10.2190/TMKG-4QU9-1FAL-PM3R TMKG4QU91FALPM3R 337 IMPACT OF THREE DIFFERENT HYDRAULIC CONDUCTIVITY EXPRESSIONS ON MODELING LEACHATE PRODUCTION IN LANDFILLS 337 345 20021002 20021002 20021002 20021002 TMKG4QU91FALPM3R.pdf http://baywood.metapress.com/link.asp?target=contribution&id=TMKG4QU91FALPM3R 4 O. OLAOSUN H. R. BAHERI University of Calgary, Alberta, Canada Unsaturated flow in porous media, modeled by Richard's Equation, requires the identification of the moisture advective velocity in terms of hydraulic conductivities. In this study, the impacts of three hydraulic conductivity expressions on the ability of the unsaturated flow model to predict leachate production in landfills were investigated. The two power expressions (Power I and II) and PITTLEACH-2 hydraulic conductivity expression were used along with the Richard's Equation to estimate the leachate flow in solid wastes. Experimental data on leachate generation from eight laboratory scale cells were also used to assess the impact of different expressions on prediction of leachate flow. It was found that using PITTLEACH-2 hydraulic conductivity expression resulted in much better predictions of the leachate generation in all the eight cases studied here. G. S. Campbell, A Simple Method for Determining Unsaturated Conductivity from Moisture Retention Data, Soil Science, 117:6, pp. 311-314, 1974. O. Olaosun, Modeling Leachate Production in Heterogeneous Municipal Solid Waste Landfills, MSc. thesis, University of Calgary, 2001. R. D. Jackson, Porosity and Soil-Water Diffusivity Relations, Soil Science Society of America Journal, 27, 1963. D. G. Fenn, K. J. Hanely, and T. V. DeGeare, Use of Water Balance Method for Predicting Leachate Generation from Solid Waste Disposal Sites, EPA/630/5W168, U.S. EPA, Cincinnati, Ohio, 1975. P. R. Schroeder, P. A. Dozier, P. A. Zappi, B. M. McEnroe, J. W. Sjostrom, and R. L. Peyton, The Hydrologic Evaluation of Landfill Performance (HELP) Model: Engineering Documentation for Version 3, U.S. EPA Risk Reduction Laboratory Cincinnati, Ohio 45268. P. Dass, G. R. Tamke, and C. M. Stoffel, Leachate Production at Sanitary Landfill Sites, Journal of Environmental Engineering Division, ASCE, 103:EF6, pp. 981-988, 1977. G. P. Korfiatis and A. C. Demetracopoulos, Moisture Transport in Solid Waste Columns, Journal of Environmental Engineering, 110:4, pp. 780-796, August 1984. A. B. Al-Yousfi, Modeling of Leachate and Gas Production and Composition at Sanitary Landfills, Ph.D. dissertation, University of Pittsburgh, 1992. P. R. Schroeder, N. M. Aziz, C. M. Lloyd, and P. A. Zappi, The Hydrologic Evaluation of Landfill Performance (HELP) Model: Engineering Documentation for Version 3, U.S. EPA Office of Research and Development, Washington, D.C., 1994. S. Ahmed, R. M. Khanbilvardi, J. Fillos, and P. Gleason, Two-Dimensional Leachate Estimation through Landfills, Journal of Hydraulic Engineering, 118:2, pp. 306-322, August 1992. C. Zeiss and M. Uguccioni, Modified Flow Parameters for Leachate Generation, Water Environmental Research, 69:3, pp. 276-285, 1997. R. J. Charbeneau, Kinetic Models for Soil Moisture and Solute Transport, Water Resources Research, 20:6, pp. 699-706, 1984.