Many existing anaerobic digesters in sewage treatment plants have surplus capacity because they are operated at quite long retention times. Thus, anaerobic co-digestion of sewage sludge and other biomass using existing digesters may be an attractive method for the efficient biogas recovery from biomass. In this study, we focused on rice straw as unused resources and investigated the feasibility of anaerobic co-digestion of sewage sludge and rice straw. As rice straw is too solid to feed directly in anaerobic digestion, two pretreatment methods, physical ground and thermal pretreatment were examined. After pretreatment of rice straw, mesophilic digesters were operated at various mixture ratios of rice straw to sewage sludge at retention times of 30 days. The results were as follows; rice straw didn't have inhibitory effects on digestion of sewage sludge and stable digestion was achieved in all conditions; in order to get methane conversion from rice straw same as sewage sludge, mixture ratio of rice straw to sewage sludge was 1: 0.5 in physical pretreatment (5mm) and 1: 1 in thermal pretreatment (120°C, 15 min); COD concentrations increased whereas ammonia nitrogen concentrations decreased in the supernatant of digested sludge by feeding rice straw.

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The dilution-free treatment of the food-processing wastes by a two-phase circulating anaerobic process was investigated in this study. In this process, the food-processing wastes were diluted with the effluent from the methanogenic reactor instead of dilution by adding tap water. The potato waste and the soybean waste were used as the food-processing wastes. The C/N ratio was 32 and 13 for potato waste and soybean waste, respectively. The CODcr loading rate for the methanogenic reactor was 14.0 g/l/d for potato waste and 17.9 g/l/d for soybean waste. The methane content in biogas was 56% for potato waste and 62% for soybean waste. The high VS removal (89%) and total CODcr removal (88%) were achieved in potato waste treatment. On the other hand, the VS removal and total CODcr removal were 79% for the soybean waste. No ammonia inhibition of methane production was observed in soybean waste degradation at NH_4⁺ concentration of 3, 900mgN/L. However, acetate was significantly accumulated at higher than 4, 000 mg/L of NH_4^-N, indicating that the high concentration of NH_4^-N seriously inhibited methanogenesis.

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An anaerobic digestion process with ozonation was studied by conducting pilot-scaleexperiments for on-site reduction in withdrawal sludge quantities while improving the biogas recovery, using a mixture of primary and secondary municipal sewage sludge. High VSS digestion efficiencies of ca. 80% and corresponding much methane production were achieved at reactor SS concentration of 6.5%. An empirical first-order kinetic model reasonably predicted the VSS degradation rates in the steady state conditions. The model suggested that about 61-70% of VSS fraction in the sludge was biodegradable nature and their specific degradation rate highly depended on the sludge source. The specific degradation rate in the model was 0.243 day^-1 (primary sludge), 0.101 day^-1 (excess sludge) and 0.019 day^-1 (ozonated anaerobically digested sludge). In contrast of highly VSS degradation, solubilization of inorganic compounds was very limited and accordingly high fraction of inorganic solids, mainly acid insoluble inorganics and iron compounds, were found to accumulate in the reactors. The part of heavy inorganic solids could be removed by centrifuging and thus concentrated into the sludge to be withdrawn. The sludge having low VSS/SS ratio gave less moisture content of dewatered sludge cake. A linier relationship was found between VSS/SS ratio and the moisture content.

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A long-term continuous flow experiment was conducted to investigate the process performance of a thermophilic multi-staged UASB (MS-UASB) reactor for treatment of liquid fraction of an alcohol (Shouchu) distillery wastewater. A demonstration scale MS-UASB reactor having a working volume of 2.5m³ was operated at 55°C for a period of over 400 days.
Even though Shouchu distillery wastewater is a typical seasonal campaign wastewater, the process shows superior capability in re-starting up. The reactor steadily allowed a significant high COD loading rate of 60kg COD·Em^-3·Ed^-1, which is equivalent to the influent strength of 10, 000-20, 000mg COD·EL^-1 at an HRT of only 4-8h, keeping COD removal of above 80%. Methane gas concentration in the biogas was about 70-80% over the experimental period. A linear relationship (R²=0.99, 0.97) was found between removed COD and methane production (as a COD conversion value) in Phase 1 and Phase 2. The methane conversion ratio during continuous run with barley-made (Phase1) and sweet potatomade (Phase2) Shouchu wastewater were 95% and 91%, respectively.

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In order to improve the quality of sewage sludge compost products, hair-decomposing bacteria were isolated and investigate their function on composting process, because much human hair remaining in sewage sludge compost causes deterioration in quality. The isolated strains on the agar plates served in hair and keratin liquid medium for measuring the generated amino acid concentration and observing the situation of hair decomposition microscopically. Three strains, including Bacillus sp.(No.5) and two actinomycetes (No.9 and No.10) were obtained as promising bacteria and their characteristics were examined through four experiments. From the results of time course experiments, No.10 got the highest rate of amino acid production of 1.834 (g/L·Eday) from keratin. The temperature experiments showed that in the hair liquid medium the peak of the rate of amino acid production was at 25°C and the minimum was at 50°C. The falling rate of No.5 by the effect of rising temperature was smaller than other two. The coefficient dependent on temperature which was analogous to the activation energy in Arrhenius equation was introduced to evaluate the effect of temperature. In addition, the results of the mixture of experiments and the pretreatment experiments were discussed.

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During anaerobic treatment of solid wastes, relatively slow hydrolysis of organic solids is usually considered to be a rate-limiting step. In this study, alpha-amylase, one of the hydrolytic enzymes, was investigated for the elucidation of more precise mechanism on hydrolysis during solid waste treatment Alpha-amylase activity of solid starch-degrading bacteria (SDB) was investigated through batch experiments in mesophilic condition with several different substrates and with distinction between cell-bound and cell-free alpha-amylase. Four new strains of SDB were isolated successfully. Monitoring of the isolated bacteria was done by fluorescence in situ hybridization (FISH). Results indicated that cell-bound alpha-amylase was mainly responsible for the hydrolysis of organic solids, suggesting that increasing the contact between microbial cells and solid substrates might improve the digestion processes. It was also observed that during the absence of substrate, activity of alpha-amylase of SDB was low, however, it increased as substrates like starch or maltose was introduced.

