A word "stock-based society" has been proposed as a society opposite to a "flow-based society" characterized by mass production, consumption, and disposal. This paper discusses future development of system analyses toward stock-based society from the viewpoint of waste management in particular, and points out the followings: 1) Importance of understanding material stocks that are considered to increase in the economic society and their evaluation as potential wastes and resources in the future; 2) Importance of including stock accounting in macro and micro environmental accounting system; 3) Importance of assessing long-term use of existing stocks in more expanded system boundary and developing indicators related to stock-based society.
The aim of this research was to characterize the material flow of spent automobile lead-acid batteries in Japan. Questionnaire survey was performed to analyze the consumer behaviors about exchange and dead storage of batteries; interviews to local authorities were conducted to reveal the actual status of battery collection by the municipal governments; trade statistics were analyzed to estimate the amount of batteries exported as second hand products. Return rate of batteries was over 90% at gas stations and about 60% at DIY shop. The local governments collected about 1-10% of spent batteries. The second hand battery export increased from <0.1 million in FY 2003 to 4.8 million in FY2005.
The biomass available in Kyoto City was estimated to be 2.02 Mt-wet/yr of which waste paper, waste timber from construction etc., food waste, unused forest and sewage sludge account for the largest amounts on an energy basis. Based on Kyoto's regionally specific biomass potential and its historical use of biomass, we started "Kyoto-Bio-Cycle Project" in 2007. This project was carried out in order to synergistically enhance the effect of greenhouse gas (GHG) countermeasures, through greening of necessary materials and the cyclic use of byproducts, with "Kyoto City's project for the manufacture of biodiesel fuel from used cooking oil" as the core activity. This project consists of 5 technological development topics "Gasification and methanol synthesis, BDF resource material expansion, High efficiency biogasification, Application of biogas to Fuel Cell, Life-cycle system analysis", utilizing the forestal biomass in addition to the so-called urban waste biomass. In 2007, we constructed demonstration plants and developed elemental technologies. From our estimation, by collecting and recycling plastic packaging waste and introducing these new technologies in Kyoto City, GHG emissions would be reduced by 60 % as compared to the current method of incinerating waste wood, cooking oil and other combustibles.
Japanese government surveys the state of discharge and treatment of municipal solid waste every year. For the last two years, the survey was twice revised to obtain useful information. This presentation introduces the major revisions and explain the basic ideas for the revision, as well as future direction of the survey.
For making a study on control of cadmium, life cycle flow in Japan and relation with other countries about NiCd batteries including cadmium were analyzed. As a result, it was appeared that within the country, the collection and recycling systems of NiCd batteries did not function and the amount of exported cadmium as metal is increasing while the amount of production is decreasing.
Additionally, it was indicated that mineral ore such as zinc ore including cadmium, cadmium itself and productions including cadmium were dynamically distributed in Pacific rim.
It was concluded that the discussion about control of cadmium on a global scale was necessary.
Processed sandy residue, which was going to be landfilled, generated from mixed construction and demolition waste was selected as the subject of the study, and understanding basic property and discussion of composition of ignition loss (IL) were conducted. From the above, the target material for decreasing IL was elucidated, and then validity of IL used in landfill standard for inert industrial solid waste was discussed. (1) The mean values of IL were mostly above 5 % and the residue should not be dumped in inert type landfill in principle. (2) From the results of heavy medium separation, wood is about 2 % and plastic is below 0.1 % for the floating material, and about 8 to 13 % is the amount of organic matter (0.45 % as paper) and combined water for sediment. The amount of these values was estimated as IL of the residue. (3) Most of IL in the sediment was possibly due to dewater of combined water contained in mortar. From the above, since most of IL of sandy residue was due to combined water, IL could not be decreased to below 5 % even if wood, which is major organic matter in sandy residue, was removed.
Material stocks in economic society are considered to represent a reserve for future wastes and secondary resources. In this paper, we defined materials that have a high probability of emerging as wastes in the future as potential wastes and estimated that amount for construction minerals in Japan. We also identified the types of materials that have a low probability of emerging as wastes, i.e., non-potential wastes, and estimated that amount as well. The following conclusions were drawn. 1) We classified construction minerals input into economic society as potential wastes, potential dissipated materials, dissipatively used materials, and permanent structures. 2) The proportion of potential wastes was estimated to be about 30% of the total construction minerals that have been input into and accumulated in Japanese economic society. 3) Introduction of the concept of potential and non-potential wastes provides a more accurate assessment of the waste that will emerge in the future and environmental impacts and resource losses that non-potential wastes might generate.
