Temperature in a municipal solid waste landfill layer can rise up to 60°C and above, because of biodegradation and other processes. This has significant effects on biological, chemical and physical phenomena in the layer, which has been elucidated by various fields and theoretical studies. Effective thermal conductivity (k_e) is an essential property in order to estimate and control temperature distribution of landfill layers.
A laboratory-scale experimental apparatus was set up for measuring ke of a solid waste packed bed. Values of ke of 2 kinds of ashes, crushed incombustible refuse and artificial refuse were measured.
Consequently, values of ke were in the range of 0.04 to 1.1 J/ (m⋅s⋅°C), and varied with the type of refuse, apparent density and water content of the packed beds. Furthermore, a predicting method for ke was proposed. It was estimated as geometric means of 2 predicted values by series and parallel models which are simple and typical models for calculation of ke of porous materials. The predicted values of ke agreed with the observed values within ± 50% errors.

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The importance of gas mixing in combustion chamber was demonstrated by the renovation of an existing municipal solid waste incinerator. The modification of the furnace configuration and the improvement in the supply of the secondary air allowed the reduction of carbon monoxide concentration and dioxin levels to a great extent. In addition, the automatic combustion control system and the reduction of ESP temperature by the gas cooling system provided for further reduction in dioxin emission levels, by approximately 1/10 compared with before renovation.

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