Catalytic dechlorination of polychlorinated biphenyls (PCBs) using Pd coated Fe was examined to investigate the parameters for designing permeable reactive barriers (PRBs) to treat PCB-contaminated groundwater. The Pd coated Fe of various Pd loading rates of 0.01%, 0.03%, 0.06%, and 0.3% onto Fe (0) were tested with the initial concentration of 20mg/L of Aroclor-1254. Congener-specific analysis was conducted to compare the total and congener-specific dechlorination rate of PCBs using high resolution mass spectrometer (HRMS). Using 0.3% Pd coated Fe, Aroclor-1254 of 99.98% was dechlorinated down to 0.005mg/L within 120hours. The Pd coated Fe is suggested to be a promising reactive material for PRBs to treat the refractory contaminants such as PCBs in groundwater.

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Surface characterization for catalytic dechlorination of polychlorinated biphenyl (PCB) using Pd coated Fe was examined with three different surface profiling techniques. Investigation was made to characterize the surface of Pd coated Fe using X-ray Photoelectron Spectroscopy and Electron Probe Microscopic Analyzer. Scanning Probe Microscopic study was also performed to investigate the surface morphology of Pd coated Fe. Results indicated that the Pd was exist as in the form of the Pd(0) cluster on the Fe surface, and hydroxylated oxide layer could be formed along with the PCB reduction process. SPM results also showed that the pits existing on the surface of Fe were performed as the reaction sites. The result of this study can be applicable for improving the efficiency of permeable reactive barriers.

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In many countries, the leaded gasoline regulation has been carrying on these years to prevent the airborne lead related health risks. In this study, the Malaysian leaded gasoline regulation was examined from the viewpoint of the health risk reduction. The lead exposure to reference Malaysian was evaluated through the both pathways of dietary and respiratory intake, and the lead concentration in blood (PbB) was estimated by using the physiologically based pharmacokinetic model (PBPK model).
Consequently, the present lead exposure level of Malaysian is low enough for keeping PbB under the limit concentration of 30μg/dL. Most of Malaysians are holding PbB under the lower limit of 10μg/dL.

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The effect on the recreational activity of promoting the water environment improvement of Lake Biwa was quantitatively examined. A questionnairing for the people of Lake Biwa and the Yodo River basin was carried out. Willingness to pay of a visit to Lake Biwa before and after the improvement of aqueous environment was 507 yen and 721 yen, respectively. It was shown that the effect of water environment improvement of Lake Biwa was geographically very wide. It was also evaluated that the population where people would like to visit Lake Biwa increases at approximately 4 times. It was pointed out that the effect of water environment improvement of Lake Biwa on the behavior of people would be very wide in the basin.

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Continuous culturing for hydrogen production using L-lactate as substrate was investigated for the construction of hydrogen recovery process from mixed organic acid waste by Rhodospirillaceae. Reactor no. 1 under axenic condition had produced hydrogen at the rate of 16ml/h/l-reactor steadily. In reactor no. 2 to which non-sterile medium was supplied under axenic condition. hydrogen production rate dropped suddenly at after 400hour-cultivation. The drop of hydrogen production was due to the inhibitory afffection of the growth of algae. In reactor no. 3 in which the mixed culture was inoculated, hydrogen production was inhibitted owing to hydrogen sulfide produced by sulfater reducing bacteria (SRB). The competition among microorganisms appearing in the reactor was discussed in this study.

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We have evaluated three public works for environmental improvement of the urban river by “Eco-efficiency”. The “Eco-efficiency” is evaluated with four factors. They are willingness to pay, increase amount of visit, environmental loads and cost of the project. In order to uniform inhabitant's images about these environmental improvement project, we showed photomontage of the future urban river condition after implementation of the project. Using the photomontage, we researched WTP and increase of frequency of visit. And we estimated life cycle cost and lice cycle CO₂ of the projects. As a result, the construction of the river water direct purification system had the best “Eco-efficiency”.

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Trihalomethane formation potential (THIVIFP) and water quality of leachate from municipal solid wastes landfill site was investigated for 4 years. Calcium and manganese ions, which determine hardness of water, decreased enough in the leachate treatment process; however, high concentrations of sodium, potassium, and chloride ions were detected in the discharged water. Bromide ion concentration in the discharged water was 2-3 orders higher than in a reservoir for drinking water, which may increase bromate production during ozonation. THMFP in the discharged water consisted of mainly bromide compound, and was 335μg/l on an average and 1, 530μg/l at a maximum.

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Influence of sludge ratio and temperature on the integrated methane fermentation of organic fraction of municipal solid waste (MSW) and bio-sludge was investigated by using a semi-continuous flow completely mixed reactor. As the sludge ratio in the influent total solid (TS) increased from 0% to 50%, the degradation efficiency of TS decreased from 74% to 30% under thermophilic condition (55°C), and decreased from 67% to 30% under mesophilic condition (35°C). For maintaining high rate methane fermentation, addition of minerals to the feed was necessary for the MSW-rich cases when the sludge ratio in the influent TS was lower than 10%, although successful operation was possible without mineral addition when the sludge ratio was higher than 25%.

