Japanese modern waste management started for the purpose of keeping “public health” extended the role to “environmental conservation” and “proper treatment”, corresponding to the economic growth. Establishment of a “sound material-cycle society” becomes the target of waste management to solve the global environment problem and to build “sustainable society.” “Reduce, Reuse and Recycle” are major contents of the policy for sound material-cycle society, but 3Rs should involve not only waste management but also resources conservation. The information of 3R should be fed back to design and usage of products.

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The term sound material-cycle society (SMCS) is intended to integrate environmentally sound management of solid wastes and efficient use of material resources, and it is sometimes expected to imply long-term vision of a society toward sustainable development. Japanese practices for SMCS have had good progress in general, whereas obstacles such as conflicts in cost sharing among stakeholders and influences of increasing resource demands by neighbourhood developing economies are revealed. Research perspective to fill the gap between the concept and the practice of SMCS is discussed. Relation between material flows and material stocks is essentital in the field of civil engineering.

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This study investigated a desirable garbage recycling system consisting attributes such as number of times for garbage collection, collection methods, charge and so on, using a conjoint analysis as multi-attribute utility analytical method, which differs from conventional questionnaire investigations to evaluate each attribute independently. Especially, the conjoint analysis was applied to residents in three local municipalities which are different in regional conditions such as the current treatment way of garbage, the urban form such as urban or rural areas, and the type of habitation. As the result, willingness to pay (WTP) for the number of garbage collection time was high for residents living in collective housings. In a large city, biogasification which can recover energy tended to be more desirable than composting.

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In this paper, Waste Input-Output analysis to focus on the advanced loop-closing technologies in the steel production was exercised to evaluate the material flow and environmental loads due to the technological changes; several scenarios were designed to develop the industrial eco-system through the introduction of an advanced loop-closing technology, which utilizes the industrial wastes as a natural resource substitute, and the reduction of natural resources input and the improvement of resource productivity were identified.

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In the Kashima Bridge constructed in 1978, about 40 % of stirrup steel bars of pillow beam fractured due to the excessive ASR expansion. For this reason, the pillow beam was completely reconstructed by removing all the concrete. In order to recycle concrete rubbles obtained from the Kashima Bridge, the residual ASR reactivity of recycled aggregate concrete was examined in the expansion test under accelerated curing conditions. From the results, it was found out that ASR expansion behavior of recycled aggregate concrete was almost similar to that of concrete with original andesite stone, and that the 15% fly ash replacement or B-type blastfurnace slag cement was not effective in controlling ASR expansion.

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The 3Rs (reduction, reuse and recycling), which aim at saving natural resources and reducing environmental loads, are one of the major challenges for sustainable development in the world. For the promotion of the 3Rs, it is important to take into account social and economic conditions of each country, such as demand for recyclable resources from manufacturing industries. Environmentally sound management of waste is a first step towards the promotion of the 3Rs in any country.
According to a questionnaire survey made to governmental officials in Asian countries, most face challenges related to medical and packaging waste. Also, there are problems with water and air pollution arising from waste management and recycling processes, as well as difficulties in developing the necessary institutional, financial and technological capacities. Through implementation of international cooperation projects and institutional and technical support for waste reduction, Japan can play a significant role to respond and overcome problems specific to each country in Asia.

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High transportation cost associated to waste recycling necessitates the improvement of the current reverse logistics system. Based on the analysis of the characteristics and present status of reverse logistics in Japan, this study suggests a system using cooperative transportation and transport mode shift to increase efficiency of logistic activities. This article presents a model using genetic algorithm to evaluate the effect of the proposed reverse logistics system. The simulation results show that the system is effective for reducing transportation cost.

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The phosphorus contained in excess sludge could be a 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 them are discharged out as the excess sludge. Therefore, in many phosphorus recovery processes, a method combined subcritical water process with magnesium ammonium phosphate (MAP) process had introduced to be able to get high solubilization rate and high phosphate recovery rate. In this study, excess sludge collected from a sewage plant of Ube city, Yamaguchi prefecture was applied to subcritical water process. And experients by changing the molar ratios of Mg/P and determination of optimum operating parameters of MAP process were carried out. In the experiments, as known, the solubilized sludge contained Mg²⁺, which released from the excess sludge. And, it is found that the molar ratio to recovery MAP was 1.0, if the addition of Mg²⁺ was taken into account.