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Influence of nitrogen and sulfate concentrations in wastewater on a purple non-sulfur bacteria (PnSB) pond process were investigated. A laboratory-scale chemostat photobioreactor treating four types of simulated wastewater were tested with different combinations of nitrogen and sulfate concentrations. Rhodopseudomonas palustris and sulfate-reducing bacteria were detected by a fluorescent in-situ hybridization (FISH) technique using specific probes, and their population was quantified by pixel counting in fluorescent microscopic observations. As a result, ratios of Rpal686 on EUB338 probe were over 25% throughout the operation period. Average removal of dissolved organic carbon was 94% independent of nitrogen and sulfate concentrations. However, it was found to be difficult to suppress sulfate reduction, even in case that nitrogen-limited wastewater was fed.

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A feasibility test of a 17m³ pilot-scale sewage treatment system was carried out by continuous feeding of raw municipal sewage under ambient temperature conditions. The system consisted of an UASB and an aerated fixed bed reactor as a first unit and as a second unit, respectively. A part of the effluentfrom the fixed bed reactor was returned to the influent of UASB in order to supply sulfate sources. The total BOD of 148-162mg/L at influent was reduced desirably to 11-25mg/L at final effluents with a condition of the overall HRT of 24hr and the recirculation ratio of 2-0.3 throughout the experimental period. The final effluent also showed superior quality with respect to low SS (10-32mg/L) and high phosphorus removal efficiency. Vial activity tests of retained sludge in the UASB was conducted to evaluate an impact of temperature on the activity of microorganism. The methane-producing activities from acetate and H₂/CO₂ gas at 10°C were only 2% and 0% of those at 35°C, respectively. On the other hand, sulfate-reducing activities of the UASB sludge showed relatively high at 10°C such as 18% for acetate and 9% for H₂/CO₂ gas compared to the activities at 35°C. Therefore, BOD oxidization by sulfate reduction in the UASB could be dominant rather than methane production under low temperature condition. This sulfate-reducing activity tended to be proportional to the copy number of adenosine-5'-phosphosulfate (APS) reductase genes in DNA extracted from the sludge.

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Composting toilet using sawdust as artificial soil matrix is an essential process in the onsite wastewater differentiable treatment system. It reduces volume of feces and urine by evaporating of water in feces and urine. And it can also attribute to nutrient recovery from human manure due to giving used sawdust that can be used as organic fertilizer rich in N, P and K. The aims of this paper are 1) to measure nitrogen balance in composting toilet and 2) to evaluate the effect of water evaporation on ammonia volatilization due to its high solubility into water. The nitrogen balance data obtained from the composting toilet operation showed that approximately 25% of nitrogen remained in the sawdust matrix and ammonia emission was always detected. The evaporation of water and ammonia volatilization occurred simultaneously from the composting toilet. In order to evaluate the effect of water evaporation onammonia volatilization, the time course of pH and ammonia concentration in sawdust matrix were observed during ammonia volatilization process with and without evaporation of water. In the experiments, the rate of ammonia volatilization was greater than the rate of water evaporation in the first period and then the rate of ammonia volatilization decreased and become lower than water evaporation. This change in ammonia volatilization was caused mainly by pH value of water in the sawdust Especially, at low water content the sawdust pH kept less than pH 6 even if ammonia concentration was high.

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We examined the characteristic of intermediate fermentation and ecological significance of microbe in thermophilic methanogenic system. Our study focused on ecological significance of sulfatereducing bacteria contributing to propionate degradation, and the effects of the operating parameters such as pH level, COD loading and sulfate concentration on propionate accumulation. Six CSTRs were operated at a temperature of 55°C and HRT of 25-75 days. The reactor “S-7” was placed as a control reactor, which was fed with starch as a carbon source under a constant condition of pH7, 33 mgS/L of sulfate, and COD loading of 1.2kg/m³/day. Other five CSTRs were operated at various conditions such as pH levels (pH6 to pH8), COD volumetric loading rate (3.0kg/m³/day), sulfate concentration (33 and 100 mgS/L), and feeding of protein as a different type of carbon source. As the results, propionate accumulation in the sulfate-rich reactor, “S-S”, was found at 100-200mg/L, which was 1/10 of the control reactor, “S-7”. Propionate-degrading activity test for sludge in “S-S” reactor with feeding of initial sulfate at 400mgS/L showed that the propionate-degrading activity was enhanced up to three-fold compared to one in “S-7”. Community structure in hydrolysis and acid producing processes was examined by domain bacterial 16S rDNA targeted PCR-DGGE analysis.“Band B” or “Band P” on PCRDGGE analysis found more starch- or protein-degrading bacteria, respectively, from all reactors. Fluorescence In-situ Hybridization was utilized for the identification of Thermophilic sulfate-reducing bacteria. By the analysis, Desulfotomaculurn sp. was found in all CSTRs.

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Dissolved nitrogen concentration of bulk precipitation and stream water were investigated on the Kabura river watershed (Western part of Gunma Pref.) and the Oze-numa lake. Also dissolved nitrogen concentration of stream (upper end of each river) around the Echigo Mountains including Fukushima, Niigata and Gunma Pref. were analyzed. NOx-N concentration showed most high value on the Kabura river watershed, and rather high value on the Tone river. In Niigata Prefectural side of Echigo Mountains, nitrogen concentration of the stream water lowered in 1/2 and in Fukushima side of that nitrogen concentration decreased to 1/5 level.
Rather high concentration of inorganic nitrogen on the upper stream of Tone River is thought to be derived from the air contaminants which comes flying from the metropolitan area with the sea wind in summer.

