Leachability and mobility of heavy metals in contaminated soil depend on their specific chemical formations. In this study, the modified BCR sequential extraction method was applied, in which two extraction procedures with distilled water and acetic acid are added to the standard BCR sequential extraction procedure, in order to determine the chemical forms of lead (Pb), fluorine (F) and mercury (Hg). As the results, the distributions of each fraction for these heavy metals were determined and the chemical forms of these heavy metals were estimated. By comparing to the results of JLT (Japan leaching test) -46 and NEN7371, the ratios of heavy metals with long-term leaching were determined.

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Soil washing is an ex situ cleanup method of soils contaminated with a variety of chemicals, such as heavy metals, fuels, and pesticides that can sorb to the fine-grained soils like silt and clay. Contaminated soils are separated into two parts by soil washing, clean reusable sand and highly polluted sludge for further treatment or disposal. At the end clean sand is tested for residual heavy metals by soil leachate and content tests.
The corelationship between the total heavy metal content and the leaching value in clean sand is only weakly positive. It is due to the fact that heavy metals of different chemical species, such as exchangeable/acid-soluble (carbonates), reducible (Fe and Mn oxides), oxidizable (bound to organic matter or sulphides), and residue, have different characteristics.
This is an experimental study of a soil washing system consisted mainly of hydrocyclone and flotation processing. Lead and fluorine, two most typical contaminants, were examined. Firstly, lead and fluorine samples before soil washing were fractionated for each soil particle size group. Secondly, each sample at every stage of soil washing was fractionated, i.e., feed, underflow of hydrocyclone, overflow of hydrocyclone, flotation froth and clean sand. Fractionation was carried out by using the modified BCR sequential extraction procedure that is capable of separating samples into five chemical parts, water-soluble, acid-soluble, reducible, oxidizable, and residue fractions.
The flotation process was reducing not only the heavy metal content in the feed soil but also the mobile fractions (water-soluble and acid-soluble) related to the leaching behaviour of clean sand. As a conclusion, information obtained by the modified BCR sequential extraction procedure will be used in making judgement how much heavy metal content related to leachability in clean sand will be reduced.

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Down-flow hanging sponge (DHS) reactor was applied for efficient organic removal and ammonium oxidation of high salinity wastewater. The combined DHS process which was made by connecting three identical DHS reactors in series was fed with an artificial coke-oven wastewater containing a large amount of phenol and ammonium nitrogen with high salinity. Organics were removed mainly in the 1st reactor while almost all of ammonium nitrogen was oxidized in the following reactors. As a result of microflora analysis, bacterial clones involved in nitrification were rather detectable in the 2nd and 3rd reactors than in the 1st reactor, suggesting that different microfloras were established along the DHS.

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Net CO₂ emissions reduction by utilization of forest trees as energy source was estimated in Japan upto 2050. The estimate involves not only CO₂ emissions reduction through replacement of the fossil fuel consumption, but also change of carbon storage of both in forests and wood in the buildings. The carbon storage decreased by planting and harvesting wood for fuel production in shorter cycle than the conventional forest management This study showed the importance of considering the impact on net CO₂ emissions reduction by such change of carbon storage. When conventional trees are planted and clearcut for bio-ethanol use as opposed to preserving forests, net CO₂ emissions increased over the long-term. In contrast, when fast-growing trees are planted and clearcut, net CO₂ emissions decreased after 2025.

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A laboratory-scale EGSB reactor was operated for 400 days to investigate the effect of a temperature decrease on the physical and microbial characteristics of retained granular sludge. The reactor was inoculated with 20°C-grown granular sludge and started up at 15°C. The influent COD of synthetic wastewater was set at 0.6-0.8 g COD/L. The process temperature was reduced stepwise from 15°C to 5°C during the experiment. Decreasing the temperature from 15°C to 10°C decreased COD removal efficiency. However, continuous operation of the EGSB reactor at 10°C led to an efficient treatment of wastewater (70% of COD removal, 50-60% of methane recovery). Unfortunately, at 5°C COD removal efficiency drastically decreased and the amount of removed COD dropped to half of that at 15°C. A decrease in sludge concentration and a major deterioration of the retained sludge's settleability were observed while the reactor was operated at 5°C. We confirmed the remarkable increase of methanogenic activity of retained sludge at 15-20°C due to the low temperature operation of the reactor. The increment of activity of retained sludge as compared with seed sludge was higher at 20°C for acetate (3.9 times higher) and at 15°C for H₂/CO₂ (6.4 times higher). Changes in the microbial structure of retained sludge with respect to Archaea were investigated by 16S rDNA-targeted DGGE analysis and cloning. This revealed that the genus Methanospirillum, a hydrogen-utilizing methanogen, proliferated. An expected decrease in some Methanobacterium spp. due to low temperature operation of the reactor occurred. On the other hand, genus Methanosaeta was abundant as an acetoclastic-methanogen throughout the experiment.

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