Patent ID: 8651768

Claim:
A method for directing a non-aqueous phase liquid (NAPL) from a NAPL-contaminated sediment beneath a surface of a body of water towards a NAPL accumulation zone comprising the step of: interposing in a path of a plurality of NAPL-entraining gas bubbles migrating between the sediment and the surface a device through which neither the gas nor the NAPL can percolate, the device comprising a first layer of a material through which neither the gas nor the NAPL can percolate and a transmission layer interposed between the first layer and the NAPL-contaminated sediment, the transmission layer defining the accumulation zone and a vent in fluid communication with the accumulation zone, at least one of the transmission layer and the accumulation zone comprising an amendment, the device sloping upward towards the surface to an extent sufficient to direct the gas bubbles from under the device to the vent and into the accumulation zone.