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Using tape type filter, an absorption photometer suitable for continuous absorptioncoefficient monitoring in remote area and black carbon (BC) monitoring in urban area was developed. This instrument is equipped with two fiber optic sensors, monitoring reflected light from aerosolcollecting spot and non-collecting part of the filter. The latter signal was used as a reference tocorrect the shift of the sensor sensitivity caused by temperature fluctuations. Collection spot was automaticallychanged when the signal from the spot decreased below a threshold value. Measurements were conductedin Sapporo in October and November 2003 (period-I), and February and March 2004 (period-II) toevaluate and characterize the instrument. The good correlation between absorption coefficients measure by the instrument and EC concentrations measured by thermal method was found (R²=0.961 at period-I and R²=0.797 at period-II). One-hour BC concentrations calculated based on the regressions rangedfrom 0.5 to 7.8μg/m³. The instrument was found to be easy to use and had sufficient sensitivity to beuseful in atmospheric monitoring.

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Cancer risk from diesel exhaust particle (DEP) was estimated using data collected at ambient and roadside air monitoring stations in Sapporo. DEP concentrations were calculated based on the three assumptions: i) 90% of ambient elemental carbon (EC) originate from DEP, ii) 40% of DEP consists of EC, and iii) Human exposed DEP concentration is 80% of ambient DEP concentration. The cancer risks from polycyclic aromatic hydrocarbons (PAHs) and nitro-polycyclic aromatic hydrocarbons (NPAHs) were compared to the cancer risk from DEP (1.3×10^-3 in summer and 1.5×10^-3 in winter). The sum of the cancer risks from five PAHs and three NPAHs (1.1×10^-7 in summer and 4.1×10^-7 in winter) was much less than that from DEP. The correlation between EC and available data (NOx and SPM) at the air monitoring station in Sapporo was examined. EC and NOx showed higher correlations (R²=0.583 (summer), 0.775 (winter)) than EC and SPM. DEP cancer risks were calculated for each air monitoring stations with the regression between EC and NOx. The risks for the ambient air monitoring stations and roadside air monitoring stations ranged from 8.4×10-4 to 1.5×10^-3 and 1.4×10^-3 to 2.5×10^-3, respectively.

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In this study, the performance of permeable walls that can achieve denitrification reaction by injecting H₂ gas was studied experimentally and theoretically. In laboratory-scale sandy aquifers, permeable walls were constructed with sand, gravels, and two other granules. Groundwater containing about 25mg-N/l of NO₃^- with some nutrient was fed continuously at various HRTs, and measurements of nitrate, nitrite, DO and pH were made over one year. Experimental results showed that all permeable walls could remove nitrate without accumulation of nitrite. However, the performance was different in four permeable walls. From this result, we found that the performance of permeable walls was influenced by the diameter of granule. We analyzed denitrification reaction rates using a mathematical model developed according to conventional mass balance and kinetic theory. The analysis showed that the denitrification performance of walls having relatively higher KLa value was lower than the model predictions. It was thought that these low performances resulted from plugging by microorganisms, as larger difference existed in higher biomass and higher dissolution rate conditions. Therefore granule in the permeable wall should be selected with consideration of volumetric mass transfer coefficient and plugging in walls.

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In order to remove phosphorus or control bulking, coagulants are sometimes added into the activated sludge process. Fe salts and Al salts are usually used as coagulant because they empirically have no influence on the removal efficiency. However, precise influences of coagulants on the respiratory activity of the activated sludge have not been clear yet. Firstly, the measurement method of dehydrogenase activity was discussed in this paper. Secondly, the influence of shock load of ferric chloride on the respiratory activity of the activated sludge was discussed from the batch experiments by measuring dehydrogenase activity and oxygen uptake rate.
The respiratory activity of the activated sludge decreased with ferric chloride addition. Decrease of pH, increase of Cl- concentration and increase of Fe concentration were suggested to decrease respiratory activity. The effect of increase of Cl^- and Fe concentration was found to be negligible at actual condition. However, respiratory activity was sensitive to the change of pH and it was decreased rapidly with decrease of pH. It is necessary to prevent the decrease of pH value by alkalinity addition in order to maintain the respiratory activity.

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As the United States and Europe is limiting the discharge of nitrate, this steps will be definitely be followed by Japan. Nitrogen and Phosphorous in wastewater has been recognized to cause problems such as etroprication and at present, there is no effective treatment method to treat such wastewater. A rotating meshed plates denitrification reactor was developed focusing on reducing liquid film diffusion layer that offers diffusional resistance from the bulk liquid to the biofilm surface.
Artificial wastewater and methanol as carbon source was used for this experiment and the following results were obtained: In experiment using wire rod with 3mm of diameter and 10cm long; 1) At 30rpm of rotating speed and 40 min of retention time, above 90% of denitrification rate has been achieved. 2) Compare to other denitrification reactor, achievement of a high denitrification rate when using the developed reactor for this study was because the diffusional layer is very thin. 3) In low rotating speed, a microorganisms was prove to block the holes of the meshed plates. In experiment using wire rod with 1mm of diameter and 10cm long; 4) At 15mg/L and 30mg/L concentration of nitrate nitrogen, denitrification ratio exceeding 90% in all rotating speed was obtained.5) At 60mg/L concentration of nitrate nitrogen, denitrification ratio in 120rpm of rotating speed was 90%. Moreover, denitrification ratio in 90rpm of rotating speed was 85%. 6) High ratio of denitrification was obtained by controlling dissolved oxygen level to be under 1mg/L.

