Besides polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs), their derivatives, completely or partly substituted with bromine, iodine or fluorine (PXDDs/PXDFs/PXBs), are known to be present in the flue gas emitted from waste incineration facilities. However, little is known about the emission levels of these substituted compounds in the flue gas. In this study, the emission levels of semi- and non-volatile organic halogens (SNVOXs) were investigated from ten waste incineration facilities. It was found that some facilities emitted semi- and non-volatile organic bromine (SNVOBr) or semi- and nonvolatile organic iodine (SNVOI) 0.02 to 1.4 times that of semi- and non-volatile organic chlorine (SNVOCI) . In addition, PCDDs/PCDFs/PCBs contributed to only less than 1.4 mol% of SNVOCI. These results indicated that many multiple halogen-substituted compounds were emitted together with chlorine-substituted compounds such as PCDDs/PCDFs/PCBs.

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This study focused on how public preferences about choosing a siting plan for a waste disposal facility for wide area management were formed by communication between the local officials and the public. A meeting for discussion between the public and the local officials about a hypothetical siting plan for a waste disposal facility for wide area management was held in Iwate Prefecture. In the meeting, three choice experiments (CE) and information offering or discussions, including questions and answers, were conducted alternately. The results showed that information offering and questions and answers changed public preferences, promoting public acceptance about wide area management of waste and restraining public distrust against accepting industrial waste. This indicates that communication between the local officials and the public in choosing a siting plan for a waste disposal facility for wide area management plays an important role. Moreover, it indicates that public participation in choosing a siting plan for a waste disposal facility at the planning stages restrains public distrust and promotes consensus building.

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At present, most architectural waste is disposed of without recycling because it includes waste wood treated with noxious chemicals. One of the most noxious chemical compounds is CCA, a mixture of copper (Cu), chromium (Cr) and arsenic (As) . CCA combines with polysaccharides such as wood cellulose to form chemical compounds that have low solubility in water, thus, preventing wood corrosion. In this study, we noticed that the copper and chromium that are included in CCA have catalytic activity. We prepared a charcoal sample by carbonization of some wood treated with CCA and examined the catalytic activity for methanol steam reform and characteristics of the prepared charcoal as a catalytic support agent. The methanol steam reform activity of the charcoal from the CCA-treated wood was relatively low, but, immersed in copper solution, the same charcoal showed high catalytic activity.

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Chlorofluorocarbon (CFC-12) was decomposed using two kinds of molten alkaline hydroxides (NaOH and KOH) in without any oxidizing gas like air. During short experiments, operational conditions such as reaction temperature, CFC concentration, and gas flow rates were examined. The CFC-12 appreciably reacted with the molten alkaline hydroxides in an inert atmosphere at temperatures greater than 450°C. Decomposition reached about 70% when 10% of CFC-12 was fed to the reactor at 600°C and at a 500 mL/min flow rate.
Decomposition continued satisfactorily during longer experiments of 24h. Based on these experiments, the authors infer that CFC-12 decomposition occurred according to the following chemical reactions.
CCl₂F₂+6 (Na·K) OH→ (Na·K) ₂CO₃+2 (Na·K) C1+2 (Na·K) F+3H₂O

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In order to utilize the lime cake discharged from beet sugar factories effectively, we studied solidification methods and humidity self-control characteristics. We found that a solidified substance with high compressive strength (ca.19.6 MPa) can be obtained by heating a green compact consisting of lime cake, calcium hydroxide and scallop powder at 150°C in a steam-CO₂ atmosphere. In addition, lime cake has a high specific surface area (32m²/g) and pore radius of 1.5-2.5nm. We investigated the water vapor adsorption-desorption characteristics of the solidified substance. As a result, we consider it to be a candidate for humidity regulating materials and expect its application in building wall materials.

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We investigated the carbon utilized as substrate and the nitrogen utilized as a nitrogen source during composting, to evaluate the C/N ratio based on microbe consumption and the microbe products in compost substrate. We composted a synthetic mixture consisting of cornstarch as a carbon source and ammoniacal nitrogen as a nitrogen source. We carried out the composting process using a small reactor to obtain a temperature rise equal to that of an actual composting size. After the temperature rise, we kept the substrates at 60°C or 65°C until the completion of 10 days composting.
The carbon reduction in the mixture increased linearly, and the conversion of nitrogen into organic nitrogen was unaffected after increasing the first 3 days. As a result, the C/N ratio calculated for microbe consumption was lower than 10 during the early stage, but became over 40 during composting. The carbon yields were calculated to be over 40% during the early stage and became around 12% during the composting process. The observed nitrogen consumption by microbes was 1.17gN·kg_wet0^-1 (60°C) —1.07gN·kg_wet0^-1 (65°C) .

