Objective. The recycling of food waste by biogasification and/or composting is under consideration by some domestic municipalities. At the same time, a reduction in lost food such as leftovers improves self-sufficiency in food and reduces greenhouse-gas (GHG) emissions from the production, distribution and cooking (referred to here as ‘supply’) of the food. But if food loss is reduced, the GHG reduction effect obtained by recycling will be small. In this study, we investigated the amount of food loss in household waste in Kyoto City, and GHG emissions from the supply of the food. On the basis of the results, we conducted a life cycle inventory (LCI) analysis to clarify the trade-off between recycling by biogasification and reduction in food loss. The functional unit is treatment of 218,510t household waste, including lost food, and the supply of the lost food. Results and Discussion. First, this study showed that the amount of food loss is about 20kg/capita/yr. Of this, 8.3kg was directly discarded food and 11.9kg was leftovers. Second, the GHG emissions associated with the supply of this food were estimated. For directly discarded food, it was an average of 1,402g-CO2eq/kg. For leftovers, it was an average of 1,728g-CO2eq/kg. Accordingly, GHG emissions for food loss are about 32kg-CO2eq/capita/yr. LCI analysis revealed that if biogasification were introduced, the elimination of all food loss would cause a decrease in the substitution effect of about 3,000t-CO2eq/yr. But at the same time there would be a decrease of about 46,000t-CO2eq/yr from the production of the lost food. This result shows that a reduction in food loss would be effective even if biogasification were introduced. Conclusions. Although there is some uncertainty in the results, this study shows that a reduction in food loss would be effective and important for GHG reduction. On the basis of the study, we hope that reduction in food loss will be further promoted.
Objective. In this work, a dynamic material flow analysis (MFA) for glass in Japan in the period of 1978-2008 was conducted to estimate the stock in-use of glass and their recycle potentials. Glass was categorized into glass bottle, glass sheet, and glass fiber products. Time series data about the consumption of the glassware in end-uses, i.e. automobile, buildings, machinery, etc. were estimated. Then, the dynamic MFA for each glassware was conducted, in which the life time distributions for the end-uses were taken into account. A top-down approach and a bottom-up approach were used to estimate the stock in-use of glass. The results obtained by both approaches were compared to validate the data used for dynamic MFAs. Results and Discussion. It was estimated that the stock in-use of glass sheet in buildings and automobiles were 30 million tons and 2.5 million tons in 2008, respectively. The results obtained by the top-down approach and bottom-up approach were moderately coincident during the investigated period. The amount of glass contained in end-of-life products in Japan has monotonously increased during these decades. The glass sheet was the largest among the discarded (landfilled) glass, which was 634 million tons in 2008. Conclusions. Our results showed that there is a substantial stock in use of glass, especially, glass sheets in buildings and automobiles. Further work shall be done to investigate the technological and economical feasibility of recycling glass sheets from the end-of-life products as well as the reduction potential of environmental impacts by the recycling of glass sheets.
Objective. In order to evaluate environmental loads, we studied the effects on energy efficiency and CO2, SO2 emissions in each advanced thermal power generation technologies in China and India using the energy chain life cycle assessment (LCA) model. Integrated coal gasification combined cycle (IGCC), ultra super critical power plant (USC) and natural gas combined cycle (NGCC) were chosen as new power generation technologies. Results and Discussion. NGCC with a natural gas pipeline for transport is most effective in reducing CO2, SO2 emissions. Advanced coal-fired technologies are advantageous in lowering the fueling cost. IGCC and USC are desirable for Shanxi which is the coal producing region. The cost of CO2 emission reduction that will be generated by NGCC amounts 102 USD/t-CO2 in Shanghai province, which is lower than the comparable cost of 492 USD/t-CO2 for the case of IGCC with coal transportation by truck. Conclusions. NGCC with pipeline transportation has a higher energy profit ratio (EPR), and NGCC with a natural gas pipeline for transport is most effective in reducing CO2 emission. From the results obtained by evaluating the energy cost, it was found that IGCC and USC are advantageous in lowering the fueling cost of coal. Meanwhile, the energy cost in natural gas-fired power generation depends on the fuel transport method. The fuel transport cost is high when LNG trucks are used over long distance: hence, developing natural gas pipelines would be most important.
Objective. Results of life cycle assessment on infrastructure include large uncertainty because of its long lifetime and the difficulty of scenario setting. This study aims to propose an “environmental assets management method” for managing such uncertainties with the LCA on infrastructure, and especially explains the treatment of time. Results and Discussion. Several problems have been pointed out for the “lifetime method”, which fixes lifetime of objective goods or service, and total amount of the environmental load during lifetime is evaluated (normally carried out for LCA). It is difficult to set the maintenance technology or situation in long term use of the transport system and it is one of the main factors of uncertainty. Instead of the lifetime method, the “discount rate method” in which the amounts of environmental loads occurring in the future are discounted is proposed. However, it is also difficult to scientifically determine a value of discount rate that can be applied to CO2 emissions calculation. “Environmental assets management” as an alternative framework for assessment in which emissions calculation. “Environmental assets management” as an alternative framework for assessment in which cash flow method, the rates of return for cases are analyzed, in which an up-front investment produces a benefit in the future, such as in real estate or securities. An environmental yield rate (EYR) indicator determines whether it is possible to recover the “investment for environmental improvement”. A method for examining when and what to invest is described. The method can analyze: 1) when to renew after entering service stage, 2) the timing to start the objective project, 3) what to provide. Conclusions. The methodology is applied to provision project of the light rail transit (LRT) and some other modes. It is concluded that the temporal environmental assets management method enables us to evaluate various types of “investment for environmental improvement in the future” projects without setting the lifetime or the discount rate. Also, since the unit of index is either [years] or [%], it is possible to compare projects with completely different scales and types.