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The removal of bacteria from rearing seawater of fish or using seawater in fishing port is important from the viewpoint of the reduction of infection risk and hygienics of public health. It is necessary to develop seawater purification technology for the improvement of hygienic conditions on the coastal environment. In this study, the removal of suspended bacteria Enterococcus faecalis from seawater by foam separation using several kinds of surface-active proteins as a chemical agent was examined. The removal efficiency of enterococcus was extremely low by foam separation using each protein without coagulation, because these surface-active materials did not function as a collector. When processing by foam separation with coagulation as a pretreatment, however, proteins such as milk casein and fish mucus showed the greatest capability of suspended bacteria. For treatment of seawater containing enterococcus (10⁷CFU/mL), the removal efficiency of counts number was over 99% with the small dosages of iron coagulant (FeCl₃) lmg-Fe/L and casein lmg/L. Foam separation using surface-active protein with coagulation process has a high potential as a new method for removing bacteria from seawater.

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A long term experiment was carried out to evaluate the process performance of sewage treatment system consisting of UASB pre-treatment and the “Fourth generation DHS” post-treatment unit. After the successful operation of second and third generation DHS reactors, the fourth generation DHS reactor was developed to overcome few shortcomings of its predecessors. This reactor was designed to further enhance the treatment efficiency and simplify the construction process in real scale, especially for application in developing countries Configuration of the reactor was modified to enhance the dissolution of air into the wastewater and to avert the possible clogging of the reactor especially during sudden washout from UASB reactor. The whole system was operated at a total HRT of 8h (UASB: 6h & DHS: 2h) for a period of over 600 days. The combined system was able to remove 96% of unfiltered BOD with only 9mg/L remaining in the final effluent. Likewise, F. coli were removed by 3.45 log with the final count of 10³ to 10⁴ MPN/100ml in the final effluent. Nutrient removal by the system was also satisfactory.

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Waterbased metal working fluids wastewater contains complex and highly concentrated organic matters, some of which are resistant to the biodegradation. Thermophilic contact oxdation process (TCOP) is suitable for the treatment of high strength wastewater, and the thermophilic bacteria are known to be capable of degrading persistent chemical substances. Therefore, in this study we tested the application of TCOP for waterbased metal working fluids wastewater and examined the influence of carrier water content on the treatment. Two kinds of compost for seeding almost equally supported the treatment of water-based metal working fluids wastewater by TCOP, and demonstrated TCOPs capacity for the treatment. The oil reduction ratio was higher for lower carrier water content in the early stage of the experiment, but after 28 days of operation, the oil reduction ratio for all carrier water content reached almost same level, above 70%. The reduction of each component was also measured by GC/MS. In the early stage, the reduction ratios of fatty acids were higher for higher water content, and those of alkenes were higher for lower water content. These results suggested that the relationship between water contents and reduction ratios have a commonality among the same group of chemical compounds.

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In the past several years our research group has been conducting R&D on a novel sewage treatment system applicable to developing countries by combination of an UASB anaerobic pretreatment unit and a DHS aerobic post-treatment unit. The DHS downflow hanging sponge process is our originally proposed concept, which employs poly-urethane sponge carrier as sludge supporting materials. In this study, the third-generation (G3-type) DHS reactor was installed at a municipal sewage treatment plant, and a longterm continuous experiment was conducted by feeding an actual sewage to the combined UASB/DHS system. The combined system achieved an excellent organic removal of over 90 % BOD, as well as nitrification of over 70 %, at HRT of bhr for UASB and 2hr for DHS units, respectively. Some key factors governing superior performance of organic removal and nitrification were clarified by the continuous flow experiment. Due to no requirement of external aeration input and withdrawal of excess sludge, our combined UASB/DHS system would be definitely attractive option as less-energy required sewage treatment process, especially for developing countries.

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Tokyo Metropolitan University constructed an advanced wastewater treatment facility when the university moved to its present location in 1991. To better serve the university, wastewater from experiments conducted by research laboratories was processed and recycled for flushwater. At the time, water quality guidelines for processed wastewater set by the university were more stringent than regulations established under the sewerage law. However, Volatile Organic Compounds (VOCs) were added to the sewerage law in 1994. As a result, it was necessary to revise the university's water quality guidelines and a directive was issued to collect VOCs directly from the research laboratories. Despite directly collecting VOCs, low levels of VOCs were still present in the wastewater and continued to flow into the wastewater treatment facility. Moreover, the past policy of annually replacing the activated carbon was not revised, creating a situation where VOC contaminant levels gradually rose until they exceeded the university's water quality guidelines.

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Denitrification and sulfate reduction of phenolic wastewater were examined using anaerobicoxic biological filter reactor. In the anaerobic reactor, sulfate reduction occurred. However phenol was not removed. In the anoxic reactor, heterotrophic denitrification and sulfur denitrification were occurred simultaneously. Phenol was utilized for denitrification. Utilization of cokes gas liquor wastewater by sulfate reduction and denitrificatin was examined using the biofilm in the reactor. Sulfate reduction occurred using ammonia stripped wastewater of the cokes gas liquor. However the phenol decomposition rates were very low. Heterotrophic denitrification occurred using the wastewater. Sulfur denitrification was not suppressed by the addition of the wastewater. Recovered sulfide from the gas liquor was utilized for sulfur denitrification.

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We have proposed a sewage treatment system by combining an anaerobic UASB and an aerobic biofilter reactor in order to diminish energy requirements and excess sludge production. A 17m³ pilot plant system was operated for over 300 days with continuous feeding of domestic raw sewage. The structure on microbial community of sludge samples taken from the aerobic biofilter reactor was analyzed by using clone libraries of 16S rRNA genes. Clone similar to Thiobacillus and Thiothrix was counted at 10 and 7, respectively, among 188 clones randomly selected from the libraries. Oligonucleotide probe Thio840 for fluorescence in situ hybridization (FISH) was newly designed for the specific target of Thiobacillus group. Approximately 7% of DAPI stained total cells in the biofilter sludgehybridized with the probe Thio840. This value was fairly agreed with frequency of the Thiobacillus clones to the libraries. Real-time PCR using SYBR green I was employed with BONE663cF-Thio840R primer set to determine the copy number of 16S rRNA gene originated from Thiobacillus. High concentration of sulfide at 30 mg-S/L in the influent strongly enhanced abundance of the gene of 10⁵ copies/ng levels in total DNA extracted from the aerobic biofilter sludge. As a result, the real-time PCR assay could be an appropriate tool to monitor Thiobacillus cells in sludge. However, the difference of amplification efficiency between PCR standards and target genes is a subject of discussion.