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The amount of sewage sludge produced in municipal wastewater treatment plants in Japan increases with the increasing population every year. Hence, the introduction of the solubilization of sewage sludge is being hastened. In many solubilization processes, high-speed rotary disk process has became the center of attention for the characteristics of easier control, maintenance and expectation of cost reduction. Therefore, in this study, high-speed rotary disk process was applied to solubilization of excess sludge from a sewage plant of Ube city, Yamaguchi prefecture to examine optimum operational conditions. As the results, with anaerobic treatment, the solubilized sludge from high-speed rotary disk process could shorten digestion time until 10 days. And more, applying the solubilized sludge from high-speed rotary disk process in activated sludge process, the excess sludge produced from the settle tank could be reduced 60 %. In addition, when comparing with other solubilization methods (ultrasonic process and subcritical water process) to evaluate utility of high-speed rotary disk process, as the results, electionic consumption of high-speed rotary disk process was superior to other solubilization methods.

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Aichi Prefecture produces the largest amount of natural silica in japan, approximately 70% of the nation's total production while at the same time discharging a considerable amount of ceramics by-product. As the disposal of ceramics by-product has recently become an apparent problem, it has begun to affect the production of ceramics. The need for recycling of the by-product is growing. The case study in this paper focuses on the construction of the EXPO 2005 AICHI JAPAN Fujioka Parking Area. The fine grain silica sand, which had previously been buried underneath the parking construction site, was crushed and mixed with diffusion with gravel, which had also been disposed of in the same area. With the introduction of the ‘crushing and mixing with diffusion’ technique, the fine grain silica was 100% recycled. In another example, for the pavement of the Bus Terminal, the grain silica sand, aggregate and cement were crushed and mixed with diffusion, and hybrid pavement material was produced. This hybrid material has two contradictory positive characteristics at the same time, water-retention and ground water increment functions to prevent head island effect, and permeable pavement function to reduce traffic accidents.

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Concerning environmental load reduction effect from the commercial buildings, the method for evaluating multiple effects of environmental load reduction countermeasures was constructed. In particular, we built a model about CO₂ emissions. The model made in this research combines building energy load model, air conditioning system evaluation model and building stock quantity stochastic model. This model incorporated the module to calculate CO₂ emission of constructing buildings and demolishing buildings. This model can calculate the CO₂ emission of commercial building sector of Japan. Using this model, we evaluated the difference of the CO₂ reduction effect according to scrappage rate of buildings under various CO₂ reduction countermeasures in buildings.

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The characteristics on waste disposing behavior and the amount distribution of municipal combustible waste were analyzed, which was based on the amount distribution of waste bag in one district in Fukuoka city, Japan. The weights on the waste bag were measured to clarify the actual status on the waste disposing. As a result, any people reduce the waste disposing frequency not from the bother on the waste disposing but from the adjustment of the amount of waste bag. Many people decide the size of waste bag in advance based on the amount grasping from the long time experience. The unit weigh on waste bag was recognized 0.10 - 0.12 kg/L as full.

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In this study, we comprehensively evaluated greenhouse gas (GHG) emission, terminal waste disposal and waste disposal cost related to municipal solid waste (MSW) treatment based on lifecycle inventory (LCI) analysis. Our evaluation considered multiple scenarios combining numerous MSW intermediate processing options. Material recycle of plastics was estimated to reduce 10% of GHG emission of the basic scenario in 2004. Also composting kitchen scraps was estimated to reduce 7% of GHG emission. Though thermal recovery by MSW incineration and/or methane fermentation of kitchen scraps was estimated to increase 9 to 12% of GHG emission, terminal waste disposal and waste disposal cost on the thermal recovery scenario could be lower than those on the material recycle scenarios.

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Correspondence concerning 3R at the life level is late though the correspondence of 3R is materializing at a nation and a corporate level. This originates the fact that it is basic that 3R does an altruistic action that an individual individual environmental behavior.
A lot of citizens participated in the EXPO Eco-money introduced in the Aichi EXPO, and it became a chance to invite the environmental behavior that stuck to life. It reported on the EXPO Eco-money business, and the factor to press the environmental behavior was analyzed in this text based on the questionnaire survey that came to the EXPO Eco-money center.

