In this study, we determined the amount of metal in one desktop personal computer (PC) as a case study of electronic and electrical waste (e-waste). Using a three-step process, we dismantled the PC. We then analyzed the metal content of each part. The circuit boards contained 0.794g of Ag, 0.143g of Au, 0.186g of Pd, 91g of Al, 187g of Cu, and 17.8g of Pb. In total, the PC contained 0.79g of Ag, 0.143g of Au, 0.19g of Pd, 420g of Al, 320g of Cu, 7200g of Fe, 77g of Zn, 23g of Nd, and 20g of Pb. We also evaluated the maximum recoverable amount of metal (M-max) from waste PCs in Japan per year and determined that the M-max for Au, Ag and Pd are 1.1, 5.9, and 1.4 t per year, respectively.

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The depletion of mineral phosphate as a resource is of great concern. Seeing as incinerated sewage sludge ash contains the same level of phosphorus as that of mineral phosphate, there is a possibility the ash can actually be used as a substitute. This research is aimed at clarifying the composition range of incinerated ash from sewage sludge, whereby slag fertilizer of the appropriate quality is obtained using a melting process. In addition, the safe application of the generated slag fertilizer on agricultural fields is also examined.
To examine how the quality of slag fertilizer will be influenced by differences in ash composition, it was produced out of model ash. Findings showed that the slag fertilizer satisfied quality standards when the ash is composed of : 17wt% or more phosphoric acid, 15wt% or more magnesia oxide, and 40wt% or more alkali. It was also confirmed that slag fertilizer of the appropriate quality can be produced from incinerated ash at disposal stations, as long as the ash composition can be adjusted to satisfy the above-mentioned values.
After the safety of heavy metals found in the slag fertilizer was examined through a content test, it was confirmed that the lead and chrome amounts satisfy values regulated by the Fertilizer Control Order. Upon analysis of crops where the slag fertilizer was applied, it was determined that lead, cadmium, and chrome amounts are below the accepted maximum limits stated in the Food Sanitation Law. This research indicates that the slag fertilizer can be applied to soils.

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Understanding the formation mechanisms of dioxins is indispensable to develop control technologies to minimize their emission from furnaces. Combustion experiments in a laboratory-scale fluidized-bed reactor using model wastes were conducted to investigate the influence of the oxygen concentration of primary and secondary air on PCDD/F formation. The concentration was adjusted between 10 and 21%. Decreased oxygen concentration in the furnace promoted PCDD/F formation. The oxygen concentration of the primary air exerted a stronger influence on the amounts of PCDD/Fs formed than that of the secondary air. The homologue profiles and the proportions of certain congeners showed tendencies opposite to those of previous studies. This meant that they were not preferably formed through oxidation/oxychlorination and breakdown of carbon and polycyclic aromatic hydrocarbons in lower oxygen concentration in the furnace, although the formation of products of incomplete combustion was promoted.

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In the present work, the heat exchanging efficiency of a pilot-scale regenerative thermal oxidizer (RTO) during the thermal decomposition of volatile organic compounds (VOC) was studied using toluene as an example of a typical VOC under the following experimental conditions : raw gas mass flow rates of 1090-2550kg·h⁻¹, toluene decomposition temperatures of 973-1173K, honeycomb heights of 0.9-1.5m and valve switching intervals of 60-180s.
As a result, it was found that the thermal efficiency calculated from LPG fuel consumption and the decomposed toluene, gave a maximum value of 0.95 at a raw gas mass flow rate of 1810kg·h⁻¹ in a honeycomb height of 1.5m. Furthermore, it was found that a decrease in honeycomb height from 1.5 to 0.9m caused insufficient preheating of the raw gas, which resulted in an increase in the concentration of toluene necessary in the raw gas from 340 to 530ppm to achieve self-combustion of the toluene without additional heating by LPG fuel.

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Hydrolysis with cellulase (saccharification) and bioethanol production (fermentation) by Saccharomyces cerevisiae IR-2 strain was investigated in an onion. In saccharification, glucose and fructose increased with time and became a maximum at 20 hours, although sucrose decreased with time. In fermentation, the content of ethanol converted by S. cerevisiae IR-2 strain increased rapidly with time and became a maximum within 32 hours in solution with 14.8mg·mL⁻¹. The temperature of fermentation was optimal in the range of 30°C to 35°C. Findings show that the free cells of S. cerevisiae IR-2 strain do not recognize ethanol production in simultaneous saccharification and fermentation. On the other hand, the immobilized cells of S. cerevisiae IR-2 strain note ethanol production in simultaneous saccharification and fermentation. These results suggest that simultaneous saccharification and fermentation by immobilized cells was useful for ethanol production in an onion.

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Inhibitory characteristics and process indicators were studied in laboratory experiments on the codigestion of cattle manure with organic cosubstrates using digesters with effective volumes of 6 litters maintained at a mesophilic temperature of 37°C and with hydraulic retention times of 30 days. Bread crumbs, butter and protein supplements were used as cosubstrates. We found that carbohydrates, lipids and proteins inhibited the digestion differently when used as cosubstrates. Codigestion with bread crumbs resulted in the accumulation of total volatile fatty acids (TVFA), which caused a 25% decrease in methane gas production at 4430mg/L. Codigestion with protein supplements resulted in the accumulation of both TVFA and ammonia, which caused a 25% decrease in methane gas production, at 9210mg/L and 5550mgNH₄-N/L, respectively. Codigestion with butter did not result in significant accumulation of TVFA. In the case of codigestion with carbohydrates and proteins, both methane gas production and TVFA can be utilized as process indicators of the inhibition of digestion. However, they did not indicate process imbalances in the case of codigestion with lipids.

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