Laboratory study on the hydraulic characteristics of mechanically and biologically treated waste in China

Mechanical biological treatment (MBT) can greatly reduce the amount of municipal solid waste (MSW) and has become a hot topic in environmental geotechnical engineering. To study the effects of factors such as the pressure, dry density, compression time under pressure, strain, and hydraulic gradient, permeability tests with saturated MBT waste were conducted by using a compression and permeability combined apparatus in an environmental geotechnical laboratory. The results showed that Darcy's law was applicable to the saturated MBT waste. The permeability coefficient was found to be inversely related to the pressure, dry density, compression time under pressure and strain. The logarithmic permeability coefficient and the variables (e.g., pressure) could largely be fitted to a linear function. Additionally, a prediction model for the permeability coefficient was established, and the permeability coefficient at different depths of MBT landfills was predicted. The results were then compared to previous studies on MSW and MBT waste to investigate the permeability mechanism.