Alternatives for controlling organics in groundwater supplies

Dyksen, John E.; Hess, Alan F.

doi:10.1002/j.1551-8833.1982.tb04954.x

Cited by 32 publications

(16 citation statements)

References 3 publications

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“…TCE is ranked 16th of 275 chemicals on the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) Priority List of Hazardous Substances for 2003 (ATSDR, 2003), a prioritization of substances based on a combination of frequency, toxicity, and potential for human exposure at Superfund National Priority List sites. TCE has been reported to be the most frequently detected organic solvent in U.S. groundwater and the solvent present in highest concentrations (Dyksen and Hess, 1982). TCE was detected in 91 of 945 drinking water samples collected in 1981 and 1982 by the U.S. Environmental Protection Agency (EPA) in a national survey of water systems that used groundwater sources (Westrick et al, 1984).…”

Section: Introductionmentioning

confidence: 99%

Trichloroethylene and dichloroethylene: A critical review of teratogenicity

Hardin¹,

Kelman²,

Brent

2005

Birth Defects Research

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Trichloroethylene (TCE) and dichloroethylene (DCE) are high-volume industrial chemicals frequently found as contaminants in public drinking water supplies. The developmental toxicity of both chemicals has been evaluated in laboratory and epidemiologic studies. It has been suggested that TCE and DCE are specific cardiac teratogens and that drinking water contaminated with them increases the risk of congenital heart defects in exposed human populations. In contrast, other laboratory and epidemiologic studies do not find an increase in developmental effects, either in general or specifically affecting the heart. This laboratory and epidemiologic base was reviewed to evaluate the strengths and weaknesses of the conflicting published reports. We conclude that the weight of experimental and epidemiologic evidence does not support the hypothesis that TCE or DCE is a selective developmental toxicant in general or a cardiac teratogen specifically.

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Section: Introductionmentioning

confidence: 99%

Trichloroethylene and dichloroethylene: A critical review of teratogenicity

Hardin¹,

Kelman²,

Brent

2005

Birth Defects Research

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“…Groundwater contamination by chlorinated hydrocarbons is a major problem throughout the United States (Dyksen and Hess, 1982;Vogel et al, 1987). In particular, the chlorinated hydrocarbons tetrachloroethene (PCE) and trichloroethene (TCE) are of concern.…”

Section: Introductionmentioning

confidence: 99%

“…These compounds have been used as degreasing agents, in the production of silicon wafers, in the dry cleaning industry, and in household cleaning products (Love and Eilers, 1982;Vogel et al, 1987). Due to their widespread use and because of poor handling and disposal practices, these compounds are frequently found as contaminants in groundwater (Dyksen and Hess, 1982;Vogel et al, 1987). TCE is the most frequently detected groundwater contaminant among the chlorinated hydrocarbons (Lee et al, 1988).…”

Section: Introductionmentioning

confidence: 99%

Reductive dechlorination of chlorinated ethene DNAPLs by a culture enriched from contaminated groundwater

Nielsen

Keasling

1999

Biotechnol. Bioeng.

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A microbial culture enriched from a trichloroethene‐contaminated groundwater aquifer reductively dechlorinated trichloroethene (TCE) and tetrachloroethene (PCE) to ethene. Initial PCE dechlorination rate studies indicated a first‐order dependence with respect to substrate at low PCE concentrations, and a zero‐order dependence at high concentrations. Studies of TCE and vinyl chloride (VC) dechlorination indicated a first‐order dependence at all substrate concentrations. VC had little or no effect on the initial rate of TCE dechlorination. With subsaturating concentrations of chlorinated ethenes, nearly stoichiometric amounts of the toxic intermediate vinyl chloride accumulated prior to its dechlorination to ethene. In contrast, under saturating conditions, in which a dense, nonaqueous‐phase liquid existed in equilibrium with the aqueous phase, the chlorinated ethene was dechlorinated to ethene, at a rapid rate, with the accumulation of relatively small amounts of chlorinated intermediates. © 1999 John Wiley & Sons, Inc. Biotechnol Bioeng 62: 160–165, 1999.

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“…This is likely due to chain reactions that are propagated by chlorine radicals. [7][8][9] Because the photocatalytic reaction occurs with greater efficiency and because chlorinated ethylenes are commonly found at contaminated sites, 10 trichloroethylene (TCE) and perchloroethylene (PCE) are often chosen as representative pollutants for PCO tests. Approximately 90% of Superfund sites have TCE or PCE as pollutants.…”

Section: Introductionmentioning

confidence: 99%

Pilot-Scale Demonstration of an Innovative Treatment for Vapor Emissions

Watt

Magrini

Carlson

et al. 1999

Journal of the Air & Waste Management Association

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Researchers from the National Renewable Energy Laboratory recently conducted a pilot-scale study at McClellan Air Force Base (AFB) in Sacramento, CA. The objective of the test was to determine the effectiveness of an ambient-temperature, solar-powered photocatalytic oxidation treatment unit for destroying emissions of chlorinated organic compounds from an air stripper. This paper reports test results and discusses applications and limitations of the technology.A 10-standard-cubic-foot-per-minute (SCFM) (28.3 L/min) slip stream of air from an air stripper at Operative Unit 29-31 at McClellan AFB was passed through a reactor that contained a lightweight, perforated, inert support coated with photoactive titanium dioxide. The reactor faced south and was tilted at a 45° angle from vertical so that the light-activated catalyst received most of the available sunlight. An online portable gas chromatograph with two identical columns simultaneously analyzed the volatile organic compounds contained in the reactor inlet and outlet air streams. Summa canister grab samples of the inlet and outlet were also collected and sent to a certified laboratory for U.S. Environmental IMPLICATIONS Current destructive technologies, such as biofiltration and incineration, for treating air contaminated with chlorinated ethylenes are less than ideal. Sensitivity to upsets and toxicity to microorganisms make biofiltration difficult to apply. Incineration requires considerable energy input to fully oxidize these recalcitrant compounds. This paper describes an ambient temperature process that can destroy trichloroethylene from the off-gas of an air stripper. The system uses the ultraviolet portion of the solar spectrum to activate a photocatalyst and destroy contaminants. The solar-driven process may provide a costeffective treatment system for remote applications and for applications where public perception takes precedence over the speed of cleanup. Alternatively, a lamp-driven process can be used for continuous operation.Protection Agency Method TO-14 analysis and verification of our field analyses.Three weeks of testing demonstrated that the treatment system's destruction and removal efficiencies (DREs) are greater than 95% at 10 SCFM with UV intensities at or greater than 1.5 milliwatts/square centimeter (mW/cm 2 ). DREs greater than 95% at 20 SCFM were obtained under conditions where UV irradiation measured at or greater than 2 mW/cm 2 . In Sacramento, this provided 6 hours of operation per clear or nearly clear day in April. A solar tracking system could extend operating time. The air stream also contained trace amounts of benzene. We observed no loss of system performance during testing.

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Alternatives for controlling organics in groundwater supplies

Cited by 32 publications

References 3 publications

Trichloroethylene and dichloroethylene: A critical review of teratogenicity

Trichloroethylene and dichloroethylene: A critical review of teratogenicity

Reductive dechlorination of chlorinated ethene DNAPLs by a culture enriched from contaminated groundwater

Pilot-Scale Demonstration of an Innovative Treatment for Vapor Emissions

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