To increase the recyclability of home appliances, it is important to disassemble the parts that can be recycled and those that consist of hazardous materials at the early stage of disassembly. It is therefore important to design a product that can be disassembled easily. This study shows the possibility of the development of environmental or “green” products through the analysis of the assembly and the disassembly of an automatic washing machine. This analysis can reduce a complicated structure to a simple one and also leads to simpler manufacturing processes. The analysis and improvement of the financial consequences of disassembly can maximize profit at the end of a product's life, and allows a determination of when to stop disassembly.

View full abstract

Composition of input waste at a RDF production facility is the predominant factor for determining the configuration of processes, and the characteristics of the produced RDF. The authors modeled the following source separation scenarios: 1) combustible MSW, 2) combustible MSW without food waste to reduce energy consumption, and 3) combustible MSW without plastics to reduce hydrogen chloride gas generation during combustion.
Food waste inclusion has the advantage of a lower MSW disposal cost, but lowers energy production. Plastics exclusion is highly disadvantageous both in terms of cost and energy performance, especially when the RDF production facility is small in size. Because HCl gas can be reduced by other technologies or equipment, using combustible waste without removing food waste and plastics is the best choice as raw material for RDF production.

View full abstract

Polychlorinated biphenyls (PCBs) were found to cause a liver disorder, so their production and use was banned and the possession of them becoming obsolete is now mandatory. However, the result of holding such equipment over a long period of time was that containers became more and more time worn with an increased danger of PCB leakage. These are reasons why prompt establishment of a technique that can detoxify PCBs is desired.
The Base Catalyzed Decomposition (BCD) process is based on the formation of hydrogen radicals through a liquid phase dehydrogenation reaction. Hydrogen radicals generated from hydrogen donor substitute chlorine atoms of PCBs and PCBs become non-toxic biphenyl.
To establish the BCD process, this report examines the rate-limiting factors that are considered to influence reaction rate. This was done to obtain findings for determining the optimum reaction conditions, as well as examine the reaction products to ascertain the complete dechlorination. The dechlorination reaction by BCD process could be assumed as a first-order reaction and the activated energy was obtained. It was confirmed that the amount of sodium hydroxide being added has an influence on the reaction rate.
One hundred percent dechlorination was confirmed by a quantitative analysis of inorganic chlorine as a reaction product.

View full abstract

With increasing amounts of municipal solid waste treated by incineration, there is an increasing potential for environmental pollution by heavy metals from incinerator ash. The research team previously investigated and published on the fundamental condition (Temperature, pH, ORP, TOC) of biological sulfate reduction in incinerator ash leachate. In this paper, ash from 8 incinerators was studied to determine the influence of ash characteristics on sulfate reduction in ash leachate neutralized by CO₂injection. Also, influence of the inoculum source was studied.
Consequently, the following conclusions were obtained.
1) Considerable sulfate reduction occurred when the TOC in ash leachate was higher than 200 mg/L.
2) When highly active inoculum was used, a quick and large sulfate reduction occurred.
3) The main process of sulfate reduction was incomplete lactate oxidation.

View full abstract

The citizens of Gotemba city were asked whether they approved or disapproved of introducing a monetary charge policy for supermarket bags. Results showed that 78.1% approved of the policy. More over when we asked what would happen if a 5 yen charge were introduced, 16.9% answered that they would bring their own shopping bags. In the case of a 10 yen charge, 44.2% would bring their own. In the follow-up investigation into actual conditions, we found that 73.2% did indeed bring their own bags at the 5 yen charge policy, and 91.8% brought bags at the 10 yen rate. These results provided an interesting comparison of investigation by the questionnaire by CVM and the actual conditions. The difference between these at the 5 yen rate was 56.3% and at the 10 yen was 47.6%. That is to say, there is a “Hypothetical Bias” and the difference between an open-ended question and a closed-ended question was mainly observed with the CVM questionnaire answer being 50-60% less than actually observed.

View full abstract

The sampling and analysis method is proposed for the measurement of chlorobenzenes and chlorophenols in emission gas of a municipal solid waste incinerator, based on results of recovery tests. The sampling method was evaluated by varying the sampling gas temperature and flow rate. According to the results of recovery tests, the lower temperature of sampling gas attained a higher absorption efficiency of diethylene glycol, and the low flow rate of sampling gas was beneficial to the activated carbon chip trap. In the analysis of sampled gas, the clean-up method was elaborated based on standard compounds. The amount of loss for each standard compound during clean-up procedure was less than 20%. Finally, two types of gas, one from the upper part of the fluidized bed and the other taken from the outlet of the secondary combustion chamber, were sampled and analyzed by the method proposed in this paper.

View full abstract