Material flow and stock accounting of commodities is important for planning and implementation of recycling and appropriate waste treatment or utilization of stock in society. Information of life span distribution of commodities is indispensable for such estimation and some dozen of research and survey on life span distribution have been reported. However, the definition and the type of the distribution vary by research or survey, therefore, the data might be utilized for estimation in inappropriate way. In this context, the authors organized the definition, type and estimation methodology of life span distribution of commodities and discussed the pros and cons of each of them from the viewpoint of utilization for flow and stock accounting. Then, the authors reviewed existing data of life span distribution and compiled them in a database.
Action research concerning refusal of plastic bag was conducted at the supermarkets. The results showed that actions, such as salesclerk asking customers abut the needs of plastic bag, had effect 5% reduction of refusal rate.
Reduction of carry bags made from high-density polyethylene (HDPE) is significant for recycling-oriented society formation.
One of the methods for the reduction of polyethylene bags is to pay fee for polyethylene bags. Therefore, it is important to clarify the reason of the citizen who is opposed to pay.
In this paper, the purpose of this research is to clarify the prevention factor over charging polyethylene carry bags, by the questionnaire to user of retail distributors.
The results is shown as followings.
(1) Presently, about 30 % of users agree and 30 % of users do not agree.
(2) The main reason of polyethylene carry bags is to reuse for disposing garbage.
A future subject is clarifying opposed reasons of user in detail in order to promote the charging polyethylene carry bags.
We clarified the validity of changing of resident consciousness and action by age groups to go with innovating charge for waste collection in Fukuoka city. Results from this study were as follows;
1) The introduction of charge for waste collection has a positive effect on waste reduction for young or middle generation (from 30 to 49 years old) and middle generation (from 50 to 64 years old),
2) But it has no advantage for young generation (from 15 to29 years old) and senior generation (more than 65 years old), although large-sized cities have high percentages of such generation,
3) It is important for young generation (from 15 to 29 years old) to improve resource recovery system or PR activity, and it is also important for senior generation (more than 65 years old) to reduce the time-consuming load for waste recycling by increasing recycle box or door-to-door collection.
Akashi city in Japan is tackling in solid waste reduction and recycling with having long-term goal towards realizing a sound society of material recycling, therefore the number of group recovery activities and the amount of recovered MSW are now increasing. If the solid waste recycling by community is encouraged by the local government is the more increase of recycling ratio may be expected. In this study, we aimed to identify the factors which influence on the recycling activity through modeling the amount of group recovery by expressing social and regional factors. Concretely, data of group recovery and related factors are collected, GIS map of the region, group, and stores are created, and after that, modeling of the amount of group recovery was concluded. In analysis, association of the age factor, the status of household, and the number of cooperative volunteer are considered.
To achieve citizens' behavior modification on 3R, the authors provided information to the residents in selected areas of Tsuyama city. Questionnaire surveys and waste composition analyses were conducted to estimate the effects before and after the PR activities. The focuses of PR activities were recycling of paper packaging/ containers, kitchen waste disposal at-home, and waste reduction such as bringing own bags. The authors held explanatory meetings for the target residents, and distributed leaflets and durable bags to the residents who didn't participated in the meetings. The results indicated that the participation rates for these 3R behaviors were improved and the PR effects on the participants of explanatory meetings were the largest. Regarding unit waste discharge, paper packaging/ containers was decreased to 17.3g/person/day after the PR activities compared to 20.8g/person/day before the PR activities.
A questionnaire survey on recycled products qualification program organized by prefectural governments in Japan and follow-up studies based on the official websites of each program were conducted to gain an understanding of the actual situation.
Our results show that, of 47 prefectural governments in Japan, 35 have implemented the program, and 4,000+ products have already been qualified. Of all, four types of qualified products, namely precast concrete, crushed rock, paving and asphalt, accounted for the half of total numbers.
The questionnaire survey revealed that a total of 4.2 million ton of qualified products has been sold, and about 13 billion yen has been spent for procuring a total of 5.5 million ton of products. The amount of recyclable resources used in qualified products was estimated as >12 million ton/year in the 35 prefectures surveyed.
A number of impoverished people in developing countries engage as waste pickers who are scavenging recyclables from disposed solid waste along urban streets and in open-dumping waste disposal sites. Such waste pickers are taking a role of 3R (Reduce, Reuse and Recycle) practice in developing countries, where proper recognition of the waste pickers' activities is indispensable for effective solid waste management. In this presentation, the results of problem analysis for solid waste management in Buenos Aires is summarized in order to identify the needs and intention of waste pickers, and introduced an attempt of institutionalization of waste pickers' activities into the municipal solid waste management in Buenos Aires city. Based on these facts, appropriate municipal solid waste management system for developing countries is studied.