Background, aim, and scope. To achieve sustainable development in industrial processes, attributed chemical risks as well as environmental impacts should be managed. Such non-monetary issues have been analyzed by scientific assessment methodologies such as various risk assessment (RA) and life cycle assessment (LCA) procedures. Local risks to be addressed in RA are microenvironments, including the workplace and neighborhood. Although a comprehensive interpretation of such risks is necessitated in industrial decision making, no practical method has been developed to interpret various types of risk with sufficient understandings of plant-specific functions and constraints. Because elaborate model-based approaches are inevitable for practical process development, actual case studies on chemical risks and detailed plant-specific functions and constraints should be performed. Manufacturing processes require that metal parts must be cleaned in preparation for surface treatments or the completion of metal processing. The significant amount of cleansing agents utilized in cleaning processes has become an issue in Japan. Almost all cleaning processes in Japan are carried out by small- and medium-sized enterprises (SMEs). Machinery processes have not been systematically analyzed in terms of chemical risks and, in addition, the environmental management skills of SMEs are generally far behind those of large enterprises. The objective of this study is to reveal the relationships between chemical risks and plant-specific conditions for a practical risk reduction carried out by industrial decision makers. For this purpose, we aimed at the analysis of such relationships in metal cleaning processes. Through this analysis, the correlation between local risks and global impacts were discussed in terms of plant-specific conditions. Materials and methods. Through several investigations on cleaning processes, plant-specific functions and constraints were determined with process data required for plant-specific RA and LCA. By plant-specific RA, workers’ and neighbors’ health risks of inhalational exposure to the utilized cleansing agents were evaluated as unit exposure amount [mg・kg−1・day−1] and total exposure amount [mg・day−1] in the workplace and neighborhood. As global environmental impacts, human health impacts were evaluated by LCA using disability-adjusted life years (DALY) through the life cycle of process chemicals including cleansing agents and utilities. On the basis of evaluation results, the relationships among plant-specific conditions and the results were analyzed and discussed by using the results of regression analyses and the Akaike information criterion (AIC). (View PDF for the rest of the abstract.)
Background, Aim and Scope. In 2007, China became the world’s most CO2 emitting country. China’s CO2 emission keeps increasing along with its high GDP growth rate reaching the average of nearly 10% over the past decade. From the perspective of global warming prevention, this study uses input-output tables to reveal the structural change in Chinese economy and the mechanism of CO2 emission by industry sectors. Methods. This study uses input-output tables of the National Bureau of Statistics of China to create linked input-output tables for 1997, 2002, and 2007. The linked input-output tables are converted into tables for environmental analysis by taking account of the energy consumption among industry groups. The converted tables are used for an estimation of CO2 inducement due to changes in the net final demand (domestic final demand and net exports) for each of the 3 different time points. Further, this study analyses the effect of trade on CO2 inducement by treating imports as the competitive type and assuming that imports and exports are produced under the same manufacturing technology available in China. Results and Discussion. Between 1997 and 2002, the CO2 emission increase was small, but the emission increased by 95% between 2002 and 2007. On the other hand, the CO2 inducement intensity decreased in most of industries due to the advancement of energy-efficient technology. The fixed capital formation accounts for a large part of the increase in induced CO2 from the domestic final demand. The final consumption is distinguished between rural area and urban area, and the study finds that the increase in induced CO2 is small for the rural consumption and large for the urban consumption. Secondary industry grew rapidly, and there is a rapid increase of induced CO2 in the industry. As trade grows, CO2 emission increases in China and in its trading partners. The induced CO2 from exports is increased and it accounts for nearly 33% of the induced CO2 from the final demand (domestic final demand and exports) in 2007. The induced CO2 from imports notably exceeds that from exports for mining industry and chemical industry, indicating that CO2 is induced more in import-producing countries than in China. It indicates that China has a tendency to import parts, materials, and minerals produced in these industries and assembles them to produce exports. Conclusions. Having abundant coal reserve, China heavily relies on its energy source to coal, which has a high CO2 emission factor. The issue of global warming is accelerating new innovations in the direction of using clean energy, and China’s future tasks are reducing its coal dependency and increasing the energy efficiency for sustainable development.
Objective. Social impact assessment is advocated as one of the three pillars toward sustainability. In the past, several attempts have been carried out to assess the social impact on the country level. The Genuine Progress Indicator (GPI) and the Human Development Index (HDI) are well known as socioeconomic indexes. However, there are still few studies for the development of the method of social impact. This study is aimed at the development of the social impact assessment method for product life cycle technique using HDI. Methods. HDI is the general index that covered the following three components of human society; education, health and quality of life. We considered the linkage from the inventories (added value, water use, CO2) of the product to the components of the HDI. Social impact factors developed in this study enable us to connect inventory data to HDI. The change of the HDI by the input of these inventory data can be regarded as the result of social life cycle assessment (SLCA). Results and Discussion. Three lists of social impact factor were calculated for each country based on the SLCA method. Added value factors ranged from the magnitude of 1.4×10−6 to 2.4×10−3 (HDI/US$/p), the score of developing country are higher than that of developed country. Water factor was calculated as a negative impact from 1.5×10−5 to 6.4×10−3 (HDI/m3/p), countries with little water resource have higher score. With regard to CO2 factor, the total HDI loss of the whole world caused by CO2 emission was calculated as about 1×10−16 (HDI/kg). Conclusions. A social LCA methodology for industrial product using HDI was developed in this study. Three lists of social impact factor were prepared (for each country) to implement SLCA.