Development of zero-valent iron as an in situ reactant for remediation of VOC-contaminated ground water

Conference · · Ground Water; (United States)

OSTI ID:7124458

Gillham, R W; O'Hannesin, S ^[1]

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1. Univ. of Waterloo, Ontario (Canada)

This paper gives an overview of recent studies concerning the use of zero-valent iron as a reactant in a permeable in situ wall for removal of chlorinated organic contaminants. Gillham and O'Hannesin (1994) reported the results of laboratory batch tests in which aqueous solutions of chlorinated methanes, ethanes, and ethenes were added to 10g of 100-mesh iron filings in 40 mL hypovials. Concentrations were observed to decline exponentially over time, suggesting a pseudo first order degradation process. Of the 14 compounds tested, with the exception of dichloromethane, all showed measurable rates of degradation, with the rate increasing with an increase in the ratio of surface area of iron to solution volume. Normalizing the results to a surface area to volume ratio of 1 m[sup 2]/mL gave half-lives ranging from 0.013 to 19.7 hr for hexachloroethane and cis 1,2-dichloroethene respectively. Recognizing the potential application, a field demonstration was conducted at Canadian Forces Base Borden. A reactive wall, 1.6 m thick containing 22 percent iron and 78 percent sand by weight was constricted downgradient of a continuous source of dissolved perchloroethylene (PCE) and trichloroethylene (TCE). Concentrations reaching the wall were approximately 253 and 43 mg/L for TCE and PCE respectively. Approximately 90 percent of the mass of TCE and 86 percent of the mass of PCE was removed within the wall, and the increase in the chloride concentration confirmed that the process of removal was indeed dechlorination.

• OSTI ID: 7124458
• Report Number(s): CONF-9410209--
• Conference Information: Journal Name: Ground Water; (United States) Journal Volume: 32:5
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540250* -- Environment
Terrestrial-- Site Resource & Use Studies-- (1990-)
CANADA
CHEMICAL REACTIONS
CHLORINATED ALIPHATIC HYDROCARBONS
DECHLORINATION
DEHALOGENATION
DEVELOPED COUNTRIES
ELEMENTS
GROUND WATER
HALOGENATED ALIPHATIC HYDROCARBONS
HYDROGEN COMPOUNDS
IN-SITU PROCESSING
IRON
METALS
MILITARY FACILITIES
NORTH AMERICA
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
OXYGEN COMPOUNDS
PROCESSING
REMEDIAL ACTION
REMOVAL
TECHNOLOGY ASSESSMENT
TRANSITION ELEMENTS
WATER
WATER RECLAMATION