This study examines the production of hydrogen, which is attracting much attention as a new source of energy, from biomass resources and various wastes by considering future material cycles in society. The technological aspects of thermal pyrolysis-gasification and reforming processes for generating hydrogen and useful C-1 compounds, as well as processes for purifying and separating synthesized gases, are investigated. Major and minor contaminants that could adversely affect the environment and cause problems for downstream systems such as fuel cells are also discussed. The paper surveys the latest gasification and reforming technologies and then identifies problems related to raising the efficiency of the processes by using catalysts.

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Ash samples were experimentally heated in order to investigate the formation potential of dioxins by using a quartz glass tube reactor. The samples were collected from gas cooling processes such as boilers and gas cooling towers in gasification melting systems. Emphasis was placed on finding a parameter that could be used to estimate the formation potential of dioxins, and on examining the influence factors. The effects of pretreating the ash sample were tested using thermal treatment at 500 or 600°C, Soxhlet extraction by dichloromethane, or rinsing by water. The results showed that the formation potential was decreased by the pretreatments, except for Soxhlet extraction. Hence, carbon content in ash and water-soluble constituents including metal chlorides were found to be important factors for the formation of dioxins. The total amount of dioxins per gram of ash, which was defined as the sum of dioxins emitted with flue gas during the gas sampling time, and dioxins contained in ash after heating generated from ashes of gasification melting systems were 1.3-330 ng/g. A linear relationship in logarithmic scale was found between carbon content and the total amount of dioxins. Metal compounds generally did not show water solubility based on the analysis of extracted water. However, suspected compounds containing lead were shown to be soluble, which might explain the change of formation potential by water rinsing.

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Fly ash generated from municipal solid waste incinerators is designated as specially controlled waste in Japan, and there is a legal obligation to make it harmless before disposal. Technologies for making wastes harmless require excellent reliability and environmental safety. Slag is generated as a byproduct of various types of melting furnaces, and technologies are required for effectively recycling it as a useful resource. This paper reports new technologies developed for treating incinerator fly ash and making them harmless by applying metal smelting technologies. The paper also presents a new technology for mixed, simultaneous treatment of fly ash and slag. In the newly developed fly ash treatment process, fly ash is formed into pellets, and baked in a rotary kiln to make it harmless. The baked product is recovered as a material that can be easily used effectively in various applications. In addition, secondary fly ash is treated to recover sub-materials for metal smelting. These technologies are characterized by the fact that the baked products are obtained as pellets that have excellent environmental safety and enhanced strength, and secondary fly ash is also effectively recycled as a smelting material. Experiments were performed on fly ash of various compositions using experimental equipment that had a treatment capacity of 100 kg/hour.

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It is of growing social concern that water quality and aquatic environment are threatened with pollution by leachate from waste-landfill sites. This study investigates medaka-embryo toxicity of treated leachates that are released into aquatic environments as effluent. Leachate exposure does not inhibit induction of hatching enzymes in medaka embryo. Leachate-exposed embryos showed delayed hatching compared to non-exposed embryos. Furthermore, exposure of larvae engendered malformations such as scoliosis and lordosis. Those malformations were observed mostly subsequent to exposure of leachate that was diluted to 60%, which implies a range of 250-300 mOsm/L. This osmotic pressure is similar to that of blood of teleost fish, including medaka fish. This osmotic pressure effect on enhancement of malformation toxicity was also observed in exposure of carbaryl (an insecticide) at a constant carbaryl concentration (4 mg/L) and different osmotic pressures (10-400 mOsm/L) . Malformation by carbaryl exposure was observed mostly at 250-300 mOsm/L. It decreased markedly at 400 mOsm/L. These results suggest that osmotic pressure is a factor in enhancing leachate toxicity. The release of the treated leachates into aquatic environments should be seen as a new environmental risk to aquatic organism/ecosystems.

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Manual labor by workers is often necessary in the recycling process. Until now, in studies of life cycle analysis, manual labor has hardly been calculated into the environmental load. Although some machines or equipment are used in the process, these evaluations can not be considered comprehensive as they ignore analysis of environmental load for the manual labor process. In this study, we investigated actual conditions in recycling facilities, and tried to analyze the environmental load incorporating manual labor that is considered indispensable within the recycling process. The results were applied to the process of motor dismantling, comparing environmental load by worker manual labor with that of an automatic dismantling system in which shape memory alloy screws were used. Through this case study, we examined the possibility of replacing manual labor with an automatic dismantling system in the recycling process.