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Domestic and non-industrial wastes have been incinerated to control mass volumes and to stabilize the quality of environment. Incinerated residues including fly-ash are being reclaimed in landfill sites. Fly-ash from waste incineration is known to contain numerous metal species and intact environmental pollutants such as dioxins, PCBs and PAHs. To investigate the toxicity of fly-ash, test solutions extracted from fly-ash, collected from six different sources, were prepared and exposed to freshwater fish Japanese medaka (Oryzias latipes) and marine bivalve mussel (Mytilidae sp.) . For medaka, effects of exposure to fly-ash were assessed by monitoring hatching inhibition, acute lethal toxicity, induction of CYP1A and vitellogenin; for mussel, comet assay (as estimation of DNA damage) and induction of GST activity were monitored. All fly-ash eluate solutions exhibited lethal toxicity to medaka and the LC 50 values (96 hrs) were less than 40% concentration of elutes. Hatching inhibition, delayed hatching, spinal deformity of hatched embryo, inductions of CYP1A activity and vitellogenin were observed in exposed medaka. DNA damage and induction of GST activity were observed in exposed mussel. These results supported our previous study on toxicity of leachate from landfill sites with medaka bioassay. Fly-ash participates in contributing to leachate toxicity. Treated leachate still exhibited ecotoxicity that are released into river. In addition to the conventional methods, more appropriate means for leachate treatment and environmental risk management of waste disposal landfill sites are in need for the prevention of ambient environmental pollution.

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The amount of excess sludge produced in municipal wastewater treatment plants in Japan is increasing every year as the urban population increases. The phosphorus in the excess sludge could be hopeful phosphorus resource since phosphate rock is being exhausted all over the world today. Japan imports much phosphorus from abroad every year but much of it is discharged out as excess sludge. Therefore, the solubilization process, one method of recovering phosphorus from the sludge, could be a promising solution. In this study, the subcritical water process, a new technology that solubilizes sludge under subcritical conditions, was applied before the phosphorus in the sludge was recovered with magnesium ammonium phosphate (MAP) process. As a result, the solubilization rate of excess sludge achieved was approximately 80%. In addition, about 94-97% of the phosphorus could be recovered.

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Since wastes generated by medical care facilities can cause infection, they are designated as specially controlled wastes and attention must be paid to their handling. Intermediate treatments such as sterilization and incineration are obligatory before final disposal at landfill sites.
In this study, we evaluated the safety of intermediate treatment methods for medical wastes, including incineration, steam sterilization, electromagnetic wave sterilization and UV radiation sterilization, using a battery of bioassays and a viable cell count test. We compared the sterilization effectiveness of these intermediate treatments using model microorganisms. In the experimental results, no bacteria or fungi were found in the incineration treatment residues, but they were found in the non-incineration sterilization treatments using high pressure steam, UV irradiation and electromagnetic waves. In the battery of bioassays for toxicity evaluation, inhibition action was observed in the residues of both incineration and non-incineration treatments. However, the incineration ash of paper diapers showed relatively strong toxicity. These experimental results suggest that both the infectious microorganisms and the toxicity of hazardous chemicals persisting in treatment residues should be considered before the final disposal of medical wastes.

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Melted waste PET bottles that have been spun into polyester fibers cause coloration and thread breakage problems. The causative chemical agents and process had not been identified because analytical methods for waste PET bottles contaminated with several impurities had not been developed. We examined the relationships between the chemical cleaning and melting processes, the quality deterioration of the recycled products, and impurity removal processes including the polishing of waste PET bottles. We obtained the following results.
Sb in the residual polymerization catalyst and Na compounds in the cleaning agent and the impurities are oxidized in the melting process, causing the coloration of polyester fibers. Moreover, contaminated inorganic matter causes blockages in the spinning filter that cause thread breakage.
Selective physical polishing of impurities that are difficult to remove with chemical cleaning decreases the contamination of inorganic matters. The impurities are removed uniformly when the polished amount is increased, reducing the formation of coloring precursors. However, the balance of impurity removal effect and the amount of polishing should be considered because the amount is inversely proportional to the selective removal of impurities.
The prospect of producing high quality recycled PET products is enhanced through the introduction of polishing into existing recycling processes.

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