The future of energy-consuming steel-making industry strongly depends on the improvement of eco-efficiency; that is, more products except a steel by less input energy. This paper describes a feasible study of symbiotic steelworks with anew heat recovery concept using endothermic chemical reactions. The results revealed a merit of heat recovery of molten slag by using themmal decomposition of limestone for producing a cement clinker from viewpoints of reducing energy consumption and carbon dioxide emission.

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To prevent water pollution by fish cultivation and to achieve the higher fishery production, a zero-emission model for fish cultivation was studied experimentally in combination with plant water-cultivation. This model was an ecological route of material flow from feed to plant (harvest) through fish (harvest), lost feed and excreta, microorganisms and salts. The experimental facility was composed of fish cultivating pond, bio-reactor to purify water and plant water-cultivating pond among which the water was circulated. To prevent propagation of algae which hinder the plant growth, ultraviolet ray was applied the circulating water. Hibuna, Carassius auratus, and water lettuce, Pistia stratiotes, were cultivated as models of fish and plant. The load of feed for fish was compensated by intake of materials by the lettuce and the pond water was maintained to be of a good quality. The material balance has been analyzed and the ability of lettuce for water purification has been determined as to be 147kg-wet biomass/m2/year, 531 g-N/m2/year an 1 l g -P/m2/years in April.

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Construction of infrastructures such as highways generates huge volume of various by-products. In the present study, an estimation system of the emissions, including those from other related economic activities, for a life cycle of an infrastructure project has. been developed. The main part of the system is an extended Input-Output model, which deals processes of construction material production and by-product recycling. The system was applied to alternative route plans of a highway development, and it was revealed that the amount of final wastes are strongly depend upon the types of road structure.Reusable aggregates collected from the road works has been estimated by asystematic method based on statistical data. It suggests that in the near future the quantity of aggregates collected will supply a demand for road works.

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The most effective component was studied in order to predict the potential of recovery resource from organic solid waste. Eight organic solid wastes were tested by three recycle methods. Three methods were the direct use as solid fuel, the methane recovery after fermentation, and the glucose recovery by enzymatic treatment, and the combination of methods was also tested. The recovery quantity of heat as solid fuel and methane can be estimated by the percentage of organic material in the waste. The glucose recovery was not high in case of enzymatic treatment and good indicator was not found for prediction of the reuse potential. However, enzymatic treatment can be used as pre-treatment for other two recycle methods. Furthermore the combination of recycle methods improved the acquired resource and reduced the waste.

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Construction of database based on analysis of materials and energy on industries and processes can be expected to provide heuristic information regarding the possibility of materials and energy circulation through data combination in the database. Thus, in this study, we have developed software called "Materials Cycle Simulator", to suggest the technologies reducing the environmental load. The software can simulate the flow of the raw materials and scrapped material in a local community. The software uses unit information on input and output of materials and energy in each production process and material conversion process, which is derived from individual facts in material-cycle database. The simulator proposes all possible combinations of unit information, i, e., zero-emission networking based on the database.

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Supercritical water oxidation was applied to the destruction of various wastes such as sewage sludge, alcohol distillery wastewater of molasses, .and shochu (rice spirit) distillery waste, and dog food as a garbage simulant. The reaction was carried out in a batch reactor with hydrogen peroxide as an oxidant in the temperature range of 673-823 K. Acetic acid and ammonia are found to be refractory intermediates in supercritical water oxidation of organic wastes. Total organic carbon (TOC) and ammonia concentration produced during the reaction were measured as a function of reaction time. The kinetic data were analyzed by a first order reaction model. Two generalized models including refractory intermediate such as acetic acid were developed and applied to the data analysis.

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We conducted a life cycle assessment (LCA) inventory analysis for input of raw materials, output of products, input of utilities such as electricity, gas, oil and water and various emissions concerning solid wastes in a beer brewery process and wastewater and evaluated environmental impact on global warming based on the cumulative CO₂ emission unit. Namely, the effect of energy recovery due to electric generation by a fuel cell using biogas from methane fermentation of wastewater on the cumulative CO₂ emission unit for the product was evaluated. Also, the effects of methods of treating beer lees on the cumulative CO₂ emission unit i.e., combustion, drying, methane fermentation, converting into livestock's feed or composting, were also estimated. In a beer brewery factory, the amount as much as 48.3% of the cumulative CO₂ emission unit charged on the product beer is found to be due to utilities such as water, electricity, gas and kerosene. These results show that important thing is how to reduce the energy input from the outside via recovering of energy from organic wastewater and solid wastes. It. is found that in the beer brewery factory, the electric energy recovered by the methane fermentation-fuel cell system saves 9.74% of the total electric consumption and it reduces about 2.31 % of the total cumulative CO₂ emission for the product beer. It is also found that the combustion of beer refuse, utilization of beer refuse as livestock's feed without drying or composting of beer refuse does not increase the cumulative CO₂ emission unit for the product beer. Also, it may be pointed out that if the organic carbon of the beer lees could be effectively converted into biogas by methane fermentation as well as that in the wastewater and the biogas could be converted to electricity via a fuel cell, about a 59.8% of total electric energy in the utilities would be saved.

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To establish material recycle society oriented for zero emission, it is important to optimize regional material cycle, to make efficiency of resource consumption rise and to minimize environmental load To construct industrial network, that waste generated from an industry is used the other industries, is needed. In this study we develop a tool to design the industrial network. The tool consists of (1) estimation regional elemental flow (2) design the industrial network using elemental composition of waste. This tool can also estimate waste reduction by the network. From results, this tool can select existed recycle as industrial network candidates. We apply this tool to Aichi prefecture and estimate possibility of waste reduction by industrial network.

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In order to establish a material recycling oriented society to achieve zero emission, analyzing current regional material flow is needed. The analysis is an important key to optimize regional material cycle to make efficiency of resource consumption rise and to minimize environmental load. Various methods in estimating industrial material balances have been tried However, those methods are not very realistic because they require a lot of time and effort. In our study, we developed a simplified method when analyzing regionally, the current material flow using an Input-Output table, and we applied this method to the industries in Aichi prefecture, Japan Because the input output table shows cash flow among industries, making a proper parameter could convert cash flow to material flow. This method is used to estimate input, output and waste generation of all industries. Results show that this method also estimates waste generation and waste ice of each industry. Then we discuss some measures to encourage the recycling of waste.

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Food production and consumption must be in natural material cycle in order to create the zeroemission society. Minimum requirement of amble land area in order to create zero-emission society in Japan is discussed from the concept of nitrogen balance. Appropriate agricultural technologies to sustain zero-emission society are also considered. Since food self-sufficiency rate in Japan is quite low, it is difficult to create zero-emission society. It is impossible to create zero-emission society by improving efficiency of recycle technologies. Zero-emission society must be discussed with the agricultural and food self-sufficiency policies in Japan

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In order to realize a social system with sustainable development, it is necessary for local communities to construct inter-industries material circulation network. In this aspect, wastes evolving from the industries are defined as unused materials. This study suggests a methodology of constructing networks among different industries for reusable materials. Two types of databases are made by means of industrial surveys. One of the databases reveals information about raw material, products and wastes, which is received or emitted on each company of industries in a subject community. The second database defines conversion technologies that enable to transform the wastes into reusable materials. Based on the databases, a network simulator program can analyze material flows in the community. In this paper, Higashi-Mikawa area in Aichi Prefecture was chosen as a model of local community, and the databases of the industries and wastes treatment companies were made, furthermore the material flow for. selected wastes were simulated. Additionally, one suggestion about optimum material circulation network in an application of proper conversion technology is hypothetically designed.

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