In this study, application of immobilization of E. coli JM109 (pUCDEXL) introduced recombinant plasmid DNA coding 2-halo acid dehalogenase gene from Burkholderia cepacia KY and its effect on the microbial activity were discussed. E. coli JM109 (pUCDEXL) was immobilized with agar, polyvinyl alcohol and acrylamide. The activity was comparatively higher, but some leakage of E. coli JM109 (pUCDEXL) was found in case with polyvinyl alcohol. Although the remaining activity was rather lower after immobilization, the cell was sufficiently held in acrylamide. Immobilization was effective in the reaction at pH8-10. Dehalogenase activity in immobilized E. coli JM109 (pUCDEXL) sustained longer than free cell. These results suggested the possibility that immobilization could improve stability of genetically engineered microorganisms for bioremediation.

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As an attempt on the estimation of the permissible load to enclosed coastal sea, we showed the difference in the characteristics of the eutrophication on each bay and the estimation of the permissible load of TN and TP by using the correlation figure of the loads of TN and TP per unit area and the product of the average water depth and the renewal rate. These results of the study can contribute to the proposition of the water quality improvement plan accoding to the characteristics of the bay.

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Land subsidence and saltwater intrusion into groundwater due to pumping up of the same are examples of the serious problems in this region. It is important to study on the characteristics of groundwater environment for conservation of geoenvironment. Recently, the tracer methods using such dissolved elements as cations/anions and gases, natural radioactive or stable isotopes have been used widely for study on groundwater circulatioa This paper describes the applicability of these tracer methods in Saga Plain. The results show that the groundwater in Saga Plain has been supplied from the surrounding mountainous districts. This study also shows that the age of groundwater at the foot of mountains is several decades, and that of the plain near Ariake Sea is about 10³ years long.

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This study attempts to establish a method to predict human comfort for outdoor environments using a neural nerwork. First, the correlation between physical properties which represent outdoor environment and sensations corresponding to thermal, sound, visual and air environments was investigated to derive indices appropriate for the inputs to a neural network. Then, a neural network was successfully applied to predict human comfort with the error of about 9% for non-learning data. The sensitivity analysis of the neural network showed that the human comfort is sensitive to aethetic of landscape, temperature index, natural sound index, sky vew factor and odor index in the order of appearance under avegare conditions of combined environment.

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A laboratory study on confining treatment in situ for Cr (VI) compound contaminated soil by applying a deep mixing stabilization process was conducted using either slug-cement type B with sodium base bentonite (CB mixture) or slug-cement type B only. There were found that 50mg/kg (dry-base) of Cr (VI) contaminated sandy and organic soils could be kept lower than the established leaching concentrations by the environmental quality standard on soil by dosing 200kg/m³ and 100kg/m³ respectively of slug-cement type B, and the confining effect was recognized at slurry type superior to powder type. There was also found that the mixing efficiency of mixed slurry samples could estimate by measurement of lightness on affecting Cr (VI) leaching concentrations with the difference between strength of the mixing. It was required that the coefficient of variation on mixing efficiency was 2% or less for a most effective confining treatment, which the cement stabilizer can be distributed uniformly in Cr (VI) contaminated soil mass in situ.

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The values of dissolved oxygen, COD, Ignition Loss, Sulfide and Redox (Eh) in the Kasai artificial beach show almost same values as those of Banzu flats and Sanbanze, natural tidal flats in Chiba Prefecture.
However, the fluctuations in the biomass and species of the macrobenthos are so high that it cannot be considered a stable system. Those fluctuations are explained by factors such as the influx of river water. When the river water has been increased by rainfall, the water quality in Kasai artificial beach becomes a low salinity, and it was guessed that bivalves of Ruditapes phitippinarum, Mactra veneriformis, Mactra chinensis, etc. in the macrobenthos which are weak to the decrease of salinity, have been suffered big damage by low salinity.

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The three kinds of experiments using garbage disposer wastewater were performed to measure their physical and chemical characteristics for wastewater treatment: (1) settling test of suspended solids; (2) characterization of organic matters; and (3) thickening test of sludge. Settling test showed that the about 65-75% of suspended solids could be treated in the primary settler. Characterization of organic matters indicated that about 85% of organic matters in garbage disposer wastewater was slowly biodegradable, and that non-bio-degradable portion was little. Thickening test showed that settling velocity was controlled mainly by the concentration of primary sludge.

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When an intestinal infectious disease is outbroken in a city, the water environment receiving the effluent from the wastewater treatment plant in the city will be polluted by the pathogen without the appropriate treatment. In such cases, there is possibility that the outbreak of waterborne infectious disease occurs in other cities using the water environment as the source of drinking water. In this paper, the propagation model on outbreak of waterborne infectious diseases between two cities in the watershed was developed taking some factors (pathogen removal efficiencies by water and wastewater treatments, the river flow rate, the pathogen concentration in the river, and so on) into account. The outbreak propagation coefficient (OPC) was very available for the watershed management from the viewpoint of public health.

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This study provides an integrated modeling approach of free water system constructed wetlands by considering dispersed flow conditions of the wetlands, and contribution of suspended biomass in bulk liquid phase and biofilm biomass attached on various surfaces in removing the organic matters. Model parameters such as kinetic and dispersion characteristics, biofilm thickness, and density were obtained experimentally. A significant role of attached biomass was established. The model was validated with the data obtained from a pilot-scale plant and compared with other existing plug-flow models and found more applicable in wetland design.

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A comprehensive field monitoring and laboratory measurement of water quality of a river in Bangladesh was undertaken from January to April in 1995 and 1996. Subsequently, 1-D water quality model was developed, calibrated and verified with the collected data to quantify the state of pollution and the assimilative capacity of the river during the low flow period. The study indicates that the DO condition of the river water remains above the critical level of 4.0mg/L, supporting the survival of aquatic life including fish. The river still has significant assimilative capacity and can assimilate the waste load from future new industrial establishment without violating the DO standard.

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The objective of this work is to investigate the effect of oil fraction (θ_O) on optimal salinity (S) and minimum water-oil interfacial tension (γ_min). The results reveal that S and γ_min are changing upon changing θ_O. These results are in agreement with that of the column experiments. The formulation optimized at θ_O equal to degree of oil saturation present in the column shows highest efficiency for oil recovery. The change of S with θ_O is described through the coefficient of oil fraction (k_a), however, this change does not affect the parameters of the correlation between S and γ_min found in our previous study. These findings provide an useful tool for the selection of surfactant formulations for soil remediation.

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Recently, it is important aim that the river environment is preserved in the river and sabo works. However, the constructions maintained harmony with the environment were hardly estimated objectively.
The author examined the assessment method of natural environment, utilizing fractal concept. As the result, there is a difference between the natural aspects and artificial aspects for the riverbed materials and vegetation, using the fractal property and Hopkins-Skellam Index. Through this study, the assessment method of naturalness for the river environment elements is suggested. And, the vegetation distribution is quantitatively estimated, exploiting fractal dimension and distribution area.

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