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Operation and Performance of Horizontal Wells for Leachate Control in a Waste Landfill |
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| Authors: | R. P. Beaven S. E. Cox W. Powrie |
| Affiliation: | 1Senior Research Fellow, Univ. of Southampton and Richard Beaven Associates Ltd., 17 Station Rd., Tollesbury, Essex, CM9 8RB, U.K. (corresponding author). E-mail: richard.beaven@virgin.net 2Project Engineer, WJ Groundwater Ltd, 9 Park Rd., Bushey, Herts, WD23 3EE, U.K. E-mail: stevecox657@msn.com 3Head of School and Professor of Geotechnical Engineering, School of Civil Engineering and the Environment, Univ. of Southampton, Highfield, Southampton, SO17 1BJ, U.K. E-mail: wp@soton.ac.uk |
| Abstract: | This paper presents data on gas and leachate flow rates and leachate levels obtained during a 600?day pumping trial on three retrofitted horizontal wells in a domestic waste landfill at Rainham, United Kingdom. The changes in gas and leachate flow rate with time and atmospheric pressure, and the interaction between the two flows, are discussed. The spatial variability of the response of the leachate levels within the landfill is explored with reference to the anisotropy and heterogeneity of the permeability of the waste. It is shown that horizontal wells can be an effective means of controlling leachate heads near the base of a landfill, and that leachate levels must be measured using piezometers with a discrete response zone rather than fully screened observation wells if meaningful results are to be obtained. It is argued that the large amounts of gas pumped from the nominally saturated zone of the landfill must have come from the ongoing degradation of the waste within the zone of influence of the well. |
| Keywords: | Anisotropy Drainage Gas flow Landfills Pumping tests Two phase flow Wells |