This study aims to determine the factors behind the acceptance among residents of waste policies by local governments operating incineration facilities. We selected Nagoya City in Japan and Korea’s capital city of Seoul as the target regions for this study. Seoul is presently in an intermediate stage for gaining the agreement of residents for managing incineration facilities near to them, meanwhile in Nagoya, it has already been settled that incineration facilities will be the main method for municipal waste treatment. After conducting a questionnaire survey to explore the opinions and attitudes of residents’ regarding the building and running of incineration facilities, we then analyzed the factors leading to acceptance by the residents in both cities. As a result, it became clear that beyond being concerned with the high risk from pollutants that are discharged from incineration facility, residents are, rather, more anxious about the credibility of the administration at work in the two cities. Also, in the case of Seoul, we found that psychological disgust was a driving factor affecting acceptance of incinerators by residents.

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Japan’s food industries and households combined generate approximately 22,000,000 tons of food waste per year. Currently only about 36% of this waste is being recycled as fertilizer, feed for farm animals or used in some other ways. The development of novel ways for utilizing this waste is required in order to promote its recycling. In this study, we have developed a procedure that can utilize food waste as the culture medium for Bunashimeji mushroom (Hypsizygus marmoreus). We compared raw kitchen waste (vegetable scraps), cooked waste and banana pericarp as the culture media. Among these, the culture medium prepared from raw kitchen waste was the most appropriate for mycelium growth, while all types of waste were useful in the fructification process. Furthermore, fructification was successful when we used frozen mycelia and culture media from vegetable scraps, which suggests the possibility of developing a mushroom cultivation kit. These results provide insight into a novel utilization of food waste that not only increases recycling, but also produces a high -value-added commodity.

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The use of supercritical water to recover iron oxides from oily mill sludge emitted by the steel industry was examined. Using supercritical water oxidation treatment, more than 95% of the organic materials contained in the sludge were removed, and they could be degraded completely to CO₂. In addition, there were indications that iron oxides catalyzed the oxidation reactions of organic materials. Using supercritical water treatment without oxygen, some of the organic materials were removed from the sludge. Iron oxides contained in the sludge were oxidized to Fe₂O₃ with the existence of oxygen in an amount in excess for the oxidative degradation of organic materials. On the other hand, reductive materials were formed when the amount of oxygen was less than the stoichiometric amount by partial oxidation of organic materials, and it was possible to reduce Fe₂O₃ to Fe₃O₄. These results suggest that the efficiency of treatment and the conditions of recovered iron oxides are influenced by the interactions between iron oxides and organic materials in supercritical water, and show the prospect of using supercritical water as a novel method for the recovery of inorganic resources from organic-inorganic mixed wastes.

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Production volumes for waste molten slag have seen an increase along with the increased use of waste melting furnaces. To seek novel applications for this slag, we first examined its influences on microbial growth. For Escherichia coli, the addition of slag inhibited growth by approximately 80% under static culture conditions, however under shake culture conditions there was no significant effect. Similarly, the growth of aquatic microbes from fish aquariums was also inhibited by about 80% with the addition of slag under static culture conditions. Results show that the slag could possibly be utilized as a preservative for tropical fish aquariums and in vases for cut flowers, which like static culture conditions. We then set out to assess whether the slag could actually be used in this manner : when slag was added to aquariums with neon tetras, the occurrence of algae was not observed over a period of three months. In addition, an antiseptic effect was witnessed when slag was added to vase water holding cut chrysanthemum flowers, and it was possible to extend the freshness of the flowers up to 1.7 times longer than those in the control vases. As the addition of slag did not show any negative effects on the survival rate of the neon tetra fish or the seven different varieties of cut flowers in the vases, we have concluded that waste molten slag could be made available for use as a preservative in aquariums and flower vases.

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Fuel cells are composed of separators (metals such as Fe), electrolytes (polymeric materials), electrodes (carbon) and catalysts (metals such as Co, Ni). Leaching of Co, Ni, and other catalytic heavy metals from waste fuel cells poses possible environmental risk during dumping. The aim of this study was to investigate whether the hazardous chemical substances dissolved into water from a fuel cell catalyst could cause acute toxicity effects. The individual Co and Ni toxicity to the green alga Pseudokirchneriella subcapitata (P. subcapitata) was investigated. Acute 72 h growth inhibition assays with P. subcapitata were performed according to the OECD ecotoxicity test guideline TG201. NiCoFe/C fuel cell catalyst was assessed for its leaching properties under low and high pH conditions. Toxicity of Co and Ni in the real fuel cells was also observed with P. subcapitata. Our results indicate that the tested fuel cell catalyst was moderately toxic under the acidic condition.

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This paper shows the need for steel pile sheet pipes with seepage and clarification functions on vertical cutoff walls used in coastal landfills from a long-term perspective. In addition, the possibility of using H-jointed SPSPs with H-H joints and seepage and clarification functions installed in the inner spaces of H-joints is considered, and their hydraulic conductivity was evaluated by laboratory hydraulic conductivity tests. The H-jointed SPSPs with H-H joints and seepage and clarification functions installed in the inner spaces of H-joints were demonstrated to be a feasible technology. Moreover, the water-shielding capability of H-joints was controlled by coordinating the thicknesses of the water-swelling sheets.

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