Laboratory determination of water retention characteristics and pore size distribution in simulated MSW landfill under settlement

To examine how water retention characteristics in a landfill environment change as a result of solid waste settlement and to derive the evolution of pore size distribution, a lab scale long column experiment was carried out at two different time periods while keeping all the other characteristics constant. Two columns, Column 1 and Column 2, were used in the study. The log normal distribution model was applied to model the experiment data. The Column 1 was used to obtain the water retention curve at time 0 day and the Column 2 at time 180 day. During the experiment period, landfill settlement was mainly in the primary stage of settlement. Pore size distribution was obtained by assuming that the capillary theory is applicable in the landfill environment. The results showed that water retention characteristics in solid waste landfill environment is varied with time and influenced by landfill settlement due to the changes in pore spaces. The obtained results will be taken into consideration when simulating unsaturated leachate and gas flow in municipal solid waste landfill environment.