A batch type activated sludge process was applied to pyrene and 1-aminopyrene with and without humic acid addition. Pyrene, one of the most hydrophobic organic micropollutants, was not decomposed and more than 80% of initial dose was sorbed onto activated sludge regardless of humic acid addition. On the other hand, 1-aminopyrene recovered from the sludge phase decreased and unknown fraction considered to be contribution of decomposition or volatilization increased as time passed. We also observed a important role of humic acid for both of micropollutants to increase not only sorbed fraction onto concomitant natural organic matters including humic acid but also free micropollutants in aqueous phase. In addition, a mathematical model on the fate of the organic micropollutants was formulated on the basis of measured sorption coefficients and its accuracy was evaluated.

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The mechanism which causes upwelling of anoxic bottom water (Awoshiwo), often occurs in the north-eastern coast of Tokyo bay during summer and early spring is analyzed by using a three dimensional circulation model (Blumberg and Goodrich Model). We showed that northern wind generates a flow directing to south-west at the surface and one directing to north-east at the bottom of the bay inducing upwelling at the north-eastern coast of Tokyo bay. We also demonstrated that northern wind accelerates the vertical mixing by cooling sea surface which enhances instability.

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The numerical simulation was carried out for the analysis of water quality, sediment quality and release rate of nutrient from sediment at Tokyo port which is located at bay head area of Tokyo bay by the water and sediment quality model. As the results of the simulation, it was confirmed of their characteristics of seasonal and spatial variation. Next, the effect of pollutant load reduction on water quality and release rate of nutrient from sediment was analysed. As the results of the analyses, it was confirmed that the reduction rate of water quality and release rate of nutrient from sediment were smaller than that of pollutant load and the response of water quality and release rate of nutrient from sediment was linear for the pollutant load reduction.

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Fluid mechanism in an air-lift draft tube type sewage treatment reactor, which is operated under the conditions of low gas flow rate based on cross sectional area of the reactor (U_go) and low ratio of draft tube diameter to reactor diameter (D_i/D_o), was studied theoretically and experimentally. Empirical equations of gas hold up, pressure losses and liquid velocity in the draft tube were developed. It was found that liquid flow rate (Q_L) is almost proportional to the ratio of cross sectional area of the draft tube to that of the reactor (A_i/A_o). It was also found that under the conditions of U_go from 0.0005 to 0.005m³/(m²·s) and of A_i/A_o from 0.02 to 0.14 circulating time in the annulus is almost proportional to the ratio of the cross sectional area of the annulus to that of the draft tube (A_a/A_i).

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The treatment of humic and fulvic acids extracted from leaf mold, sludge in grit chamber, and bottom sludge in river by the various Advanced Oxidation Processes (AOPs) centered on ozonation showed that the origins of humic and fulvic acids were not important factor for the mineralization by hydroxyl radical (·OH). On the other hand, the formed substances by the oxidation of humic and fulvic acids or compounds having benzene nucleus as Lignine or p-Hydroxybenzoic acid with·OH showed that had same characteristics of dicarboxylic acids on Size Exclusion Chromatography (SEC). The result suggest that the oxidation of benzene nucleus or ozonation product of benzene nucleus significantly affect mineralization of humic and fulvic acids.

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A study was conducted to investigate the diffusion prevention procedure of non-biodegradable organic contaminants in groundwater by installing powdered activated carbon mixed CB cut-off barriers. Diethylene and polyethylene glycols were applied as the indicating contaminants. An estimation on the diffusion prevention ability was carried out applying advective diffusion equation. As the results, the reaching periods to breakthrough for 100 years or longer were estimated on the contaminants having approx. 200 to 1000 of molecular weights and for 40 years or longer was also estimated on the contaminants having approx. 100, when assuming both 1.0m in thickness of the cut-off barriers constructed and maintaining 0.1 of the hydraulic gradient.

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The authors have developed a novel membrane process in which ammonia oxidizers are fixed on the membrane disk. In this study, the characteristics of the membrane filtration resistance was investigated. The results derived from this study were summarized as follows: (1) The magnitude of the filtration resistance was strongly affected by the initial inoculation. (2) The filtration resistance due to the accumulated cake was found to be dominant. (3) Increasing the disk rotational speed was found to be efficient for removing cake. About 3000 hours of the operation could be continued by only implementing this simple cleaning method every 500 hours. (4) Filtration resistance excluding the cake resistance seemed to be caused by humic substances and extracellular polymeric substance produced by biomass.

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This paper describes the results of the comparative study on quantitative evaluation of urbanization using satellite data for four Asian cities which are in different developing situation. In the previous paper the authors proposed urban index UI which is estimated from Landsat TM image. In this study the applicability of the index UI for different regions and seasons was examined at first. Then the relation between urbanized area and vegetation area was compared for the four cities, using UI and NDVI. Finally the distributions of urbanized area in the cities were compared applying join value analysis. As the results of the analysis, two different types of urbanization were recognized quantitatively.

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