In order to support effective patrolling for illegal dumping, we analyzed possible related geographic attributes and their probabilities of illegal dumping using Geographic Information System (GIS) data. We collected data on 608 illegal dumping sites at the regional level in units of municipality, as well as data on 421 sites at the site level in units of 25 -m mesh. We then calculated the relative probabilities of illegal dumping for 31 geographic attributes which may affect illegal dumping, and hence clarified which sites are likely to be frequently used for illegal dumping. Finally, from among the geographic attributes we identified the main ones which would be related to illegal dumping, based on the results of correlation analysis, factor analysis, and explanatory adequacy. There were seven main geographic attributes: population density, income per capita, unemployment rate, topographic features, distance from roads, distance from main roads, and depth from forest edge.

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Behaviors and properties of permeable water in waste deposits were studied at a controlled landfill site. Three observation wells of different depths were installed in the site. The depth of the screen ranged from 1 to 4 m in the shallow well, 4 to 7 m in the middle well and 7 to 10m in the deep well. Temporal changes of the water-table level and the quality of the water were examined for each well throughout the year. In addition, electrical prospecting was carried out in the site to clarify the structure of waste deposits. These results show that the waste deposits consist of permeable and impermeable zones. This implies that the behaviors of the water in the deposits should be clarified with respect to interpreting the stabilization of the deposits by the temporal changes of the quality in leachate.

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In order to recover abrasive grains from waste grinding wheels (phenolic resin and abrasive grains), combustion/thermal degradation of waste grinding wheels was carried out in both an O₂/Ns₂ (20/80%) atmosphere and a steam/N₂ atmosphere at 800°C in a batch reactor. In the present study, two kinds of grinding wheels were used : sample A consisted of Al₂O₃/SiC/Phenolic resin (70/20/10 wt%), and sample B consisted of Al₂O₃/Phenolic resin/FeS₂/K₂SO₄/KCl/CaO/Glass fiber (53/7/25/7/2/2wt%) .
Through combustion at oxygen ratios of 1.1-2.6, carbons of the phenolic resin in both samples A and B were converted almost completely to CO₂ in 5-20 minutes. It was confirmed that the main abrasive grain component, Al₂O₃, could be recovered from the solid residues. In addition to CO₂ generation, gases such as CO, lower-hydrocarbons, and NOx were detected during the thermal degradation of sample A in an O₂/N₂ atmosphere. In the thermal degradation of sample B, SO₂ and HCl were detected among gases such as CO₂ and CO. Behaviors of CO₂ and CO formation were observed in the thermal degradation of sample B in the stream/N₂ atmosphere similar to those in the thermal degradation in the O₂/N₂ atmosphere. In this case, lower-hydrocarbons, CS₂ and H₂S were detected along with CO₂ and CO. However, the main abrasive grain, A1₂O₃, was found to be recoverable through thermal treatment in the steam/N₂ atmosphere.

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Composting is low cost and environmentally friendly, making this practice an important component of integrated and sustainable waste management systems. Properly aged compost that is sanitized and stabilized can benefit plant growth and the environment, but immature composts can impair plant growth and degrade the quality of the soil. Because of the wide variety of organic wastes, a standard reliable quantitative method has not been developed to evaluate compost quality. This is one reason that recycling of organic wastes has not become more widespread. Therefore, a test is needed to monitor the degree of decomposition of heterogeneous organic materials, including food products, animal manures, and plant residues.
A bioassay test with hypha (Pleurotus ostreatus) was developed as a method of compost quality evaluation to solve this problem. This method measures the growth speed of hypha on culture mediums containing compost after different numbers of days of fermentation, and the quality of compost is evaluated by the difference of the growth speed of hypha. The results were compared with other tests such as the germination index and the analyzed growth inhibitor. This research suggests that the compost quality evaluation bioassay test using hypha growth response is more sensitive than the other tests are.

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Cement soil stabilizers (CSSs) are usually used for foundation improvement works. Environmental controls should be taken into account. Leachate control of Cr (VI) is the largest concern, because CSSs contain Cr (VI) at concentrations of around 10 mg/kg. This content is suspected to be that Cr (VI) releasing from stabilized soil by CSS exceeding the environmental criterion of 0.05 mg/L in leachate. Control of Cr (VI) by design of combinations may offer the best solution, but few studies have been reported. A series of lab tests were carried out for confirming the potential for depressing Cr (VI) concentration of leachate. The conditions of soil CSS combinations and drying methods of leaching pre-treatment were changed and leaching characteristics were examined. The results are as follows. Correlation is low between unconfined compressive strength and Cr (VI) in leachate. The difference in the soil types influences leaching characteristics, in particular, Loam stabilized by ordinary CSS is difficult to keep within the environmental criterion. Cr (VI) in leachate is increased by being dried or oxidized at pre-treatment. In this paper, there is good correlation between the Cr (VI) in leachate dried by 40°C oven dried and the leachate which is atmosphere dried (standard method), and confirming the potential for shortening the time needed for the measurement from about 10 days to 2 days. The stabilizer with reducing agent depresses Cr (VI) in leachate.

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Static corrosion tests were performed for SiO₂-CaO-Al₂O₃ slag specimens in aqueous solutions ranging from acidic to alkaline at 40°C to observe the effects of the solution pH and slag basicity on the dissolution rates of the slag. The initial dissolution rates of the slag were investigated, and were obtained with little disturbance caused by the change of the leachant properties such as elemental concentrations or pH. The initial dissolution rates were evaluated by normalized elemental mass loss per day. It was found that the initial dissolution rates of the slag in acidic and alkaline leachants were higher than those in near neutral leachants. The basicity of the slag did not affect the initial dissolution rates of the slag in the alkaline solutions. The initial dissolution rates in acidic solutions increased in proportion to the basicity of the slag, which is probably a result of the dissolution properties of the network structure of the slag.

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In Japan, under a law for the recycling of specified home electrical appliances that came into effect in April 2001, the recycling of plastics from recovered home appliance waste (i.e. televisions (TVs), refrigerators, air conditioners, washing machines) has become a very important issue. Specifically, it is difficult to recycle the plastics found in TVs due to the flame retardant compound in these. The first part of this paper investigates the types of plastic, weight, contents and level of the flame retardant for the back cabinets recovered from waste TVs (TV-BC) . These investigations made it clear that the TV-BC are made of flame retardant polystyrene. Many TV-BC which were recovered from waste TVs at a recycling factory for home electrical appliances were then studied. In this study, we found that the recovered TV-BC had good stability of properties such as specific gravity, melt flow and IZOD and that the recovered TV-BC showed good capability for material recycling.

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