Locating geomembrane liner leaks under waste in a landfill

An Electrical Leak Imaging and Monitoring (ELIM{sup SM}) survey was used to locate leaks under 2.5 meters of stabilized waste in an active geomembrane-lined landfill. The landfill is lined with two 2-mm thick HDPE geomembranes that are separated by a geonet drainage layer. The primary liner is covered with 600 mm of drainage sand and 2.5 meters of stabilized waste for a total cover thickness of more than 3 meters. The principle of the ELIM method is to apply a voltage across the geomembrane liner and then to measure the resultant electrical potentials at widely spaced points. The data is processed using specialized mathematical inversion algorithms to image the locations of the leaks. The processed data indicated a leak near the center edge of the landfill cell. The suspect area was excavated to reveal two 80-mm long cuts in the primary liner.