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Because of limited space, the siting and construction of a new SWM facility is a big challenge in Japan. An SWM facility should be socially accepted as well as environmentally and economically sound. This study aimed to investigate people's concerns about SWM facilities and their attitudes towards such facilities. A questionnaire was designed based on literature reviews and was sent to residents in three municipalities with different backgrounds. The questions covered concerns on the impact of an SWM facility, management aspects, unfairness of facility siting, and attitudes to facility construction.Of the many concerns, "pollution and health effect" had the highest rating, followed by "reliability", "damage to nature" and "cost". The rating was different between municipalities, reflecting their geographic and social backgrounds. Using factor analysis, correlations among concerns were analyzed, and five principal components were extracted, namely "pollution", "nuisance", "facility management", "planning of facility", and "merit/demerit". Although obvious correlations were not found between individual items of concern and attitudes to construction of a facility, the discriminant analysis indicated dominant concerns of attitudes, but the disagreement between actual impact and citizens were found. As for attributes, the "opposed" attitude decreased for residents who had visited an SWM facility, even if they had only seen it from outside.

The pyrolysis residue (SP) of sewage sludge (SS) produced at 500 °C was subjected to batch and column leaching tests to investigate the release of its organic and inorganic constituents and metals. For comparison, incineration ash (SI) obtained from a SS incinerator was also tested. Pyrolysis and incineration reduced organic matter of SS from 0.78 kg kg -1 -dry SS to 0.16 and 0.01 kg kg -1 -dry SS, respectively. Heavy metals remained in SP without being volatilized, although Cd and Pb were transferred into the off-gas during incineration.In the batch leaching test with the leaching liquid-to-solid mass ratio (L/S) = 10, the pH of the SS, SP, and SI filtrates was 6.3, 7.9, and 11.0, respectively. The total organic carbon concentrations were in the order SS (877l mg l -1 ) >> SP (99 mg l -1 ) > SI (26 mg l -1 ). The SP and SI filtrates met the landfill standard for the Cd and Pb concentrations (< 0.3 mg l -1 ). In the column tests, although the SP contained more organic matter than that of SI, its carbon discharge into the leachate under aerobic conditions was similar to that of SI under anaerobic conditions. The leaching of heavy metals, such as Cd, Cr, Pb, and Zn, was also suppressed in SP during the active decomposition of organic matter.We demonstrated that pyrolysis reduces the potential release of pollutants from sewage sludge in landfill, making it a promising method of treating sewage sludge before landfilling.

In this study, metal behavior in ash-melting and MSW gasification-melting facilities were investigated. Eight ash-melting and three MSW gasification-melting facilities with a variety of melting processes and feedstocks were selected. From each facility, melting furnace fly ash (MFA) and molten slag were sampled, and feedstock of the ash-melting processes was also taken. For the ash melting process, the generation rate of MFA was well correlated with the ratio of incineration fly ash (IFA) in feedstock, and this was because MFA was formed mostly by mass transfer from IFA and a limited amount from bottom ash (BA). Distribution ratios of metal elements to MFA were generally determined by volatility of the metal element, but chlorine content in feedstock had a significant effect on Cu and a marginal effect on Pb.Distribution ratio of Zn to MFA was influenced by the oxidizing atmosphere in the furnace.High MFA generation and distribution ratio of non-volatile metals to MFA in gasification-melting facilities was probably caused by carry-over of fine particles to the air pollution control system due to large gas volume. Finally, dilution effect was shown to have a significant effect on metal concentration in MFA.

Solid residues from municipal solid waste incineration (MSWI) can be categorized as air pollution control residues (AR) and bottom ash (BA). Both categories pose a particular environmental threat on account of the risk of the release of dioxins and metals. In Japan, handling of MSWI residues is of major concern and the treatment of AR prior to land®lling is stipulated. Accepted treatment techniques are melting, cementitious S/S (stabilization and solidi®cation), stabilization with a chemical agent and acid extraction. These methods are reviewed and evaluated in this paper with respect to: quality; quantity and utilization of end products; treatment costs; energy demand and process reliability. Thermal processes are superior regarding dioxin removal as well as material recovery and reuse, but treatment costs can be as high as 60 000 ¥ t -1 , i.e. one order of magnitude higher than for other processes. Cementitious S/S and chemical stabilization are characterized by the ease of operation, but the solid waste mass is increased by up to 40 and 10 wt.-%, respectively. Acid extraction is a proven and reliable technique and is inexpensive: nevertheless, it has the smallest share of the market.

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