundwater table. The groundwater table may also be lowered by pumping, with or without the aid of subsurface slurry curtain wall containment barriers, to create an expanded vadose zone. The vapors, which are extracted in an air stream, are of ten passed through a treatment unit which removes or destroys the vapors before discharging the air. Included in the process train are containers in which moisture removed by the air stream can be condensed. In the typical case a number of subsurface extraction wells are constructed and connected by means of manifold piping which is connected to a vacuum system. As air flows through the soil to the extraction wells, volatile organics desorb from the soil particles as vapors which are carried by the air flow. Clean air enters the soil naturally or is introduced through a reverse venting system as the contaminated air is removed by the vapor extraction system. In some instances, impermeable barrier materials may be placed on the ground surface at site to limit short-circuiting of air flows through the system. For the soil vapor extraction system to be effective, the subsoils must have a high permeability. In such circumstances it offers a low-cost, easy-to-implement method of subsoil VOC removal which can be utilized at sites contaminated with gasoline, industrial solvents, and other volatile chemical substances.
Design of Soil Vapor Extraction Systems
Published in Jimmy H.C. Wong, Chin Hong Lim, Greg L. Nolen, Design of Remediation Systems, 2020
Jimmy H.C. Wong, Chin Hong Lim, Greg L. Nolen
Soil vapor extraction (SVE), also known as vacuum extraction, enhanced volatilization, in situ volatilization, soil venting, and in situ aeration, is a relatively low-cost and effective soil remediation technology for soils contaminated with volatile organic compounds (VOC) and petroleum hydrocarbons. A typical SVE system includes vapor extraction wells, blower, condensate separator (also known as knockout tank), control valves, pressure gauges, and flow meters. If vapor abatement is required, vapor treatment methods such as catalytic oxidation, thermal destruction, or carbon adsorption of extracted vapor can be employed. A simplified SVE system with vapor treatment is depicted in Figure 5.1.
Remediation
Published in Daniel T. Rogers, Urban Watersheds, 2020
Soil Vapor Extraction or SVE removes contaminants from the soil in the form of vapors from the soil above the water table. This technology is limited to those contaminants that can evaporate rather readily, such as VOCs. In addition, the geology must typically be composed of material that will permit the movement of air through the zone where the contaminants exist, such as sand or gravel. The vapors are typically captured whereby the contaminants in the air are removed before the air is discharged into the atmosphere. Figure 12.2 shows an example of an SVE system (Federal Remediation Technologies Roundtable 2019).
The effect of age on petroleum hydrocarbon contaminants in soil for bioventing remediation
Published in Bioremediation Journal, 2019
In situ techniques focus on remediating the soil on site and are often less expensive but more time consuming. One popular technique for the remediation of TPH is soil vapor extraction (SVE), which takes advantage of the high vapor pressure of the contaminants. This method uses a series of pumps and wells to increase the air circulation in the soil, stimulating the volatilization of the chemicals, which are then extracted with a vacuum (Wilson 1995). However, the effects of mass transfer resistance cause tailing and rebound, which can cause the treatment time to be extended, sometimes an entire order of magnitude longer, while also keeping the contaminant levels above clean-up levels (USEPA 1996).
Amendment additions and their potential effect on soil geotechnical properties: A perspective review
Published in Critical Reviews in Environmental Science and Technology, 2021
Fuming Liu, Shuping Yi, Wan-Huan Zhou, Yong-Zhan Chen, Ming Hung Wong
Semi-volatile organic compounds (SVOCs) and volatile organic compounds (VOCs) are two groups of organic contaminants that have been widely investigated for remediation. Most prominent investigations cover gasoline hydrocarbon, gasoline oxygenate, refrigerant, solvent, and trihalomethane, contributing to the fountainhead of vapor intrusion (Birn & Boerge, 2017). Technologies used for the remediation of sites contaminated with (S)VOCs generally involve thermal desorption, soil vapor extraction (SVE), permeable reactive barriers, bioremediation and biodegradation, air sparging/soil vapor extraction, pervaporation, soil washing/flushing solutions, advanced oxidation process (AOP), bioelectrokinetic remediation, and nanoremediation. Some of these technologies are designed based on their low-boiling point, which compels large numbers of molecules to be evaporated or sublimated on the liquid-gas interface. Typical technologies range from thermal desorption to soil vapor extraction (SVE), air sparging/soil vapor extraction, and pervaporation. These technologies belong to physical remediation technologies and aim to uptake/remove (S)VOCs by improving their mobility in soil through diffusion or advection of the vapor, aqueous, or non-aqueous phase liquid (NAPL) and ultimately collecting and treating them on the ground before they are released into the atmosphere (Paumier, Touzefoltz, Mazeas, & Guenne, 2018). The efficiency of (S)VOC removal technologies is most apparent in cases where the unsaturated zone in the contaminated site is relatively permeable and homogeneous (Hinchee, Dahlen, Johnson, & Burris, 2018). Furthermore, it is important to conduct a relatively comprehensive assessment of the site, including groundwater conditions, hydraulic properties, site geology of the main geological layers or 3D structures, distribution characteristics, and dimensions of contaminant plumes in the soil and groundwater prior to the implementation of remediation (Nambi, Rajasekhar, Loganathan, & RaviKrishna, 2017). Incineration is a relatively forcible approach for the cleanup of (S)VOCs. It is mainly applied as an ex situ remediation method that is coupled with excavation and off-site disposal technologies. However, hazardous gas release problems limit its application.