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The formation characteristic of TOBr during ozonation of sewage effluents was investigated. Though TOBr increased rapidly in the initial stage, it decreased slowly after CT value was over about 20mg min/L. It was seen that absorbance at UV₂₅₄ is a very available parameter for the estimation of TOBr formation. TOBr in a secondary effluent was decomposed at extremely initial duration of ozonation. The result was confirmed by the increase of bromide concentration. The degradation and mineralization of organic compounds arise during ozone/hydrogen peroxide process. The addition of hydrogen peroxide also controls the formation of hypobromous acid and the dissolved ozone concentration. So, the amounts of bromate ion and TOBr formed can be controlled at low level.

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Performance of a 3-dimensinal electrolytic process used for the treatment of dilute solutions wasinvestigated in two different oxidation modes, i. e. direct oxidation on the surface of electrode and indirect oxidationthrough the formation of oxidant. Decolorization of indigotrisulfonate in these oxidation was measured and represented as an equivalent oxidation performance by O₃. Experimental results demonstrated that electric current efficiency in the direct oxidation was 96% and energy consumption was significantly smaller than that of commercially-available ozonizer. However, the indirect oxidation process has poor performance in terms of electric current efficiency (1%) and energy consumption.It was considered that the direct oxidation process would be a feasible alternative of conventional oxidation process in water and wastewater treatment.

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Fibrous metal adsorbent having iminodiacetic acid was synthesized by radiation-induced grafting glycidyl methacrylate on nonwoven fabric and subsequent chemical treatment. The degree of grafting calculated by increasing weight after grafting reached 170% for reaction time of 2h at 40°C. The adsorption characteristics of ferric and manganese ions were evaluated by using the resulting adsorbent with 2. 1mmol/g-adsorbent function group of iminodiacetic acid. Each distribution coefficient of ferric and manganese ion deceased with increase of another coexist ion. Both ferric and manganese ions were completely removed by the adsorbent column at the space velocity of 1000h^-1. Adsorption capacities of both ions were reduced to 80% after 5 times reputation of adsorption and desorption.

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The simulation model to predict dissolved ozone concentration in a real ozone contactor was developed. The hydrodynamic behavior in the contactor was investigated by CFD (Computational Fluid Dynamics) technique before developing the reaction model. The ozone contactor was divided into small compartments and interaction between compartments was evaluated based on the result of CFD. Mass balance equations were established in each divided compartment with reaction terms. As state variables, organic compounds, odor compounds, bacteria groups, bromide ion, bromate ion as well as dissolved ozone were selected. Organic compounds were classified into only two groups in this model. The concentration of dissolved ozone was favorably evaluated and reasonable results were obtained for other items. From these, we conclude that dissolved ozone concentration as well as organic compounds, bacteria groups, bromate ion can be predicted in this model.

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Batch adsorption experiments were carried out using Hexagonal Mesoporous Silicates (HMSs) and dichloroacetic acid (DCAA) as a model Haloacetic acids (HAAs). The three types of grafted organic functional were n-octyldimethyl-, 3-aminopropyltriethoxy-, and 3-mercaptopropyl-groups. Titanium substituted HMS was also applied. Bi-functional grafted HMSs, which have both amino and mercapto functional groups, were synthesized to evaluate the effects of combined functional groups on adsorption capacities. Physical characteristic of synthesized HMSs didn't affect DCAA adsorption capacity; but grafted functional groups changed the surface charge of HMSs. Negatively charged DCAA was adsorbed only by positively charged HMS. A higher amount of surface amino-functional groups on HMS gave a higher positive surface charge and exhibited a higher adsorption capacity of DCAA. Combination of amino and mercapto-functional groups gave higher adsorption capacities in high DCAA concentration range despite lower surface charge than the amino-grafted HMS. Adsorption of DCAA decreased positive surface charge of HMSs due to neutralization of surface charge. At a low DCAA concentration range, adsorption capacities were strongly dependent on surface charge, and hence adsorbents with high positive charge densities, i. e. AM-HMS and A-HMS, had very high adsorption capacities for DCAA.

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Membrane filtration has been gaining popularity in the various field. However, membrane fouling is an obstacle for wider application of this technology. Especially, the control of irreversible membrane fouling, which can be defined as fouling requiring chemical reagents to be mitigated, is of importance. The aims of this study were (i) to investigate the degree of irreversible fouling caused by different organic matters and (ii) to characterize the faulants that caused irreversible fouling. In this study, four different organic matters (commercially available humic acid, organic matters isolated from two drinking water sources and a wastewater treatment effluent) and membranes (two microfiltration (ME) membranes and two ultrafiltration (UF) membranes) were used. It was observed that the permeate flux did not decline in the UF membranes while there was a large flux decline in the MF membranes. Especially, a rapid flux decline was observed with the polyvinylidene fluoride (PVDF) membrane. The extents of fouling in the MF membranes were strongly depended on both the types of organic matters and membrane materials. A series of chemical analyses such as fluorescence excitation-emission matrix (EEM), specific UV adsorbance (SUVA) and ion chromatography (IC) were applied to elucidate which fractions of organic matter caused the irreversible fouling. SUVA of faulants was significantly lower than was determined for the feed water. This implies that the faulants had hydrophilic features. The results with EEM and IC also confirmed that a variety of hydrophilic compounds such as polysaccharide or protein-like compounds contributed to the formation of the irreversible fouling observed in this study.

