Evolution of physical and mechanical properties of municipal solid waste in a landfill with low kitchen waste content

The classified treatment of the municipal solid waste (MSW) will lead to a significant decline in the proportion of kitchen waste in landfills in China, which puts forward new requirements for the long-term safe operation of landfills. To evaluate the evolution of the physical and mechanical properties of waste in low kitchen waste landfills, the in-situ pumping and resistivity tests, and the laboratory tests on waste components, water content and shear strength of an MSW landfill with low kitchen waste content in China are carried out. The major conclusions are as follows: (1) The waste components only slightly change after two years of pumping, but the properties of the MSW become more scattering. (2) The water content is at a high level of 86%~161% which is affected by the landfilling history and location, and the range decreases to 42%~116% after pumping. The overall leachate level declines, but there is a local area with a high water content at the depth of 10~15 m, and the local leachate accumulation may be due to component dislocation and migration caused by pumping. (3) The cohesion and internal friction angle vary widely, and their ranges are 0~20 kPa and 15°~30°, respectively. The cohesion is overall lower than that of the domestic traditional landfill with a high kitchen waste content. The shear strength of the MSW after pumping is generally reduced, but the shear hardening phenomenon is more obvious.