Journal of the Japan Society of Material Cycles and Waste Management
Online ISSN : 1883-5899
Print ISSN : 1883-5856
ISSN-L : 1883-5856
Volume 20, Issue 2
Displaying 1-5 of 5 articles from this issue
Paper
  • —Present Situation and Analysis of Environmental and Economic Effects—
    Tomohiro Tabata, Tomohiko Ihara, Hiroshi Nakazawa, Yutaka Genchi
    2009 Volume 20 Issue 2 Pages 99-110
    Published: 2009
    Released on J-STAGE: June 30, 2009
    JOURNAL FREE ACCESS
    In order to better understand the amount of self disposed waste materials, and what methods are generally being employed, we conducted a survey in central Iwate Prefecture on the composition of household waste. Our survey results indicate that the main method of self disposal is composting; measuring in at approximately 90 grams/person/dayby 2.6%. We then evaluated both environmental and economic effects of waste self disposal from the viewpoint of MSW management systems. In this evaluation, regional property of household waste disposal and the waste treatment structure had to be taken into account. Results show that, compared to the current scenario, the promotion of non-electric composters decreases GHG emissions, with final disposal lessened by 6.2% and a decrease of 6.5% in treatment costs seen. By contrast, the promotion of electric composters brings certain disadvantages with regard to GHG emission, SOx and NOx emissions, and treatment costs.
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  • —Simultaneous Detoxification and Waste Destruction—
    Ryo Tachino, Tomoya Nonoue, Yoshito Oshima
    2009 Volume 20 Issue 2 Pages 111-118
    Published: 2009
    Released on J-STAGE: June 30, 2009
    JOURNAL FREE ACCESS
    Currently, over 90% of medical waste in Japan is treated at off-site facilities where incomplete treatment and illegal dumping is highly likely. This study proposes a novel detoxification treatment for medical wastes, specifically infected plastic syringes, using supercritical water oxidation (SCWO).
    We conducted SCWO of polypropylene (PP) microtubes, disposable plastic syringe and evacuated blood collection tubes selected as model medical disposable wastes. Experiments were conducted in a compact batch reactor at 450°C and 25MPa. Results showed that not only the single component sample (PP) but also multiple component samples (disposable syringes with needles attached and evacuated blood collection tube) were decomposed successfully except for their metal parts. In addition, Escherichia coli (coliform bacillus) were eliminated simultaneously with the PP decomposition. These results confirm the prospect of employing SCWO systems for practical applications in the treatment of infectious medical wastes.
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  • Sayaka Ita, Koji Takase, Yasushi Kondo, Ayu Washizu
    2009 Volume 20 Issue 2 Pages 119-132
    Published: 2009
    Released on J-STAGE: June 30, 2009
    JOURNAL FREE ACCESS
    In an effort to bring about the promotion of sustainable consumption, a thorough evaluation of those environmental impacts that are either directly or indirectly linked to households and lifestyle is a key concern. Daily food habits are closely linked to overall household consumption and largely affect environmental conditions. In Japan, where eating trends have changed dramatically over the last thirty years, more and more consumers are opting to replace home-cooked meals with already prepared take-home meals, frozen/pre-packaged meals for re-heating, or dining out instead. These changes in the consumer dietary lifestyle have a certain degree of negative effects on the environment. The extension of the Waste Input-Output (WIO) model was applied with the aim of evaluating the environmental impacts of such changes in dietary habit; and the impacts related to carbon dioxide emissions, landfill content, and energy consumption have thereby been determined. Results indicate that meals cooked at home are the more environmentally friendly meal. In terms of carbon dioxide emissions and energy consumption, home-cooked meal replacements have the greatest impact on the environment; and in terms of landfill space, the habit of dining out holds the greatest adverse impact. These results encourage us to promote the idea of a return to home-cooking as a means for achieving a more sustainable system of consumption.
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  • Tetsuya Otake, Rei Ota, Masahiro Shishido, Norio Andoh
    2009 Volume 20 Issue 2 Pages 133-140
    Published: 2009
    Released on J-STAGE: June 30, 2009
    JOURNAL FREE ACCESS
    Every year, 4.6 million tons of architectural waste wood is collected, and its recycling rate, including thermal recycling, is only about 60%. We examined the preparation of cooking charcoal from waste wood charcoal as a new means of utilization. In general, the combustion rate of charcoal is strongly affected by its specific surface area so that a heavy charcoal, such as bincho charcoal, burns moderately and offers favorable control over combustion heat. In contrast, the charcoal from architectural waste wood burns faster because it is predominantly composed of coniferous tree wood, which has lower density and larger specific surface area.
    In this study, briquettes with high densities were prepared by molding and calcination of the charcoal powder from coniferous tree wood through the addition of some binders. Then, the burning characteristics of the briquettes were evaluated. Wood tar and waste saccharine were used as the binders. The briquettes obtained this way had high density, high mechanical strength and improved burning characteristics equivalent to those of bincho charcoal. In addition, the mechanical strength and burning characteristics of the prepared briquettes were revealed to be strongly influenced by the properties of the chars derived from the binders.
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  • Tohru Futawatari, Naoko Sakamoto, Suehiro Otoma
    2009 Volume 20 Issue 2 Pages 141-149
    Published: 2009
    Released on J-STAGE: June 30, 2009
    JOURNAL FREE ACCESS
    The Japanese Ministry of Agriculture, Forestry and Fisheries is furthering the progress of its biomass town plan for the promotion of effective biomass use throughout the country. It has not yet, however, been effective enough. The study, which focuses on environment and economics, has developed an analyses and evaluation for biomass utilization systems in the Kyushu region: Ooki Town, Kobayashi City, and Hita City, all of which are taking part in this Ministry plan. The results are being applied in order to identify if there is a possibility of establishing an effective biomass utilization system in Wakamatsu’s urban area of Kitakyushu City.
    Biomass utilization is estimated to annually reduce emission amounts of CO2 to 3.1, 529.2, and 181.2 CO2 for Ooki Town, Kobayashi City, and Hita City, respectively. The analysis indicates that the composting of livestock excrement is a very effective way to reduce CO2 emissions, as long as enough demand for the compost exists in the area. Economic evaluations varied widely for such systems.
    A simulation for the Wakamatsu area showed that an amount of 311 tons of CO2emissions were reduced through the introduction of the biomass utilization system. This implies that biomass can be effectively used even in an urban setting, where only food waste is available as the main biomass resource.
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