“The Law for Promotion of Sorting and Recycling of Containers and Packaging”is expected to be the most effective solution for the solid waste problem. But, it brings with it a large financial burden for local governments. In this paper, the authors try to make quantitative evaluation of the effects of separate collection of resource waste on the reduction of solid waste.
The increase of resource collection rates and decrease of intermediate treatment amounts are expected as a result of the introduction of separate collection of resource waste.
On the other hand, we have some fear that the decrease of calorific value and increase of financial burdens may occur.

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The effect of leaching conditions (S/L and pH) on the toxicity of municipal waste incinerator fly ash leachate was evaluated with an algal toxicity test.
The leachate prepared with pH=7 and S/L= 10w/v% was 5 times more toxic than that prepared with same pH and S/L= 1w/v%. But the latter released twice as much toxicity per fly ash than the former. The major toxic constituents in both of the leachates, however, were the same, i.e., zinc. 61% and 44% of the toxicity were estimated to be due to zinc for the leachate prepared with S/L= 10 w/v% and 1w/v%, respectively.
The toxicity of leaches prepared with the same S/L ratio (1w/v%) and varied pH levels 4, 7 and 12 was also compared. Among these three leachates, the leachate of pH=4 was most toxic. Its major toxic constituent was also zinc, causing 44% of its toxicity. Lead, on the other hand, was expected as the major toxic constituent of the leachate prepared with pH=12.
This implied that zinc and lead must be specifically targeted in MWI fly ash treatment and disposal.

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In recent years, increasing waste has led to a shortage of space for land disposal site.Therefore, sea area final disposal at sea has become the predominant method.
In this study, we propose a method of evaluation and site location with public participation for selecting alternatives of sea area disposal sites and related transfer stations.
Firstly, we make it possible to evaluate the alternatives from various view points by public participants. Therefore, we introduce the λ-fuzzy measure method, which is composed of λ-fuzzy measure and a fuzzy integral as the method calculating total evaluation points of alternatives. This method can evaluate an alternative with positive features with a high score or without weak points, considering the assessments from various public viewpoints. We apply the AHP method for calculating the weight and evaluation point for each evaluation factor.
Secondly, we apply our method for the practical problems of site location, and show that this method is applicable to evaluate and select alternatives.

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The service life expectancy of municipal solid waste incinerators (MSWIs) was estimated from both maintenance condition data of 87 MSWIs researched from 1994 to 1996, and from 1995 surveys on the decommissioning of MSWIs. First of all, in order to determine a mathematical model for the service life expectancy of MSWIs, normal distribution, logarithmic normal distribution and Weibull distribution were applied to the data from decommissioning MSWIs. Among these models, the compliance of Weibull distribution to the data was best. MSWIs had an average service life expectancy of 15.7 years, according to the decommissioning data, and 16.4 years when considering connection between each equipment from repair frequency data, applying Weibull distribution. By assuming that the ratio of maintenance costs to facility construction costs can be applied to Weibull distribution, service life expectancies were computed. The average service life expectancy of MSWIs with continuous stoker (boiler) was ranged from 18.2 to 37.4 years. The shape parameter in Weibull distribution indicates that MSWIs overall tended slightly to wear-out failure.

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In an attempt to check the stability of insolubility of hazardous heavy metal elution characteristics from the landfilled fly ash immobilized by chemicals, the authors of this paper have studied the stability of immobilized fly ash for a period of about two years, using large-sized landfill lysimeters of the anaerobic landfill type, filled with fly ash immobilized by chemicals as well as bottom ash and non-combustible shredded solid waste.
The results of the study have revealed that the mass of the Pb and Cd stemming from leachate is smaller by far than the total mass of Pb and Cd contained in the solid waste. Furthermore, the elution tests of the fly ash immobilized by chemicals have demonstrated that the immobilized fly ash trapped hazardous heavy metals in a stable manner. Elution of hazardous heavy metal from solid waste greatly depends on the pH value of the seepage leachate in the solid waste layer. The change of the leachate quality over time is greatly affected by rainfall. A conspicuous change in water quality was observed particularly at the time of strong rainfall and in the event of much precipitation. The pH value of the leachate remaining at the bottom of the lysimeter was observed to decrease and the concentration of hazardous heavy metals in leachate from the lysimeter tended to be higher than that of seepage leachate.

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To obtain basic data for the prevention of littering, a public space in the Hiroshima University campus, “Spain Square Steps”was set up as an experimental field and its adaptability was discussed. Dividing a week -including rainy days- into 20 parts, the composition of the litter was analyzed. Using an interval camera, the sources of the litter -passersby and people at rest- were also recorded.
Since only passersby were observed littering on a rainy day, it was suggested that the unit of scattered wastes per man-hour be calculated by using the number of people at rest for bottles & cans, and by the total number of people for cigarette butts. The units for bottles & cans and cigarette butts were 0-0.16 (0.10 for a weekly average) and 0.54-1.0 (0.66) (number/man-hour), respectively.
The setting up of the experimental field was considered to be adaptable. This experimental field can be put to practical use for the study of prevention of littering. Using the amount of litter under usual circumstances as reference, changes in littering may be sought after establishing legal regulations, setting out garbage receptacles, and/or carrying out education activities.

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