For improving recyclability of home appliances, shorter time to disassemble them at scrapping is necessary. But hardly any method estimating recyclability has been developed, in comparison with general characteristics of manufacture, mechanical strength, energy consumption, etc.. In this report it is proposed that a new estimating method for disassemblable characteristics can appraise disassembly in relative terms, using a new time index.
First, we show that joints could be classified according to release time of each joint. This is the result of our disassembling a refrigerator used for 10 years. Next, the time index, called “disassemble index”, was defined according to this classification. Then we show that the sum of disassemble indexes totaled from joints was proportional to the sum of actual release time of joints, in the case of disassemble of 5 home appliances. Finally, we show that the disassemblable characteristic among different appliances could be estimated in relative terms, expressing total disassembly time with a disassemble index composed of search time, release time and disconnection time.

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A one year survey of Refuse Derived Fuel (RDF) properties has been done for four RDF facilities in which RDF is produced from household waste.
Fuel properties of RDF are mostly influenced by garbage and plastics content. High moisture content of garbage reduces the efficiency of incombustible separation, leading to high ash content of RDF. High plastics content of raw refuse increases the calorific value, and volatile chlorine content of RDF. The volatile chlorine for the most part comes from polyvinyl chloride (PVC), so HCl gas control is required for two facilities which use only plastics or plastics & paper components, but not for the other two facilities, whose input is almost the same components as household waste, including garbage. Moisture content of 10 percent or less may not cause putrefaction when RDF containing garbage is stored.

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As one of the new means of safe treatment of polyvinyl chloride wastes, reaction conditions of dechlorination in hot water at up to 400°C were investigated. Results may be summarized as follows.
1) Dechlorination can be done by a one hour reaction in hot water at sub-critical conditions over 300°C, and by a 20 hour reaction at 250°C, with presence of metal iron, or in alkaline solution.
2) With metal iron, the dechlorination reaction is dominant and decomposition reaction seems not to proceed, so that the residue is a dechlorinated solid.
3) In alkaline solution, dechlorination and hydration reactions proceed simultaneously so that the main reaction products are water-soluble or in-soluble liquids, and little solid residue remains.
4) With metal iron in alkaline solution, the dechlorination reaction is dominant, but at supercritical conditions decomposition reaction easily occurs.

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A mathematical model is presented to compute the behavior of fluid flow, heat-and masstransfer in a dried sewage sludge melting furnace using a coke-packed bed. A system of equations describing the conservation of mass, momentum and enthalpy is used to simulate the transport phenomena. Finite volume method is used to solve the system of coupled non-linear partial differential equations on the gas phase and coke particles. For the dried sludge particles, a set of ordinary differential equations is solved using Lagrange method for computing the particle trajectories. The numerical predictions are in reasonable agreement with the measurements obtained by a bench-scale melting furnace. The influence of process operating variables such as swirl velocity, as well as combustion characteristics of the dried sluge, on the coke consumption of melting furnace is studied using a field modeling technique. The principal conclusion reached from this study is that upgrading of this melting furnace can be achieved with modifications of size distribution and composition of the dried sludge, together with the optimization of process operating variables. This model is applied effectively as an engineering tool for designing the furnace and improving the performance of furnace in operation.

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