In situ ground water remediation using the trench and gate system

The trench and gate remediation system is a funnel and gate design modified for installation in tills and other low permeability sediments. Modificati ons include the addition of high hydraulic conductivity trenches along the upgradient side of the funnel walls and a discharge reinfiltration gallery downgradient from the treatment gate. Preferential ground water flow throug h the high permeability; trenches and reinfiltration gallery prevents mound ing, which otherwise forces flow beneath and around funnel walls. The resul tant capture zone is larger both horizontally and vertically, than the cros s-sectional funnel area and is significantly larger than the capture zone o f a similar funnel and gate system. The system constitutes an economical, i n situ, long-term contaminant plume capture and treatment method. In effect iveness and cost, the trench and gate system compares favorably with, or ou tperforms. other remediation systems in near-surface, ion permeability diss olved contaminant scenarios. A prototype trench and gate system was install ed at the East Garrington Gas Plant, Alberta, Canada, in 1995, The installa tion demonstrated the effectiveness of the concept, and the system has succ essfully prevented off-site migration of dissolved hydrocarbon contaminants .