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This study examined the influence of operating conditions on membrane fouling in membrane bioreactors (MBRs) used for municipal wastewater treatment. Also, the mechanism of fouling evolution was investigated based on both pilot-scale and lab-scale experiments. Three pilot-scale MBRs were operated for about 100 daysat an existing municipal wastewater treatment facility. In the long-term operation, probably because aeration intensitywas enough to avoid formation of cake layer on the membrane surface, reversible fouling was not significant (i. e., irreversibletype of fouling dominated). The lab-scale experiments demonstrated that dissolved organic matter (DOM) accumulating in the reactors was likely to be responsible for the irreversible fouling. DOM loading on the membrane surface was found to influence the degree of total filtration resistance. It was revealed that changes in the composition of DOM (e. g., decrease in specific UV absorbance) in the reactors were also related to the irreversible fouling. Especially, dissolved sugar and dissolved protein contained in the mixed liquor played an important role in the development of the irreversible fouling.

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Chromosomal aberration test and the differentiation method between total organic chlorine (TOC1) and total organic bromine (TOBr) were employed to evaluate the contribution of brominated disinfection by-products to the toxicity of chlorinated water in the presence of bromide ion. From the experiments using a high concentration humic acid solution, the toxicity of TOBr was found to be 4. 8 times higher than that of TOC1 on TOX basis, and the contribution of TOBr to activity inducing chromosomal aberrations reached 50% when the bromide-to-TOC ratio was 0.1 mg Br/mg C. Same experiments were conducted with Lake Biwa water. In this case, it was found that the toxicity of TOBr was foundto be approximately 10 times higher than that of TOC1 on TOX basis, and the contribution of TOBr to activity inducing chromosomal aberrations reached 30% even at the ambient bromide concentration (38.2μg/L).

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The effect of nitrite as electron acceptor was examined in a sequence batch reactor (SBR) for biological phosphorus removal. Experiments were carried out using a lab-scale SBR treatinga municipal wastewater. The reactor had anaerobic phase followed by anoxic phase. To make anoxic phase, nitrate and nitrite were added. The phosphate uptake rate under both aerobic and anoxic conditions were measured by batch tests. Moreover, microbial communities were also analyzed using polymerase chain reaction and denaturing gradient gel electrophoresis (PCR-DGGE) assay. The following results were obtained from the batch test: 1) the sludge cultivated with nitrite could readily utilize oxygen as well as nitrite, 2) it could utilize nitrate after one hour adaptation, and 3) it could utilize nitrite to take up phosphate with same efficiency as nitrate or 40% lower than oxygen. Furthermore, the DGGE image showed that a fewbands appeared or disappeared when the operational condition changed. One possibility is that the changing bands were derived from denitrifying polyphosphate accumulating organisms (PAOs) either with nitrate or nitrite. Further research on these bands would clarify the behavior of the microbial communityof PAOs.

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Due to a great progress in molecular techniques in microbial community analysis, microbes in enhanced biological phosphorus removal (EBPR) activated sludge are now intensively investigated. Several new candidates for polyphosphate accumulating organisms (PAOs) are now discovered or proposed. In this research, laboratory scale reactors were operated using glucose or aspartate as a sole carbon source and the microbial community was investigated using PCR-DGGE, cloning and FISH. In the aspartate fed reactor, Dechloromonas related bacteria which accumulated polyhydroxyalkanoate (PHA) but not polyphosphate (behaving like glycogen accumulating organisms (GAOs)) was found to exist significantly even when phosphate was well removed. On the other hand, in the glucose fed reactor, three Actinobacteria related genotypes were found. Although these genotypes were closely related to each other, one existed significantly when phosphate was removed well, and the others were found when the phosphorus removal activity was deteriorated. In both reactors, Rhodocyclus related PAO candidate was found at a certain level (about 20% of eubacteria) when the phosphorus was removed well, but the DGGE band corresponding to the bacteria didn't correspond to the profile of phosphorus removal activity.In this way, the complexity of microbial communities in EBPR activated sludge was shown.

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A new method was developed to quantify Cryptosporidium in water. Quenching Probe PCR (QProbe-PCR) technique could successfully amplify approximately 1280bp of Cryptosporidium 18S rDNA from a sample with as low as 60 [oocysts/tube] of Cryptosporidium parvum bovine genotype. QProbe-PCR showed high accuracy and high sensitivity compared to Real Time PCR with TaqMan probe.
QProbe-PCRh as an advantaget hat the PCR products can be applied for molecular characterization. Arestriction fragment length polymorphism (RFLP) technique was used to distinguish Cryptosporidium species and genotypes. Five species (C. parvum bovine genotype, C. parvum human genotype, C. meleagridis, C. felis and C. muris) could be distinguished by the RFLP with restriction enzymes Ssp I, Vsp I and Sty I. The Sty I successfully differentiated C. muris calf genotype (also known as C. andersoni) and C. muris mouse genotype. Database-based analysis revealed that 8 species out of 10 could be distinguished by RFLP with these three restriction enzymes.
QProbe-PCR-RFLP techniques can provide information on the genotype as well as the quantity of Cryptosporidium from the same sample. This technique can be a useful tool for waterborne risk assessment of Cryptosporidiosis.

