About 800,000 tones of wastes have been piled up or buried illegally at prefectural boundary area between Aomori and Iwate prefectures. Over 200 drums that contained organic solvent were buried and the solvent leaked from the drums resulting into the pollution of soils and groundwater. Dichloromethane (DCM) is one of pollutants and its concentration in groundwater was over 100 ppm. We have studied whether indigenous bacteria in the groundwater in the polluted site degraded DCM under aerobic conditions. Gas-tight vials with 10 ml of groundwater samples and 5 ml of headspace were shaken at 25°C. After 15 days of shaking, DCM concentration in a sample decreased from 108 ppm to 25 ppm. The bacteria population was subcultured using DCM as substrate without other organic matters. The bacteria population degraded DCM, and chloride concentration increased, indicating that DCM was degraded biologically. The effects of pH and TCE were investigated on the biodegradation of DCM. The experimental results indicated that bioremediation by indigenous bacteria is promising way to remedy DCM contaminated soil and groundwater at the illegal waste dump site.
The explosion in water, a new crushing technique, is suitable in crushing and liberating hard materials such as the electric parts and waste construction materials. In this study, in order to evaluate the economical effectiveness of this method recycle system of composite materials of ceramics and metal recycle system as well as cellular phones recycling one were examined. Explosion of composite materials could reduce the landfilling area required for solid waste of insulator since well-separated ceramics could be reused, in contrary of ceramics-cement mix which couldn’t be used and remain as land fill solid waste. In explosion experiments on cellular phone, plastic-metal surface could be separated based on density difference between two materials. The cash-flow balances of these recycling processes were calculated. To minimize the process cost, it was suggested that a more effective explosion method and a relatively bid explosion pond are needed for the explosion. The payment balance of this system showed that the establishment of an efficient collection system, reduction in the transportation cost, was important. Investigation on the optimum cell phone recycling location based on shipping cost calculation found that Kanto, Tokai, Kinki and Kyusyu area are the optimum.