In the United States, volatile organic compounds (VOCs) are commonly monitored at landfill sites because they are indicators of impacts on groundwater . Groundwater impacts at landfills can result from waste in contact with water (leachate), infiltration of water through waste into groundwater (leachate); or landfill gas migration followed by contact with groundwater. Because both leachate and landfill gas contain VOCs, either can cause groundwater impacts by VOCs.
Differentiation between landfill gas and leachate as the source of groundwater impacts can be important because treatment of leachate (aqueous) sources typically uses costly pump-and-treat methods whereas landfill gas impacts can often be remedied by modifying the gas control system or its operation, which is less costly. Methods have been developed to differentiate between VOCs from leachate and landfill gas sources. These methods include evaluation of groundwater radioisotopes, inorganic water quality parameters, specific volatile organic compounds, and comparison of aqueous and headspace VOC concentrations. Groundwater impacts from landfill gas can occur upgradient of monitoring wells or within the well. The effects of corrective can take several years to return groundwater quality to pre-impact status. Case studies will be used to illustrate these principles.
About the speaker
Henry Kerfoot is a Principal Landfill Gas Geochemist with URS Corporation Pty Ltd., Melbourne. He recently immigrated to Australia from the USA to work on landfill-gas and landfill associated issues. His background includes gas and groundwater evaluations at landfills, assessment of fate and transport of chemical constituents at contaminated industrial sites, innovative in situ remediation of groundwater, vapour intrusion, and geochemical forensics. Henry originated the concept that landfill gas, rather than leachate (waste pore water), could be the source of VOCs in groundwater samples at landfills and he developed the use of gas/groundwater concentration comparisons, radioisotopes, groundwater concentrations of semi-volatile organic compounds and inorganic parameters to identify landfill gas as the source of groundwater impacts. Henry was also a pioneer in soil-gas monitoring and he has modeled gas/water exchange of constituents to evaluate the in situ degradation rate of hydrocarbons.
Come join us
Date: 5 March 2013
Time: 5:30pm meet and greet for a 6pm start.
Location: URS (Level 6, 1 Southbank Boulevard, Melbourne)
No need to RSVP
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