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We investigated the population dynamics of nitrifying bacteria in autotrophic nitrifying biofilms by using Real-Time PCR and fluorescent in situ hybridization (FISH). Primers and TaqMan probe specific to genus Nitrospira including uncultured Nitrospira sp. in the biofilms were newly designed and applied to the biofilms. The populations of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) determined by Real-Time PCR during steady-state condition were 1.2×10⁸cells/cm² and 3.5×10⁸cells/cm², respectively. The population dynamics of nitrifying bacteria corresponded with the reactor performance and the development of nitrifying bacteria in the biofilms determined by FISH. Real-Time PCR revealed that specific growth rates of uncultured Nitrospira sp. were 0.021h^-1 in the suspended enrichment culture and 0.014h^-1 in the biofilms. Average specific growth rates of both nitrifying bacteria during the steady-state condition in the biofilms were significantly lower than that during the log phase, might suggest that metabolic pathway of nitrifying bacteria in the biofilms was different in the log and stationary phase. We speculated that Real-Time PCR was powerful and suitable technique for understanding of microbial population dynamics in the complex microbial communities.

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Outbreaks of waterborne infectious diseases caused by pathogenic viruses have been frequently documented over the world. Pathogenic viruses can survive for a long period in water environment, but there has been a difficulty in removing or inactivating viruses in conventional water and wastewater treatment systems. A new technology for the virus removal from water needs to be developed. In our previous study, virus-binding proteins (VBPs) demonstrating the ability to strongly bind Poliovirus type 1 (PV1) were recovered from a bacterial culture derived from activated sludge. It was expected that the isolated VBPs would be useful as viral adsorbents under the conditions of water and wastewater treatments. In order to develop new technology for virus removal, it is important to isolate not only VBPs for PV1 but also VBPs for other important pathogenic viruses in water. In this study, Adenovirus-Binding Proteins (ADVBPs) for Adenoviruses type 3 (AD3) and type 40/41 (AD40/41) were newly isolated from activated sludge culture with the affinity chromatography technique. Three distinct peaks were sequentially obtained in each affinity chromatographic profile of ADVBPs for AD3 and AD40/41, respectively. The isolated ADVBP in the first peak include a number of proteins, and their molecular weights were widely distributed. ELISA revealed that the ability of binding Adenoviral particle of ADVBP in the second and third peaks were stronger than those in the first peak in the affinit chromatographic profile. It is speculated that the isolated ADVBPs can be useful as specific adsorbents for Adenoviruses in several fields including virus removal, concentration and detection.

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Seasonal overgrowth of cyanobacteria such as Microcystis aeruginosa (M. aeruginosa) is one of serious problems in semi-closed water area including reservoirs. It is known that algogenic organic matters (AOMs) bring about the inhibition of coagulation on the flocculation process in drinking water treatment systems. Our previous studies have shown that some kinds of protein in AOMs are responsible for the inhibition of coagulation, although the mechanisms of the inhibitoiy effects of algal proteins remain unclear. In order to reveal the inhibitory mechanism of algal proteins, it is necessary to identify the algal proteins closely related to the inhibition of coagulation. In this study, phage display using the genome of M. aeruginosa was constructed to extract algal proteins that exhibit the inhibitory effect on the coagulation. M. eruginosa cells on steady growth phase were collected, and genomic DNA of M. aeruginosa cells was extracted. Thean, extracted algal DNA was digested by the restriction enzyme Sau3AI. The phagemid vecter named pSKAN8-EWQ was newly created, in which BamHI recognition site was included as a single site for the restriction enzyme. Digested genomic DNA of M. aeruginosa was ligated with pSKAN8-EWQ, and the ligated phagemid vector was used to transform the competent cells of E. coli JM109. The cocktail of phages displaying algal proteins was obtained by introducing the helperphage (VCSM13 Interference-Resistant Helper Phage) into the transformed E. coli cells. It was confirmed that obtained phages are able to infect E. coli. JM109, and transform E. coli. cells into the ampicilin-resistant strain. This thing indicated that the phage display system for algal proteins was successfully constructed. The phage display established in this study will definitely contribute to identifying the inhibitory algal proteins on the coagulation, and revealing the inhibitoiy mechanism in the further study.

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The biomass fixed inside the porous medium, for example sponge cube, has the biofilm characteristics from the results of kinetic experiment. In this investigation, the biomass fixed inside the porous medium is nitrifying bacterium cultivated in autotrophic medium. Then characteristics of biomass fixed inside the porous medium was investigated by using Oxygen Utilization Rate (OUR). Furthermore the inner structure of nitrifying bacteria in biofilm fixed inside porous medium and biofilm thickness were investigated by Fluorescent In Situ Hybridization (FISH). Consequently The biofilm thickness by OUR was different from that by FISH.

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Zostera bed is an important habitat for fish juveniles and other coastal living organisms. Thus, Zostera bed creation and/or remediation projects are operated in many places in Japan. When Zostera bed is created by planting seed, the environmental conditions need to be clearly understood for the region which may serve as Zostera bed. The purpose of this research is to determine the region which may serve as Zostera bed in Yamaguchi bay where Zostera bed remediation project is going on. By using bed conditions such as COD, IL, particle size, and the disturbance strength caused by wave and current, a HSC model was constructed to evaluate the Zostera bed habitat condition. Based on the bed condition HSCs, Zostera habitat might be spreading toward the north area of the present Zostera bed. By adding the disturbance HSCs, the north area of the present Zostera bed might be inappropriate, thus Zostera bed is limited in the present region.