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As the phosphorus resource is expected to be exhaustible globally, ensuring phosphorus is strongly required. Especially in Japan, there is no domestic production and almost all phosphorus is imported from abroad. Therefore phosphorus recovery from wastewater treatment system where a large amount of phosphorus flows in high concentration is quite important. In this report, characteristics of phosphorus recovery technologies under investigation or in practice are summarized focusing on recovering from wastewater or returned water, sewage sludge, sewage sludge ash, and so on. For the future, three prospects are required as follows: 1. development of whole wastewater treatment system with the application of phosphorus recovery technologies considering other processes, 2. advancement and effective development of technologies based on clarification of phosphorus recovery mechanisms, 3. demand survey and recovered material preparation for utilization of recovered phosphorus as fertilizer, and exploitation of phosphorus recycle route such as substitute of phosphorus rock, or industrial use.

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Quantitative quadrat sampling of macrobenthos was carried out at two tidal flat estuaries in Tokushima Prefecture to study the relationship between physical characteristics of sediments and biodiversity. Conclusions are as follows: 1) Physical characteristics of sediment were classified into 7 groups by cluster analysis in relation to particle size composition of sediment and difference in elevation. 2) There are relationships among plant communities, formation process of tidal flat and stability of the topography. Plant communities determine physical characteristics of sediments. 3) Those groups were also characterized with some specific macrobenthos species. The diversities of sediment characteristics led to increase the number of species. The result suggested that the number of species has a positive correlation to the number of sediment groups.

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Methane hydrate (MH) is expected as a new resource of natural gases. However MH is solid and it doesn’t flow, thus dissociation methods of MH into water and CH₄ gas in oceanic sedimentary layers are proposed. Here we focused on the exothermic reaction of CO₂ hydrate formation for thermal stimulation of the layers. The possibility for raising temperature of the sedimentary layers by the exothermic heat of CO₂ hydrate is considered by following items. 1) A laboratory experiment to measure temperature through CO₂ hydrate formation in a pressure cell. 2) Proposing a numerical temperature-raising model by CO₂ hydrate formation. 3) An estimation of the temperature raising model using unsteady heat diffusion analysis by simulating the results of the laboratory experiment. 3) An analysis considering the boundary condition of sedimentary layers and the estimated model. As a result, the temperature of the layers can be raised by about 9°C using CO₂ hydrate formation. Then this shows a possibility to use CO₂ as a warming material for oceanic sedimentary layers to exploit MH.

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The possibility of reed chip as a carrier material for the thermophilic oxic process was examined by comparing with the cedar chip. The water holding capacity of reed chip (2-3mm) was about 34% less than cedar chip, but the ventilation was about 17% higher than cedar chip. As a result, 6% decrease in water holding capacity and 12% increase in ventilation were realized when reed and cedar chip were mixed equally compared with single use of cedar chip. By using mixed chip of reed and cedar, the average temperature during treatment by the thermophilic oxic process was 10°C higher, resulting in 7% improvement in treatment efficiency and 50% less residual accumulation than those with cedar chip. These results demonstrated an enough possibility of mixed chip of reed and cedar enabling higher treatment performance in the thermophilic oxic process than conventional system.

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Relationships between domestic wastewater pollutant discharge per capita (PDC) and economic development indicators were discussed in this paper. The chronological relationships in Lakes Shinji and Nakaumi area as a case study of chronological relationships showed inverted U-shaped curve, namely environmental Kuznetz curve (EKC), for COD, TN and TP. PDC-COD of forty-seven prefectures in Japan in 2004 spatially had one-order relationship with gross prefecture incomes per capita. However, significant relationships were not observed for PDC-TN and PDC-TP. The regional relationship in the coastal area in developing countries in 1998-2002 showed that there was typical regional relationships between PDC-BOD and PPP-GNI per capita. The relationship between PDC-BOD and PPP-GNI per capita of developing countries in Southeast Asia, Pacific and African Regions with similar climate, water resources and economic condisions showed that PDC-BOD were in wider range when PPP-GNI per capita was smaller and in narrower range when PPP-GNI per capita was larger. The relationship between PDC-BOD and newly introduced water, sanitation and economic parameter (WSEI) in this study showed the same tendency. These relationships were similar to the original Kuznets relationship of income and equity. The transition levels were US$ 3,000-4,000 for PPP-GNI and 1.0 for WSEI, respectively.

