Electrical tomography survey of a landfill site

There are an estimated 230 landfills in Malaysia, some of which are located near communities and water sourees. Besides contamination of ground water due to chemical leachates, gas migration can also be a serious problem. Landfill gases are formed during the decomposition of organic wastes and consists of a mixture of methane (C~), carbon dioxide (C02), nitrogen (N2) and volatile organics. The use of 2D electrical tomography surveys (Griffiths and Barker 1993) to map various features in landfill sites was investigated in this research. Tests with synthetic data for different landfill models were first conducted. Surveys were also carried out to delineate the various fill materials, map leachate movement and gas accumulations. The results from two of the survey lines with possible gas traps are given in this paper.