LOCATING LANDFILL LEAKS COVERED WITH WASTE

SUMMARY : A newly constructed single-lined geomembrane municipal solid waste (MSW) landfill cell developed leaks after two to five meters of waste were placed in the cell. The primary liner was initially leak tested using an electrical leak location method after the protective drainage soil was placed on the liner. All leaks that were located were repaired. Therefore, the reported leakage was caused by damage to the liner during the placement of the waste material. Because the landfill had up to five meters of waste material covering the liner, a standard electrical leak location survey was not practical. Therefore the newly-developed Electrical Leak Imaging Method (ELIM) was used to locate leaks. Three leaks were located using ELIM. The leaks were repaired and no further leakage has been reported. 1. INTRODUCTION Locating leaks in geomembranes after installation is an essential element to insure that the lined facility is functioning as designed. Typical field test methods for locating leaks in liners include: vacuum box, air pressure, spark test, dye, and electrical leak location. The only method that is capable of accurately locating leaks in the geomembrane after a protective soil cover is placed over the liner is the electrical location method. An advancement of the electrical leak location method is the Electrical Leak Imaging Method (ELIM). This method can be used as a permanent monitoring system or as a mobile system to solve leak problems in operational landfills. The ELIM method detects electrical paths through the geomembrane liner caused by water or moisture in holes through the geomembrane liner. A voltage is connected to one electrode placed in the soil covering the liner and to a second electrode placed in the leak detection zone for double-lined systems or in earth ground for single-lined systems. Electrical current flowing through the leaks in the liner produces localized anomalous areas of high current density at the leaks. These areas are located by making potential measurements around the perimeter of the landfill or with widely spaced grid of electrodes on the floor area of the landfill cell. The data is then processed using specialized imaging software to locate leaks in the geomembrane liner.