Occurrence of chlorate and perchlorate in groundwater in Tokyo was investigated. The samples were collected in 2007 and 2009. Chlorate and perchlorate were detected at the concentrations larger than their determination limits in 24 of 49 and 28 of 52 samples, respectively. Their detection rates in unconfined aquifers and springs were higher than those in confined aquifers. The concentrations of chlorate and perchlorate in about 25% of samples were relatively high, particularly chlorate concentration in one sample (2000 μg/L) exceeded its standard value in drinking water. Compared to other groundwater in Japan (i.e., commercially available natural water and raw water in private water supply), the percentages of the samples with relatively high concentrations of chlorate and perchlorate were higher in groundwater in Tokyo. On the other hand, the percentages of the samples in which chlorate and perchlorate concentrations were larger than determination limits were the lowest. The medians of chlorate and perchlorate in the in groundwater in Tokyo were similar to those in other groundwater in Japan. It was suggested that origins of chlorate and perchlorate in groundwater were drinking water and/or sewage in many cases when their concentrations in groundwater were relatively high.

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 The arsenic contamination of soil causes a huge damage on human health and production of food. In this study, the arsenic pollution of the sea shore areas of Miyagi Prefecture, Japan, where marine sediment was brought onto the land surface by the 2011 off the Pacific coast of Tohoku earthquake tsunami was investigated. Seventy eight soil samples were collected from both the tsunami disaster regions and the non-tsunami disaster regions of each major river alluvial plain in Miyagi prefecture. The arsenic contents of those soil samples were analyzed by an atomic absorption photometer. The results showed that in each river alluvial plain, the average of the arsenic content of the tsunami disaster region soil is higher than that of the non-tsunami disaster region. Furthermore, the arsenic content of each alluvial plain soil and the tsunami deposit reflected on the geological features and the anthropogenic activities (mining, hot spring, etc.) in the river basins. These results suggested that the arsenic contamination of the soil of major river alluvial plains that were suffered from the tsunami disaster was enlarged by the tsunami deposit which accumulated arsenic in the marine sediments during long time period of the river flows.

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 The loading and removal of PAHs were measured and estimated in a sewage treatment plant in a suburban, separate sewer area in Japan. The inlet 16PAHs concentration was 218 ng L^-1 , whereas the discharges concentration was 42.9 ng L^-1 . No clear diurnal and weekly fluctuation was observed. For long-term changes, fluctuation continuing more than a week was observed for PAHs concentration. The PAHs were decomposed or vaporized in the treatment plant in a half, and the rest is discharged into the outlet or excess sludge evenly. The level of measured inflow concentration and loading were considered to be in the lowest among other researches. The overall loading of PAHs from sewerage in the separate sewer area to the water environment was considered to be lower.

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 In this study, reduction of greenhouse effect gas in Amakusa City, Kumamoto, was estimated by assuming several scenario of disposal and recycling of unused biomass waste. The population of Amakusa City is approximately 90,000 people, but because Amakusa City was born by a merger, there are five incineration facilities and three sewage treatment facilities. In this study, three scenarios were supposed: composting, methane fermentation, and composting plus methane fermentation. Old incinerators and sewage treatment facilities were rebuilt as the central facility, and windrow type composting of animal waste was changed to aerated composting. As a result, it became clear that introduction of the methane fermentation was effective in reduction of the greenhouse gas because of energy recovery as electricity and high emission from composting due to nitrous oxide emission. The effect of uncertainty in emission factors which are commonly used for greenhouse emission, and variability consumption of fuel and electricity in facilities were also discussed.

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 An electrolytic crystallization reactor was installed at a small-scale pig farm. Using the effluent from the activated sludge process treating the actual livestock wastewater, the continuous pilot-scale experiments were carried out to evaluate nutrients removal efficiencies of the electrolyzer. It could be confirmed from the experiments that crystalline substance was generated around the cathode through the electrolysis and thereby effluent concentrations of nutritive salts were decreased. The nutrient removal rate was changed depending on the influent load of nutritive salts, applied electric current and interval of polarity reversal. The crystalline substance recovered contained phosphorus, potassium, magnesium and calcium in large quantities. The results suggested that hydroxyapatite (HAp) and magnesium phosphate (MP) might be simultaneously formed through the electrolysis.

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