Electrical detection of leaks in lined waste disposal ponds

Abstract

A method for detecting and locating leaks in the plastic liner of a waste disposal pond has been implemented and tested at a site near Budmerice in Slovakia. The method is based on detecting electric current flowing through holes in the insulating lining membrane. Unlike similar methods employed elsewhere, this implementation allows monitoring for leaks that may develop during and after filling the pond with electrically inhomogeneous solid waste. To accomplish this goal, sensing electrodes were placed below the membrane during construction. In operation, current was passed between an electrode inside the pond and another outside; the voltage caused by this current was observed on the buried sensing electrodes. The data were then processed to detect and locate any leaks in the membrane. An important practical concern is achieving acceptable detectability and location accuracy while using a sufficiently sparse grid of sensing electrodes. This problem was overcome by two processing steps: (1) calculating electrical potentials from the observed voltages and (2) performing a nonlinear inversion on subsets of the data. With this technique, observations made with a 10- × 8-m grid of electrodes, a relatively low‐power current source, and a simple receiver can provide accurate location information, even for small leaks. In a blind test, the system accurately predicted the locations of six leaks that were subsequently verified visually. Five of the leaks were cuts in the plastic typically measuring less than 2 × 0.1 cm, whereas the sixth leak was a group of many small holes. For the five, the typical location accuracy was about 30 cm, comparable to the basic survey location accuracy of the sensing electrodes.

Applications of Some New Techniques to Detect Groundwater Contamination at Mine Tailings Dams

“…We have applied these methods to mapping groundwater contamination near waste disposal sites (Buselli et al, 1990), determining soil salinity profiles (Buselli and Williamson, 1996) and locating sources of groundwater causing acid drainage at a mine tailings dam (Buselli and Hwang, 1996;Buselli et al, 1998). Similar examples are given by other workers, e.g., see Reid et al (1990), Frangos (1997), Campbell et al (1998), and Park (1998).…”

Time-dependent magnetometric resistivity anomalies of groundwater contamination: Synthetic results from computational hydro-geophysical modeling

“…Various geo-electrical techniques have proven the most suitable for mapping and monitoring contaminant transport in groundwater systems (Fitterman and Stewart, 1986;Buselli et al, 1988;Frangos, 1997;Greenhouse and Monier-Williams, 1985;Greenhouse and Slaine, 1986;Méndez-Delgado et al, 1999;Moore and Barker, 2001;Meads et al, 2003;Elders and Asten, 2004) since the contamination causes an increase in dissolved salts in the groundwater and hence the consequent increase in its electrical conductivity.…”

Optimized Enhanced Bioremediation Through 4D Geophysical Monitoring and Autonomous Data Collection, Processing and Analysis

“…This is shown by numerous publications on timelapse electrical geophysical monitoring applied to both hydrological and geochemical investigations, including (Daily 1984;Laine 1987;Parra 1988;Parra and Owen 1988;Bevc and Morrison 1991;Daily and Owen 1991;Van, Park et al 1991;Daily, Ramirez et al 1992;Shima 1992;White 1994;Ramirez, Daily et al 1995;Zhang, Mackie et al 1995;Ramirez, Daily et al 1996;Frangos 1997;Rodriguez and Rodriguez 1999;Slater and Sandberg 2000;Suzuki and Higashi 2001).…”