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Electrical Leak Detection System for Landfill Liners: A Case History |
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| Authors: | CC White RD Barker |
| Institution: | Christopher C. White;is a senior hydrogeologist with environmental management consultants Aspinwall &Co. Ltd. in the United Kingdom (Walford Manor, Baschurch, Shrewsbury, Shropshire, SY4 2HH;e-mail: Chris.White@Aspinwall.co.UK). He received his B.Sc. (1978) in geology and his M.Sc. (1981) in hydrogeology from the University of Birmingham. He has 17 years experience in hydrogeological and geophysical investigations. His interests are in ground water monitoring and ground water remediation at chemical facilities;he is a member of the ASTM D18.21 Committee. White has undertaken projects in the United Kingdom, Africa, Middle East, and Far East. Ron D. Barker;is a senior lecturer at the University of Birmingham (School of Earth Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.;e-mail: R.D. Barker@bham.ac.uk). He received his B.Sc. (1967) in geology at the University of Nottingham and his M.Sc. (1969) and Ph.D. (1971) in applied geophysics at the University of Birmingham, England. He was a lecturer in ground water geophysics at the Federal University of Bahia, Brazil, until 1975 when he returned to the University of Birmingham as a research geophysicist. From 1978 to 1983 he was director of Alta Geophysics and worked on ground water projects in Indonesia, Zimbabwe, and Europe. He is currently director of the M.Sc. course in applied geophysics at the University of Birmingham and leads a small research group in environmental geophysics. He is a chartered geologist, a member of SEG, EAEG, and EEGS (Europe), and is a director of Campus Geophysical Instruments Ltd. |
| Abstract: | As landfill specifications become more stringent in the United Kingdom, the development of increasingly sophisticated monitoring methods is necessary to meet environmental protection goals. This case history describes the development of a 2-million-cubic-meter-capacity landfill located in a sandstone quarry and 1 km from a public water supply borehole, where the sensitivity of the site to ground water contamination and the proximity to a public water supply borehole are particular issues. The landfill design incorporated a more sensitive environmental monitoring system, using a geophysical technique. The monitoring system comprises a permanent grid of electrodes installed beneath the landfill, connected by multicore cable to a computer-controlled earth resistance meter and switching unit in the site weighbridge. It was designed to detect holes in the landfill liner prior to and after covering with waste and to monitor the migration of contaminants beneath the landfill before they reach the perimeter observation boreholes, should leakage occur. Such monitoring can enable the integrity of the landfill to be routinely reviewed; holes can be repaired if they are readily accessible and, if not, monitoring provides an early warning to enable the implementation of any additional monitoring or corrective action, based on the environmental risk posed by the site. The system was first used as a quality assurance test once the landfill liner, which covered an area of 3 hectares, was installed. The system proved sensitive, detecting a hole consisting of two narrow knife cuts. Such sensitivity allows a high degree of confidence to be placed upon the integrity of the liner resulting in a significant contribution to public reassurance. The landfill is now operational, and monitoring using the geophysical system will be undertaken on a monthly basis for the first year, with the frequency of monitoring reviewed thereafter. |
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