The walkover survey can only detect the perforating damage prior to the tipping of waste. However, this may not be sufficient to ensure the long term integrity of the geomembrane. Especially at the early stages of landfilling the tipping of waste can adversely affect geomembrane integrity. Also, some hidden defects (e.g. on extrusion welds) can pass all tests and fail at a later date. The permanently installed geco system will detect this damage at the stage when the geomembrane is perforated.
The system consists of an array of sensing electrodes placed under the membrane and connected via cables to a monitoring terminal located at the perimeter of the survey area. Several modifications of a data acquisition system are available (manual, semi-automatic, fully automatic)
BHF Environmental has specialised in electrical leak detection surveys since 1994.
To detect and locate leaks in plastic membranes, the company uses the geco system. This application of geoelectrics is widely used as an effective tool in the process of Construction Quality Assurance in many countries, mostly for landfill applications, water reservoirs, and other lined liquid containments.
With our geco system the locating of any perforating damage to the geomembrane is rapid, accurate and cost effective. The system utilises the insulating properties of geomembranes. An electric current is applied across the protective layer placed over the membrane. Subsequently, the electric potential is mapped over the inspected area. Anomalies in electric field indicate the geomembrane damage.