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This paper quantifies environmental load of road works and total material flow of roads in Japan. We develop a mathematical model that calculates material flow of roads in Japan based on the ratio of two types of road repairing works: replacing and resurfacing. Total material flow is strongly influenced by the introduction scale of resurfacing that has the lower environmental impact. From the material balance of construction wastes, it is clarified that the road is just a temporal stock of construction wastes and the increase of resurfacing is effective to reduce the net construction waste from roads.

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In order to evaluate annual dynamics of biomass for benthic faunal community, the ecological parameters (Carrying Capacity, K; Specific Growth Rate, r; Oscillation Intensity, s) of benthic faunal communities at the 70 river sites in the Tokyo metropolitan area were estimated. As a result, the value of K, r, s were in the range of 54-79479[mg/m²], 0.02 -6.40 [/year], and 0.13-5.85 [-], respectively. The statistical analysis revealed the two parameters, K and s, were related to physical and chemical factors in their habitats (e. g., dissolved oxygen and suspended solid concentrations, and discharge).

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A successful prevention of algae adhesion and growth using thin film photocatalysis has been demonstrated in a continuous flow bench-scale photo-catalyzed reactor. The effect of UV or BL exposure on photo-dependent denitrifying sludge (PDDS) and algae coexisting in the reactor were investigated. Even though algae adhesion could be controlled by thin film photocatalysis with UV, the negative effect on PDDS was negligible and continuous biodegradation of Acid blue 92 was significantly improved.

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The soil as a material of planting ground in a slope seeding needs proper organic factors for growing plants along with a stable slope that prevents erosion caused by rainfalls. For this reason, pH, hardness, and water content of soil were measured. In addition, C/N ratio, a degree of growth, and a stability of slope were measured for vegetation. In the experiment, a hardness value of soil indicated a range, which did not affect the growth of plants. Moreover, the slope did not show a surface erosion due to a rainfall. Furthermore, vegetation grew favorably and a rate of covering became 100%, and this contributed to the stability of a slope. From these results, it was concluded that waterworks sludge should be used in practice as a material of planting ground in slope seeding.

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A combination of geographic information systems (GIS) and a case-control study was conducted to identify environmental risk factors for cancers in the Tokyo suburb area from 1998 to 2000. GIS were used to correlate cancer mortality with proximity to a waste landfill site and calculate odds ratios (ORs) and associated 95% confidence intervals (CIs) for each site of cancer. Our findings indicated that a waste landfill site was the significance of the environmental risk factor for cancer mortality in the study population; local residents who live near a waste landfill site might have been at excess risk of cancers.

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A novel wastewater treatment system was proposed by a combination of an UASB reactor and an aerobic biofilm reactor. A laboratory-scale combined system was operated for 214 days by feeding a synthetic low-strength wastewater (300mg-CODcr⋅L^-1, simulating domestic sewage). The combined system exhibited a very satisfactory performance in organic removal, achieving above 92% CODcr removal at a HRT of only 4.5h under temperature range of 25°C through even 3°C. The system also accomplished a significant extent of nitrogen removal, more than 68% of T-N removal at above 7°C at a circulation ratio of 2 (the effluent from the aerobic biofilm unit was recycled to the UASB unit), and major organic removal can be attributed to denitrification, rather than to methane production or to sulfate reduction.

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A questionnaire was set out for the survey about the influence of a suspension of water supply on residents in Geiyo islands that were attacked by the 2001 Geiyo earthquake. Labor and time needed for obtaining water and additional time used for water consuming domestic activities as well as an additional expense under the condition of emergency water supply were quantitatively examined. These results can be used for making countermeasures against failure of water supply induced by earthquake and evaluation of their benefits.

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This paper presents the fast attempt to estimate the environmental value of restoring the eco-system of the Isahaya Bay Wetland by using the Contingent Valuation Method (CVM), in the three cities of Kyushu- Isahaya, Nagasaki and Kitakyushu. Mail survey technique and double bounded dichotomous-choice (DC) format have been used for eliciting willingness-to-pay (WTP). From the results of the study we have found that, the Isahaya Bay Wetland is worth approximately 218 million yen, 1.1 billion yen and 2.7 billion yen to the residents of Isahaya, Nagasaki and Kitakyushu, respectively. The study also revealed that, average willingness to pay of the respondents rises as the distance from the project site increases and gradually settles around a certain average amount.

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Cold Circulation Freeze-Drying Equipment of a pilot plant was produced to freeze-dry sewage sludge with a view to recovering cellulose of a biomass resource. The recovery yields of solids and water by the produced equipment were 90.0-96.0% (w/w) and 170-250% (v/v), respectively. The moisture content of the dewatered sewage sludge was about 12%. The cost of the freeze-drying treatment for sewage sludge was estimated to be approximate for present sewage sludge treatment using liquefied natural gas (LNG) waste cold heat. These results also suggested that freeze-drying treatment for sewage sludge did not occur by-products (dioxin, etc.) derived from incineration.

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