In recent years, the necessity of recycling has been widely recognized. However, a social system for recycling has not been provided completely, as of yet and there is some fear that environmental impacts will increase as a result of recycling. From now on, in order to reduce environmental impacts with recycling in order to promote recycling, we have to scientifically and objectively show that we can reduce the environmental impacts with recycling. We must also make clear what will to reduce environmental impacts with recycling if we can not reduce the environmental impacts with present recycling system. In this paper, we examined the analytic method for the calculate the environmental impacts of the recycling phase using LCA method. With this method as we proposed, we showed that recycling influences a decrease in environmental impacts, and we reveal the specific process in the recycling system that increases environmental impacts.

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In order to estimate and control waste generation, its processes must be investigated at their origins. In the case of municipal wastes, the major generating sector is the whole of households, which generate solid wastes through consumption of household goods.
In this research, the consumption of household goods was analysed based on related reported statistical data. Among many households characteristics, “yearly income”, “number of household members”and“age of household head”were found to affect consumption significantly.
As the function of these three characteristics, equations for estimating consumption were formulated for each category of household goods. And these equations could estimate consumption reasonably, although there are some uncertainties associated with the statistical data.

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Five Refuse Derived Fuel (RDF) production facilities were studied in terms of energy balance, cost balance, and environmental impact. Mass balance of refuse components (cellulose, plastics, incombustibles, and water) were also estimated.
Three facilities were found to be energy efficient, i. e. a larger amount of energy is produced in the form of RDF than the amount consumed for processing and production. Low energy efficiency could be improved in the other two facilities if drying efficiency or operation rate were improved respectively. Heavy metal contents in RDF, one of the major environmental impacts associated with RDF production, were lower than those in household combustible waste due to source separation at households, as well as incombustibles separation in the facilities. The RDF production cost is, however, almost ten-fold that of the distribution price to the user.

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It is said that 70-90% of the mercury in municipal refuse incinerator flue gas is mercury chloride (HgCl₂) and the rest is metal mercury (Hg⁰), HgCl₂is generally easy to remove compared with Hg⁰. It is possible to remove HgCl₂with high efficiency using fabric filters, with the gas temperature at less than 150°C.
The purpose of this work, therefore, is to develop a dry mercury treatment system which achieves a high mercury removal efficiency of up to 80% for metal mercury at 200°C. The laboratory experiments were performed on fly ashes collected from electrostatic precipitators in municipal refuse incineration plants.
The following points have become clear from the experiments. Metal mercury can be removed with high efficiency at 200°C using fly ash from the municipal refuse incinerator. Both adsorbent substances such as unburnt carbon and CaCl₂contained in fly ash participates in the metal mercury removal mechanism. Adsobent substances and CaCl₂had a low removal efficiency when taken separately, but when they were present together, they had a high removal ability.

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A recycling technology has been developed for the molding resin residues, which are generated from printed wiring boards (PWBs) production process and consist of cured epoxy resin, glassfiber, and copper circuits. The residues of PWBs were pulverized by crushing and grinding, and the resulting powders were separated into a copper-rich powder and a powder consisting of glassfiber and resin (glassfiber-resin powder) by gravimetric and electrostatic method. More than 90% (maximum 96%) of copper was recoverable as the copper-rich powder from the residue powder of PWBs. This had an average particle size of 100-300μm. The recovered glassfiber-resin powder was found to be useful as a filler to improve the strength properties and the thermal expansion property of epoxy resin products, such as paints and additives.

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