Abstract: The sewage sludge-municipal solid waste (MSW) mixed landfill is one of the ways of sewage sludge disposal. The dry density parameter of the sewage sludge and MSW mixture have important influence on the strength and stability in landfill. The compaction tests on the mixture are conducted under different compaction energies and sewage sludge contents conditions to study the compaction characteristics. The results show that compared to MSW, the dry density of the mixture is increased by 2.74%-32.50%, improving the compaction characteristics of MSW. The dry density increases with the increase of compaction energy; and a hyperbolic model can be used to express this relationship. The physical meanings of model parameters are also analyzed. The variation laws of model parameters are discussed. It is found that varies from 0.373 to 0.750, and that varies from 1.958 to 2.158. The dry density increases with the increase of sewage sludge contents; and this relationship can be described by a logarithmic model. The variation laws of model parameters are also discussed. It is also found that b varies from 0.331 to 0.776, and that c varies from 0.052 to 0.164. Comprehensively utilizing these two models, the dry density parameter of the mixture can be predicted; the workload of testing can be reduced; and the theoretical basis can be provided for the design and analysis of the landfill site. The compaction evaluation method and the compaction mechanism of the mixture are analyzed. According to the variation trend of the dry density, the mixture is judged whether densification.

Key words: sewage sludge, municipal solid waste(MSW), landfill, dry density, hyperbolic model, logarithmic model