In this research, we considered the roles of life cycle assessment (LCA), the limits of LCA, and countermeasures for the limits of LCA in reconstruction of the urban infrastructure. Concretely, LCA of 15 cases using a combination of technology and facilities was carried out for assessment of the urban waste and wastewater treatment system for comparative assessment. Life cycle simulation was done based on LCA results for 2050 to compare the measures scenario with the BaU (business as usual) case. In addition, analytic hierarchy process (AHP) was examined as a tool for integrating criteria evaluation for multi-objective decision-making, and the sensitivity analysis was attempted. Finally, to analyze the influence which the urban infrastructure gave to the material flow of the urban area, the analysis example was shown about the material flow cost accounting on an urban scale as effective cooperation of LCA and material flow analysis (MFA) and systematic expressions.
It is necessary to select material cycle system with less environmental burdens for establishment of sound material-cycle society. Regional material cycle is often desirable in term of transport and price of recycled products. However, Supply and demand of recycled product in certain region are not always balanced, so the surplus must be disposed as usual. It has not been considered sufficiently in the existing studies applying Life Cycle Assessment (LCA) to material cycle system. Influence of supply-demand balance of recycled products on comparative results of environmental burdens with material cycle systems was considered and formulated in this study. As a result, it was found that only the technological factors dominate the comparative results of the environmental burdens with the systems when both the possible supplies of recycled products are less than their demands. The demands become the factor when both of the supplies are more than them. The waste generation also becomes the factor when only the one side of the supply is more than the demand. As a case study, regional material cycle systems including garbage composting or biogasification in City A were assumed. Greenhouse gas emission with them was compared by application of LCA, and impacts of waste generation and product demand on the results were considered. As a result, compost demand influenced on difference of GHG emission among the systems stronger than liquid fertilizer demand. As a conclusion, supply-demand balance must be considered to exactly compare the environmental burdens with regional material cycle systems.
An objective of this study is recycle-flow analysis on used cellular phone based on total materials requirement (TMR) as a case study of recycle-flow analysis which reflects quality of resources. This paper consists of following contents: a) estimation of recycle-flow, b) quantitative analysis of cellular phone composition based on experimental observations, and c) analysis on recycle-flow based on TMR. Above-mentioned estimation and analysis gave us the following results. 1) A recovery ratio of used cellular phone is estimated as 31%. 2) Used cellular phone mainly consists of Au (41%), Cu (23%), Pd (19%) and Pt (7%) based on TMR, while main composition (weight base) of that is plastics (69%), Cu (11%), glass (8%) and Fe (6%). 3) Material recovery-ratio (weight base) in recycle process is 11%, and that (TMR base) is 90%. 4) Material recovery ratio (TMR base) in recycle system, which is taken the recovery ratio into consideration, is only 28%.
Various eco-services have been recently introduced in Japan as a proactive approach to create a sustainable society. These eco-services include a wide range of businesses and each eco-service has its own unique characteristics. It is necessary to systematically classify these eco-services into different categories to understand the development trend as well as to promote these eco-services with regard to sustainable development. In addition, overall environmental impacts and economic benefits of these eco-services need to be quantitatively evaluated using a life cycle approach to ensure the real benefits of eco-service business. Two different scenarios for a municipal waste treatment system by comparing landfill and recycling in cement production were used as a case study. The overall environmental impacts of these scenarios were quantitatively evaluated in this research by using a life cycle impact assessment (LCIA) method known as “LIME”. Study results indicated that the use of municipal wastes in cement production could reduce overall life cycle impacts
In this report, results of life cycle inventory analysis are described for evaluating the environmental impact in food production processes including beer production and tofu production in terms of the cumulative CO2 emission unit. It may be considered that the food production is a process where biomass raw materials are converted into food products which are further packaged in suitable sizes for transportation and sale, by supplying utilities such as electricity, water, fuel, package materials etc. It should be noted that biomass wastes themselves are endowed with carbon-neutral nature and the conversion of food wastes does not leads to any artificial increase of CO2 in the environment except for that due to utility inputs. In order to minimize the environmental impacts from the overall production processes, it is necessary to evaluate the cumulative CO2 emission unit or amount of CO2 emission for every unit processes included in the whole production process and to find the possibility of reducing the CO2 emission for some specific process unit from which a particularly large emission fraction to the whole emission would occur, by selecting an alternative production scheme. Also it may be pointed out that in a food production there are many processes where the material is heated or cooled being accompanied by a large amount of heat input or heat discharge and, therefore, adoption of efficient method(s) for saving energies is important. Furthermore, in the food industries, large amounts of organic solid wastes and wastewater rich in organic dissolved substances are discharged. It is the key issue for decreasing environmental impact from the net food production process how to choose an energy-saving method for treating these wastes. In addition, it is important to exempt from discharging any secondary wastes by producing usable products from the raw food wastes and sub-products. Note that it is an effective way to evaluate the amounts of various wastes in either solid or liquid state on a common elemental-carbon basis. Thus in the present research we evaluate the effect of methane fermentation of solid wastes together with or without liquid waste on the net environmental impact in terms of the cumulative CO2 emission unit by comparing alternative waste treating methods including, incineration, drying, composting and others. It may be important to adopt the most effective way to reduce the environmental impact in treating the food wastes. We should know about two issues regulating the food wastes emission: “Law of Food Waste Recycling” (2001) and “Biomass Nippon Total Strategy” (2002). In these issues, recycling methods for the food wastes are classified into the three methods: (1) utilization as raw materials for fertilizer and feeds, (2) renewal use of food waste as feed, fertilizer, oil, plastics, methane etc., (3) reduction of food wastes including dewatering, drying, fermentation, carbonization etc. The effective utilization of food waste is expected to restrain the global warming, to contribute in leading to the resource-recycling society, to grow the strategic biomass industries and to activate the local economy for agriculture, forestry and fisheries. It should be pointed out that important thing is to minimize the environmental impact on the basis of a LC-CO2 inventory analysis by selecting the best promising way among alternative processes.
