Chlorinated organic compounds groundwater

Dense nonaqueous phase liquids (DNAPLs) are the chlorinated organic compounds that have a density higher than water. Because of this unique property, DNAPLs will pass through the vadose zone and contaminate groundwater. Some reside in... 

Table IX. First-Order Rate Constants for Removal/Destmction of Chlorinated Organic Compounds from Groundwater Using Sonication Alone, Vapor Stripping Alone, and Combined SonicationA apor...

Name two industrial products whose manufacture introduces chlorinated organic compounds into groundwater. 

Unlike petroleum hydrocarbons, organic compounds in general followed a different evolutionary path. Chlorinated solvents are a common group of organic compounds, and are also the most frequently encountered contaminant in groundwater. Common industrial chemicals that are characterized as chlorinated solvents include trichloro-ethene (TCE), 1,1,1-trichloroethane (TCA), tetrachloroethene (PCE) or perchloro-ethylene, chlorofluorocarbon (Freon)-113 (i.e., 1,1,2-trichloroethane or 1,2,2-tri-fluoroethane), and methylene chloride. In 1997, the EPA reported the presence of TCE and PCE in 852 of 945 groundwater supply systems throughout the United States and in 771 of 1420 Superfund sites. 

Dowex Optipore is a polymeric adsorbent used to treat chlorinated volatile organic compound (CVOC) contaminated off-gas streams from remediation processes such as air stripping of groundwater and soil vapor extraction. According to the vendor Dowex Optipore adsorbent has the following advantages over activated carbon ... 

CESAR was developed to address the problem of locating, characterizing, and removing dense non-aqueous-phase liquids (DNAPLs) from contaminated aquifer systems. The process is particularly suited to remediating groundwater contaminated with chlorinated solvents, such as trichloroethylene (TCE), tetrachloroethene (PCE), trichloroethane (TCE), and carbon tetrachloride (CCE). According to the vendor, CESAR can also be applied to sites contaminated with creosote, polychlorinated biphenyls (PCBs), Freon 113, volatile organic compounds (VOCs),... 

The two-zone plume interception treatment technology is designed to treat chlorinated and nonchlorinated organic compounds in groundwater using a sequence of anaerobic and aerobic conditions. The in situ technology has been applied to aquifers contaminated with benzene, toluene, ethylbenzene, and xylenes (BTEX) petroleum products hydrocarbons coal tar wastes and industrial feedstock chemicals. The technology does not treat metals. 

Natural attenuation, often called intrinsic remediation, intrinsic bioremediation, bioattenuation, or monitored natural attenuation (MNA) is an in situ treatment technology for soil, sediment, or groundwater. The technology has been used for full-scale remediation of sites contaminated with volatile organic compounds (VOCs), total petroleum hydrocarbons (TPH), chlorinated solvents, explosives, inorganics, and metals. 

In situ thermal extraction is a process for the removal of volatile and semivolatile organic compounds (VOCs and SVOCs) from contaminated soils and groundwater. The process primarily treats chlorinated solvents such as trichloroethylene (TCE), tetraehloroethylene (PCE), and dichlorobenzene hydrocarbons such as gasoline, diesel, and jet fuel and mixtures of these compounds. 

Terra Systems, Inc. s, in situ bioremediation (ISB) technology can treat hydrocarbons and some chlorinated volatile organic compounds (VOCs) present in soil and groundwater. Many soils... 

The type of activated carbon used for the treatment of groundwater depends upon the other organic compounds present. For example, humic acids will often compete with other contaminants for adsorption sites. Hence, for each situation, isotherms should be determined, and the efficiency of contaminant removal should be evaluated on a TOC basis (total organic carbon). As noted, the compounds most prevalent in groundwaters are chlorinated organics. Their removal by adsorption on GAC is the most effective treatment in liquid or gas phase processes [66]. 

Zero-valent iron (ZVI) barriers are a specific application of reductive precipitation that recently have been utilized for removing low concentrations of some halogenated organic compounds from waste or run-off streams. Interestingly enough, ZVI, which functions at ambient temperature and near neutral pH values, has been found to decompose chlorinated compounds by a reductive mechanism in the absence of air and by an oxidative one in its presence." In the latter case, the ZVI actually catalyzes the formation of the hydroxyl radical, a very potent oxidant. Attention has been placed recently on the use of nano-sized ZVI for in-situ remediation of soils and groundwater." ... 

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