Electrochemical properties of leachate and the relationships between leachate properties and the resistivities of strata are studied in four landfill sites. Leachate contains large amounts of Na, K, Ca, Cl and HCO₃ ions. The solubility of Na, K and Cl ions is greater than Ca ion. Although the ion concentrations of HCO₃ are comparatively high, they are affected by the disposed materials and subsurface conditions of landfill sites. The conductivity of leachate is mostly controlled by the concentration of the above ions. Therefore, the conductivity decreases as the waste deposits are leached by natural replenishment. In addition, the resistivity of waste deposits is closely related to the conductivity of the leachate. On the other hand, most of the resistivity profiles reflect the structure and properties of waste deposits. The temporal changes in the resistivity of waste deposits would act as suitable indicators for clarifying changes in these conditions.

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This study is on the effective management by the quality control technique concerning the PCB detoxification plant.
The DMAIC Method (Define, Measure, Analyze, Improve, and Control) was applied to the actual construction permission procedure for the purpose of shortening of the construction permission period of a PCB detoxification plant. Firstly, the delay of Lead Time (LT), i.e., the duration period of the expert meetings is considered to be a defect in products, and a rate of defect (R%) was defined. Next, based on the failure mode effects analysis, Risk Priority Number (RPN) was calculated and the intensity of impact of the factors, which causes a defect, was evaluated. By execution of actions recommended in order to prevent the risk of the delay of LT, all RPN became less than 120 after the second expert meeting and the third expert meeting became the final meeting. Finally LT, which had required about ten months conventionally, was shortened to 4.5 months, and as a result, R=15% was obtained. Consequently, although quantification has been considered very difficult in the field of the construction management concerning a project until now, our study showed that this methodology is effective even in that field.

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For the recycling of waste rubber, the behavior of chlorine, sulfur and metals in solid residue during the thermal decomposition process of chlorinates synthetic rubbers with N₂ atomosphere at a maximum temperature of 800°C and a temperature rate of 5 K/min was investigated. The experimental results obtained by employing chloroprene (CR) and nitrile butadiene rubbers mixed with polyvinyl chloride (NBR/PVC) are summarized as follows :
1) More than 90 wt% of the chlorine contained in CR was converted to HCl gas, while about 60 wt% of sulfur remained in the solid residue. ZnCl₂ was formed by the chlorination of ZnO involved in CR during the thermal decomposition of the CR, and migrated from the solid residue by volatilization. As a result, no zinc was observed in the solid residue of CR.
2) Chlorine compounds generated from thermal decomposition of NBR/PVC were captured in the form of CaCl₂ by CaCO₃ filler, with a part of the CaCl₂ remaining in the solid residue. Most of the sulfur was converted to sulfurous gases, while CaS was found as a remainder in the solid residue.

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In order to use molten slag in environmental conservation we studied the removal and capture of lead ions in polluted water with crystallized molten slag.
Experiments were carried out on the reactions between crushed molten slag and lead acetate, lead nitrate and lead chloride solutions. Consequently, about 10 mg of lead per g of slag was removed and captured and it was confirmed that molten slag could be useful for capturing of lead ions. The mechanism for the removal of lead was more dependent on the precipitation reaction than adsorption. XRD and IR analyses revealed that basic lead carbonate (2PbCO₃⋅Pb (OH) ₂) was formed in the precipitations.
Basic lead carbonate was also formed by the reaction between the solution of the molten slag leachate and lead acetate, lead nitrate and lead chloride. Laurionite (PbCl (OH) ) was also formed by the reaction between the solution of the molten slag leachate and lead chloride. The hydrolysis of compounds that were formed by the reaction not only between the calcium hydroxide and lead acetate but also between lead nitrate and lead chloride gave basic lead carbonate and laurionite. These results agreed with the results of the experiments above. Calcium oxide in the molten slag was concluded to be an important factor in removing and capturing the lead ions.

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The purpose of this study is to develop a seasonal fluctuation model using information from a time series analysis on the collection amount of municipal solid waste. In this study, we make an analysis of seasonal fluctuation to show the relationship between the irregular component in a time series and the scale of waste collection amount.
Firstly, we defined the cyclical, seasonal, and irregular components in a time series, and developed a seasonal fluctuation model with a finite Fourier series. Secondly, we examined the data size required for an application of the model to consider the effect of temporal changes on the components of the model. It was shown that the model application required a period of more than five years for an adequate data size. The abstraction of the seasonal component was then not affected by the data period. Thirdly, in order to determine the quantitative characteristics of the component composition, we used the contributory ratio ρ_k that is calculated from the square of the amplitude X_k.
Lastly, we applied the model to data on household and commercial waste in several cities. It was found that the irregular component propotion decreases as the amount of the waste collection increases.

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The purpose of this study is to examine what aspects of children's environmental cognition and behavior are influenced by social factors relating to their parents? Two hundred and seventy six pairs of 4th to 6th grade children and their caregivers (or parents) were surveyed in two elementary schools through questionnaires. The major findings were as follows. Parent-child conversations had only a weak effect on arousing children's environmental conciousness. Praising or advising by parents had a little effect on facilitating children's waste reduction behavior. Parents' waste reduction behavior had a great influence on children's behavior. The results indicate that children acquire waste reduction behavior by imitating parents' behavior in order to meet parents' expectation.

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