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Characterization of Zostera japonica habitat and its effect on benthic fauna were studied. The large seasonal change in aboveground biomass of Z. japonica was observed, though the belowground biomass did not change seasonally. Organic matter in seagrass sediment was higher than that in nearby non-seagrass sediment and positively correlated with the above and below ground biomass of Z. japonica. Species abundance and richness of Polychaete and Crustacea in the seagrass beds were significantly higher than those in non-seagrass area. These results suggested that detritus supplied by blighting the belowground biomass of Z. japonica, and precipitated by wave attenuation due to the increase of above biomass of Z. japonica, became foods for benthic animals and led to increase richness and variety of benthic fauna.

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Arsenic with concentration over the environmental standard was detected in groundwater samples at an industrial property located in the south-eastern part of Matsumoto Basin. Groundwater qualities within and on the periphery of the site were investigated and high content of arsenic was found in groundwater from a deep well. Upon investigation using a bore-hole camera it is turned out that groundwater in confined aquifers contaminated by arsenic was discharging to the overlying unconfined aquifer via a channel of the well pipe with multi-screens and holes opened by corrosion. Three-dimensional, transient, saturated-unsaturated flow analysis using a finite element method was performed and the results were compared satisfactory with observed groundwater tables. The numerical results also demonstrated the pattern of groundwater flow from the confined aquifer to the unconfined aquifer via the well casing. Correlation and Eh-pH diagrams based on the data from the groundwater quality investigation showed that there is a high positive correlation between As and Fe and that the lower Eh, the higher As becomes regardless of pH.

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The fate of di-2 (ethylhexyl) phthalate (DEHP) in water treatment processes was investigated at four water treatment plants in January through September 2004. The result showed that monthly or seasonal variation of DEHP concentrations in raw water was not so large at all of the four plants. DEHP was highly removed in water treatment processes in many cases, and DEHP accumulated in solid samples (i.e., sludge and scum), whose content of DEHP was in the order of 10³-10⁴ μg/kg dry solids. It was also found that most part of DEHP in raw water was transferred into sludge rather than scum at all plants although DEHP content in scum was similar to or higher than that in sludge if compared on dry solid basis. The load of DEHP precipitation from air onto the basins at one of the four plants was estimated to be negligible when compared to its input through raw water.

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Dioxins are accumulated in sediments in port and harbors at high concentrations. Contents of dioxins are regulated in environmental quality standard, while leachability test is required in the reclamation by dreadged materials. This study aimed at the estimation of results of leachability test by content test. The leachability estimated by the content and the ignition loss assuming the equilibrium between the soil phase and the water phase was approximately equal or higher than the actual leachability. The lower experimental leachability than the estimation was due to the detection limit in leachability test.

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The health hazard caused by asbestos has become a serious social issue, and the thoroughness in prevention measures of scattering asbestos becomes an important problem. In this paper, it is attempted to develop a procedure that asbestos can be transformed into non-fiber and non-asbestos by means of heating with the agent for removal or encapsulation of asbestos. As a result, asbestos is made to non-fiber and non-asbestos by heating at 700°C for one hour with the calcium-containing agent. Also the sprayed asbestos and the asbestos-containing cement board can be non-fiber and non-asbestos at the same temperature and time period.

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The health hazard caused by asbestos has become a serious social issue, and thoroughness in prevention measures of scattering asbestos becomes an important problem. Complete removal or careful asbestos containment procedures will be necessary, if sprayed asbestos are found. Asbestos containment is performed in order to reduce or eliminate the risks of asbestos exposure on human health. In asbestos containment, it is very important to confirm the spraying condition. In this study, it proposes the method of confirming the spraying condition by using the fluorescent agent and taking the fluorescent photograph to leave evidence of it.

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