We believe that liner integrity surveys are a natural extension to our geomembrane liner CQA services, so we’ve invested heavily in staff training, certification and equipment.
The principle of the geoelectrical leak detection method on a soil or water covered geomembrane liner is to apply a voltage across the liner and locate points where electrical current flows through discontinuities (leaks) in the geomembrane. Voltage is applied to an electrode in the soil or water covering the geomembrane and to another electrode in a conductive material under the geomembrane liner. Because the geomembrane is an electrical insulating material, the applied voltage produces a uniform electrical potential distribution in the material above the liner when no leaks are present.
If a leak is present in the liner the electrical current will flow through the leak, which produces high current density and a localized abnormality of the potential distribution in the material above the liner. Electrical measurements are made in the soil or water covering the geomembrane using either a dipole survey probe or scissor action water survey probe. A compact monitoring meter produces an audio signal that increases in intensity when approaching a leak, and then becomes immediately silent when the leak is passed. Two arrows on the meter will then indicate whether the leak is in front or behind the probe, and their intensity indicates the direction of the leak. The leak is zeroed in on as it is approached, pinpointing it in real time.