LANDFILL GAS TRANSPORT IN KARST

摘要

Adjacent property owner concerns have typically excluded offsite investigations into the extent of landfill gas impacts. Direct-push gas monitoring techniques enable investigators to actively map and track landfill gas distribution and migration offsite via simple, low impact methods that respect adjacent property owner concerns. Characterizing the extent of offsite impact in karst allows the identification of previously unseen primary gas transport mechanisms and flow paths existing within voids in the bedrock. Several case studies at closed landfill sites situated in karst areas of the Valley and Ridge geologic province of Tennessee and Virginia are presented to illustrate the potential for offsite impacts resulting from the transport of landfill gas via the void network. At each site, offsite gas impacts have been remediated by accessing the bedrock voids and redirecting the flow to the surface with passive vents installed at the property line. Initially, the offsite gas monitoring completed at each case study site enabled investigators to track the gas migration to the bedrock voids. Ongoing offsite monitoring demonstrates the effectiveness of the bedrock void vents.