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In order to recover a useful resource from the incinerator ash of sewage sludge, an examination of elution was conducted by soaking in sodium hydroxide solution. Using 4 samples of incinerator ash with different phosphorus contents, the elution property of phosphorus and useful elements was clarified. For phosphorus, the role of temperature and time in elution was verified. The concentration of the incinerator ash and its temperature were studied in order to determine effective elution conditions for aluminum and zinc. The elution content of aluminum was not related to aluminum concentration in the ash, but rose in relation to the phosphorus content in the ash. Because phosphorus and aluminum were the same characteristics of elution despite aluminum content ratio, it is assumed that aluminum phosphate is eluted in ash. This showed that the elution ratio of aluminum is related to temperature and ash concentration. The maximum elution rate of zinc was 16%, when elution was performed at 80°C using 10% Sodium Hydroxide solution.

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Obtaining land for new landfill sites in Japan is now exceedingly difficult. For this reason, various alternative cover materials that decrease the necessary volume of cover are being developed in order to prolong the effective life of existing landfill sites. It is necessary to know the impact of these cover materials on waste stabilization and the characteristics of leachate quantity and quality. In this research, a long-term experiment was conducted using three large two-dimensional lysimeters with no cover, soil cover, and an alternative cover (used paper) .
As a result of this experiment, it was found that a soil cover layer caused channeling in the water movement and soluble pollution was not uniformly washed out. It was also found that stabilization of the landfill waste was delayed because the supply of oxygen needed for decomposition of the organic pollution elements was insufficient. In the case of the alternative cover material, permeability and ventilation were better than that of the soil cover and the waste stabilization was accelerated.

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Bisphenol A (BPA) in leachate and treated water from municipal solid waste landfills and industrial waste landfills were analyzed. In the case of municipal solid waste disposal sites, the level of BPA was < 0.05-4, 960, μg/L in leachate, and < 0.05 19.8, μg/L in treated water, respectively. High concentration of BPA was detected from a co-disposal site of shredded incombustible/large waste and incinerator ash. On the other hand, the level of BPA was < 0.05 -494μg/L in leachate, and < 0.05-55.2μg/L in treated water from industrial waste disposal sites. According to the results of repeated leaching tests on waste samples, BPA was easily and continuously leached from products made of plasticized polyvinyl chloride (PVC) and the total amount of leached BPA was higher than from products made of polycarbonate. Therefore, when high concentrations were detected, it was estimated that, thought the concentration of BPA contained in leachate varies widely, it continues to leach at a high-level for some time.

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In Japan, some household electric appliance companies (HEAC) have made the changeover to Non-Halogen (Deca-Bromo-Diphenyl-Ether (DBDE) ) as a flame retardant agent in the plastic compounds for new types of Television Cabinets (TV-C) . Most recycled plastic compounds generated at HEAC recycling factories however, still contain used DBDE from the old type TV-Cs (manufactured before 2000) . It is, therefore, rather difficult for HEAC to use these compounds as recycled materials for use in the new type TV-C in Japan.
Due to this reason, because of restrictions on recycling use and from the point of view of cost, most of these recycled compounds containing DBDE are exported overseas, mainly to China, as black color compounds. According to traders in the recycling field, once DBDE contaminated compounds are exported overseas, it is possible that they are being mixed with virgin black color compounds and then being exported back to Japan again as a material for black resin used in video cassettes, etc. In light of this information, the chemical composition of the samples to be sold at a general-volume sales store in Japan were investigated.
As a result of this investigation, both bromine and antimony were detected in the major HEAC-labeled video cassettes made in China; bromine was also detected in other general home appliances as well. In this paper, problems in the recycling process with regard to the recovery of waste plastic are pointed out.

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We investigated simple methods for the detection of fly ash dispersed at a landfill site based on the observation that fly ash trapped in water increases the electric conductivity of water. Containers with deionized water for the collection of air particulates were placed at 5 sites in a landfill site over 6 weeks, and the electric conductivity of water samples was measured. The relationship between the water samples and the contents of zinc, copper, and lead in the deposited matter was examined. Close correlations between these were noted, the samples collected at the sites had a large amount of particulates and were near dumping sites. This indicates the usefulness of this method. It is effective to the point of 10 mS/m or more in electric conductivity.

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