Nowadays, since plastics are used throughout our societies, the issues surrounding plastic wastes have become a typical and symbolic part of the discussion on waste treatment and recycling. Recycling of plastic wastes is classified into four methods such as reuse, material recycling, chemical recycling and thermal recycling (thermal recovery). The LCA is applied to the estimate of these recycling methods for the reproduction of PET resin. In comparison with the production of PET resin by chemical recycling and thermal recycling, the material recycling can reduce the environmental loading such as energy consumption and pollution. However, the quality of recycled PET and impurity in plastic wastes cannot be estimated by LCA. In comparison with the production of virgin PET resin from crude oil, the monomer recycling process can reduce the environmental loading such as energy consumption and pollution so that it seems to be usable as a practical method for the recycling of PET from bottle to bottle. The importance of appropriately combining sorted waste collections and recycling technologies is pointed out.
The environmental impacts and life cycle costs (LCC) of garbage utilization systems were estimated by LCA procedure. Five types of garbage utilization processes were considered: composting; methane fermentation + effluent disposal, methane fermentation + liquid fertilizer, gasification melting and stoker-type incineration. An inventory analysis was carried out to evaluate the environmental loads of each system for construction, processing, and transportation. The environmental impacts were estimated using LIME (Life Cycle Impact Assessment Method based on Endpoint Modeling). The effects of substitution for chemical fertilizer and electric power generation were taken into account in the environmental impact analyses. At the same time, the life cycle cost of each system was calculated using the same functional unit and system boundaries as set in the LCA. Results indicated that the stoker-type incineration system would have the largest environmental impact among the garbage utilization systems considered. The methane fermentation system was more effective in reducing environmental impacts if effluents were used as liquid fertilizer. The effect from saving resource by using liquid fertilizer from the methane fermentation process was significantly large. On the other hand, effects from the electric power generation from incineration or gasification melting systems were negligible. From the point of life cycle costs, construction and collection costs were dominant in all the considered systems. The gasification melting system was estimated to be the most expensive due to its high construction cost. The methane fermentation system was concluded to be the most effective means of garbage utilization for both environmental impacts and life cycle costs.
Energy and environmental loads on four types of batteries of lead-acid (PbA), nickel-cadmium (NiCd), nickel-metal-hydride (NiMH) and lithium-ion (Li-ion) batteries were analyzed for high-efficiency usage of electricity using a life cycle assessment method. The net total efficiency was estimated considering loads on the material process such as production, manufacturing and use. This total efficiency was calculated with the ratio of the life cycle discharged energy to the life cycle input energy. The CO2 emission intensity was also analyzed for the electric-load leveling. In case of using the nighttime electricity, the CO2 emission intensity for the battery system decreased to almost the same level for the CO2 intensity of the daytime electricity. In particular, the lithium-ion battery showed the smallest loads. The effects of use conditions for the battery such as the depth of discharge (DOD) and the discharge rate (C rate) were then analyzed. It was clarified that the CO2 emission intensity was varied according to the use condition.
A simulator assessing the environmental impacts of agricultural activities in Miyako-Island was developed. The input data are cultivated acreage of each crop and the number of cows. The outputs are 1) inventories of environmental loads such as CO2, CH4, N2O, NOx, SOx, NH3 and NO3−, 2) the environmental impacts at midpoint such as global warming potential, acidification potential, effect on groundwater and energy consumption and 3) the environmental impacts calculated according to the LIME method at midpoint. The features of this simulator are 1) it enable its users to estimate the environmental impacts with a small number of input data since default data based on the present conditions of agricultural activities in Miyako-Island are included in the simulator, 2) it also allows its user to input their actual data in place of the default ones for more precision and 3) it gives the information about the environmental impacts by changing the amounts of synthetic fertilizers applied and the crop yields. The environmental impacts by a typical farmer’s activities in Miyako-Island were estimated with this simulator and the results are following: 1) a significant fraction of CO2 emissions was originated from concentrated feed, chemical fertilizer, diesel for agricultural machinery and waste plastics and 2) Global warming potential was estimated as 44.1 t-CO2eq/y and main contributors were CH4 from rumination of cattle and N2O from manure treatment. Moreover five different scenarios on chemical fertilizer usage and cattle breeding were used for simulations and the results were discussed in the paper.