Wastewater leakage identification in WWTP and concrete pipelines using integrated geophysical imaging methods

Abstract

Industry and mining activities covers a broad spectrum of processes that dispose an abundant amount of wastewater. Given the vast array of industries, there are equally large number of heavy metals, organic solvents, and hydrocarbons pollutants associated with its wastewater, posing a great threat to aquifers, especially groundwater. Main contributor of this polluting scheme are from the leakage of underground/surface storage tanks, effluent pipework, industrial sewers, and waste injection system. To ascertain the presence of pollution in the subsoil and groundwater resources, an integrated geophysical method can be the alternative of non-invasive methods. The presence of contaminants in subsoil alters the physical properties of rock formations and decrease pore-water resistance, therefore it can be mapped by geoelectrical resistivity. In this paper, study case was conducted in Medan Industrial Estate, Indonesia, to identify potential leakage under the Wastewater Treatment Plant (WWTP) and its pipework, using Geoelectrical Wenner and Magnetotelluric Method with 5 lines in the interval of 40-60 meters and Magnetotelluric Method throughout the 175 meters of pipework in the production area. Based on the Geoelectrical Method, an anomaly with a low resistivity value was detected within 7 meters of the ground depth. Meanwhile, in the Magnetotelluric Method, a moderate permittivity value was detected that is local and located within 2 meters depth which is where the pipe and the bottom of the WWTP storage tank is located. In conclusion, based on the results obtained from the Geoelectrical and Magnetotelluric Methods that have been carried out in the WWTP area and along the wastewater pipeline leading to the WWTP, no anomalies were found that lead to waste water leakage.