The two-layered sealing system offers the flexibility to be monitored either continuously or periodically.
To enable the location of damage or faults within the liner system, the monitoring zone is typically divided into individual control fields. Each control field has two monitoring modes (one for vacuum checks and a wire for electrical monitoring). The division of the monitoring zones into individual control fields can also help limit the spread of contaminants in the entire monitoring zone by allowing quick and precise damage location.
After completion of the project, the entire monitoring zone is put under a negative pressure of 0.3 to 0.6 bar. The vacuum pump is located in a measuring cabinet that also contains the leakage indicator. A sudden drop in the negative pressure indicates a faulty control field in the system. Repair measures can then be initiated selectively and quickly.
Another monitoring tool is based on electro-resistivity measuring principles, where a unique conductive geotextile is installed in the monitoring zone between two geomembranes. The geotextile, along with a measuring and evaluating matrix-like structure are connected with the local data unit, which collects the resistance distribution within the special nonwoven geotextile.
If the conductive geotextile becomes hydrated due to damage in the overlying geomembrane, the electrical resistance of the geotextile in this area changes. This change in resistance releases an alarm, so that corrective actions can be performed in the specific area of the damage.