MUNICIPAL SOLID WASTE LANDFILL SETTLEMENT MODEL CONSIDERING MICROBIAL KINETICS IN BIODEGRADATION

抄録

 A new landfill settlement model is proposed by coupling microbiological kinetics to simulate and predict municipal solid waste (MSW) landfill settlement. The model can be used to evaluate the effect of bacterial metabolisms on MSW landfill processes including settlement. The model is based on three mechanisms, namely, biodegradation of organic carbon mass, stress variation and moisture removal from waste particles (IMR) and pore spaces. Model simulation indicates that the contribution from biodegradation is small within a short period of simulation time. The landfill settlement has been dominated with water removal induced settlement where landfilling solid waste has high percentage of biodegradables and moisture content. To examine and simulate MSW landfill settlement process, a lab scale column experiment was carried out with synthetic MSW. The observed MSW landfill settlement in column experiment was used to verify the proposed model. The simulation and experiments suggested that effect of water removal will influence primary stage of settlement and this process will be introduced as a new mechanism for landfill settlement modelling. However, a careful demarcation between mechanically induced settlement and effect of internal moisture present in waste particles has to be explained by considering absorptive properties of waste particles, level of compaction and age of the waste.