Compact composting equipment is gradually gaining popularity among businesses that generate food waste and households. These machines are equipped with turning devices and they turn compost materials intermittently in order to maintain aerobic conditions. Turning consumes energy, so its frequency must be considered carefully. In this paper, we present a simulation method to estimate the oxygen concentration profile of static piled compost materials. The simulation is based on the idea that the change in oxygen concentration is driven by the diffusive oxygen supply from the surface of the material and the oxygen consumption of the material. We prove the validity of this method by comparing its results with the results of column experiments. We also present examples of the application of this simulation to determine adequate turning frequencies.

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In order to get the current picture on End-of-Life Vehicles (ELVs) leaving Japan internationally, this paper defines three types of international export categories : business export, holding export, and other. Using trade statistics provided by Japanese customhouses, an attempt was made to estimate the volume of ELVs exported from Japan as used vehicles, used parts, and secondary materials for each category of export between the years 1988 and 2005. The results of this estimation showed that the volume of Japanese ELV exports increased by more than 3 times, from 863000 tons in 1995 to 2635000 tons in 2000. Furthermore, the paper determines that used vehicle rates were 51-63% ; used part rates were 36-48% ; and secondary material rates were always 1% for ELVs during this time period. About 15-34% of the ELVs from Japan were holding exports and other exports, data that is not easily obtained from trade statistics.

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The characteristics of riddling ash from stoker-type municipal solid waste incinerator were investigated. The contents of Cu, Zn and Pb in riddling ash were greater than that in other MSWI residues, and the contents of precious metals, such as Au and Ag, were nearly equal to their ores. There was a correlation between grate type and the contents of Cu, Zn and Pb in riddling ash. The contents of Cu, Zn and Pb in riddling ash for the reciprocating flat grate type were greater than that of the parallel swing grate type. It was confirmed that 20-60% of Cu, Zn and Pb in MSW were discharged as riddling ash. Analysis by XAFS spectroscopy at beam line BL01B1 in SPring-8 led us to consider that the predominant chemical states of Cu, Zn, Pb and Ag in riddling ash under drying and combustion zone are metallic states. It is considered possible for riddling ash to be come a source of non-iron materials by separating it from bottom ash because of the large amounts of Cu, Zn, Pb and precious metals contained in it.

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The leachate samples from 22 landfill sites for municipal solid waste (MSW) in Saitama prefecture were analyzed for 46 parameters in the years 2000 and 2005. Five parameters (pH, Cd, Pb, BOD and Fe) exceeded the standard values set by the government for final effluent. The correlation analysis for these 46 parameters showed high correlation coefficients among the organic parameters of BOD, COD, TOC and volatile fatty acids (VFA), and among the inorganic parameters of EC, Na, K, Ca and Cl^-. The principal component analysis for these nine parameters showed that the primary component represented the total amount of chemical substances and the secondary component represented the organic or inorganic nature of the leachate, and that these two components were applicable to the classification of the surveyed landfill sites. In addition, in the landfill sites for MSW that accept mainly incineration residue, it become clear that the EC value can be applied to monitor the fate of BOD in the leachate after landfill input has stopped and to predict the occurrence of high concentrations of heavy metals like Pb in the leachate of a specific landfill site.

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We investigated the hydrogen production potentials of carbohydrate, protein and lipids through batch experiments at 35°C. We obtained eight different seed microorganisms from a thermophilic acidogenic reactor, a thermophilic anaerobic digester, a soybean silo, an organic fraction of municipal solid waste (OFMSW), cattle manure, activated sludge and soil. We used starch, peptone and oil as representative substrates for carbohydrates, proteins and lipids, respectively. Hydrogen production potentials of starch were significant and ranged from 17.8 to 186 mL H₂/g starch. Peptone and oil had low hydrogen production potentials. We analyzed the microbial communities after batch experiments using starch by the PCR-DGGE method. We observed typical hydrogen producing bacteria of the genuses Clostridium and Citrobacter in the various kinds of waste biomass, including the OFMSW. This research shows that safety management of unintentional hydrogen production from waste biomass is important.

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The biodegradable garbage decomposer is expected to become an approach for effective utilization of forest products, such as thinning cuts, using matrices prepared from wood. The machine has not been popularized, however, due to the inconvenience of frequently having to renew the matrix, and the unpleasant odor. Since such problems may be being triggered by a low pH in the matrix, CaCO₃ was added to the wooden matrix as a pH stabilizer in this experiment. Addition of CaCO₃ made it possible to maintain the pH in a neutral region during a four to five month period. It also resulted in a longer lifespan for the matrix and suppression of the formation of volatile fatty acids.

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The present study investigates the moisture content of stem and woody biomass evaluation in logs with small diameters obtained from the first thinned 26-year-old Sugi (Cryptomeria japonica D. Don) seedling plantation in a standine with varying slopes. The standine was classified into three slopes : the lower part characterized by a flat slope ; the middle part with a moderate slope ; and the upper part with a steep slope. A comparison of moisture content in the stem and woody biomass accumulation was performed among samples from the three plots. The average wood density in the oven-dried condition and moisture content of the stems were at 0.31 ton/m³ and 66.2%, respectively. Statistical differences in wood density, and moisture content of the stems among the samples from the three plots were determined by an analysis of variance. Both traits were found to be of no significance among the three plots. Moisture content of the stems was found to have no correlation with the diameter at breast height (DBH), while woody biomass accumulation showed a good, positive significant correlation with DBH. Woody biomass accumulation from thinned logs ranged from 26.60 to 36.69 ton/ha with average 31.30 ton/ha. In addition, the woody biomass amount showed a trend to increase from the upper plot to the lower plot. Thus, moisture content of the stems shows an independent trait, from DBH and plot. Results indicate that woody biomass can be evaluated from a stem-radial growth of the trees, irrespective of plots with different slopes.

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