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The river Akagawa has been receiving the effluent from an acid mine drainage treatment plant. Intensive investigationsw ere conducted to study the effect of the effluent on the growth of attached algae in the river Akagawa. From the results obtained by multivariate analyses of the data based on these intensive investigations, it was suggested that the metals in the sediments had an adverse effect on the growth of attached algae, and especially, Al in the sediments had the most adverse one. We carried out the investigationin the river Akagawa focusing on the Al forms classified into monomeric fraction (Al-a) and polymeric one (Al-b) by the ferrron method. The result showed that the middle reaches had a high concentration of Al-b containing phytotoxic Al13 polycation compared with the upper and lower reaches. In batch culture experiments of attached algae, it was found that an addition of Al to the culture accelerated the decay of algae severely in the pH range from 4 to 5. From these results, there is a possibility that the low content of Chlorophyll a in the sediment observed in the middle reaches of the river Akagawa is caused by Al-b formed by hydrolysis

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Humic substances (HS) derived from terristrial area play important roles to supply essential minerals for the growth of aquatic organisms in estuaries. Therefore, the watershed management focusing on the transportation of essential minerals from terrestrial area to estuaries is needed for the conservation of estuarine ecosystem. Although it is said that a part of HS coagulates in estuaries with the increase of salinity, its mechanism has not been well-known. In this study, the coagulation model for humic substances in estuaries was developed on the basis of DLVO theory and hydrophobolic interaction which caused a strong attractive force between HS. This attractive force was estimated with hydrophobic index (E254/TOC) of HS and its molecular weight detected by gel chromatography analysis with 254nm spectrophotometer. The developed model could explainthe coagulation mechanism of humic acid according to the decrease of surface potential in estuarine condition. The result of simulation using this model showed that humic acid with intermediate molecular weight around 20k Da easily coagulated at the high salt concentration in estuaries.

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Humic iron complex is one of the most essential minerals for the growth of aquatic organisms in estuaries. However, the behavior of humic iron complex has not been known so well in estuaries where salinity widely changes. In this study, the effect of salinity on the behavior of humic iron complex was investigated with the Dando humic and fulvic acids. The increase of salinity, especially divalent cations such as magnesium and calcium ions, enhanced the coagulation of humic substances (HS). When the salt concentration increased from 0 to 30g/L, 81% of dissolved humic acid (HA) and 18% of dissolvedfulvic acid (FA) transformed to the particulate (>0.45μm) due to the coagulation. Gel chromatography analysis with UV spectrometer (254nm) revealed that high molecular weight and hydrophobic fractions of humic substances were important factors relevant to the coagulation. The increase of salinity also enhanced the dissociation of iron from HA and FA. With the increase of salt concentration from 0 to 30g/L, 98% and 88% of iron dissociated from HA and FA, respectively. It was expected that amino and sulfo groups on the surface of HA and FA which possess a high affinity with iron contributed to the subsistence of dissolved iron in estuaries.

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Lake Shinji is the blackish lake, located in the east part of Shimane Prefecture. A large amount death of Gizzard shad (Konosirusp unctatus) occurredi n 1996 in Lake Shinji. Sincet hen, a strangep henomenon such as the death is making an appearance every year. This large amount death is a very serious problem for the fishery and the water quality environment in Lake Shinji.
This research, try to find causes of the death, describes a forecasting model that analyze the relation between the water quality and the large amount death of Gizzard shad. We considered about the hypothesis of the factor of Gizzard shad's death. Thinking about the hypothesis, we paid attention to decreased physical strength of Gizzard shad by the spawning. Additionally, we paid attention to Gizzard shad going up the river from Lake Nakaumi to Lake Shinji to spawn. And we will try to establish the model for forecasting the large amount of death based on the hypothesis.

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Abnormal growth of phytoplankton (water bloom) causes the impediments of water utilization. In Miharu Dam Reservoir, the water bloom did not grow in 2001, but it grew in 2002. Seasonal changes of the phytoplankton growth, water quality and weather condition in Miharu Dam Reservoir were investigated during 2001-2002. Growth characteristics of the phytoplankton in Miharu Dam Reservoir are examined from differences in 2001 and 2002.
Major results obtained from this study are;
(1) Conditions of the water temperature, daylight hours, and phosphorus were suitable for growth of the phytoplankton in 2002 rather than 2001.
(2) The difference of the phosphorus concentration of 2001 and 2002 is remarkable, and the difference is considered to have induced the difference of the phytoplankton growth.
(3) The phosphorus concentration of Miharu Dam Reservoir receives influence by the amount of
the inflow phosphorus loads, and the amount of inflow phosphorus loads is restricted to the variation of flows accompanied by rain. Thus, it is considered that variation of the inflow phosphorus load accompanied by rain is the limiting factor of the phytoplankton in Miharu Dam Reservoir.

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A new toxicity test using concentrated river water and Medaka larva had been proposed by Urano et al. The purpose of this research is to clarify the relationship between this toxicity test and aquatic habitat conditions in rivers. Median Effect Time (ET₅₀) and Median Lethal Time (LT₅₀) are employed as indices of toxicity ASPT (Average score per taxon) for benthic animals and IBI (Index of Biotic Integrity) for fish are applied as indices of aquatic habitat conditions. Although ASPT for benthic animals shows high correlation with toxicity, IBI for fish shows poor correlation with it. IBI consists of six elements, namely species richness, indicator species, immigrant species, fish condition, trophic composition and fish abundance. From multiple regression analysis of the IBI elements against the toxicity the percentage of tolerant species, which is one of the IBI items, is verified having close relation with toxicity. From these analyses, it is revealed that two hours or shorter of LT50 and ET50 might cause deterioration of aquatic habitat.

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Algal bloom is one of the major environmental problems in closed water bodies. Reduced water currents and high inflow of nutrients to the water bodies are the main reasons behind this problem. Although many researches have been done, effective techniques to minimize the problem are still lacking. The objective of this investigation was to evaluate the effectiveness of mud gels and silver-contained ceramics in growth control of algal bloom. The experimental results showed that use of mud gels and silver-containing ceramics were very effective in controlling algal growth. Bacillus Megaterium was primarily affected while using mud gels. Photo catalysis and silver ions were mainly responsible for algal growth control while using silver-contained ceramics. Effectiveness of this technique increased when mud gels and silver-contained ceramics were used together probably due to synergic effects. This technique of controlling algal bloom can be more effective compared to other available methods.

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In this study we present a new ecosystem model which has a compartment of a macrobenthos Muscalista senhousia which was mainly dominated in sediment at shallow water area of Hakata Bay. The results of water qualities estimated by this newly developed model were more precise than that estimated by a model which does not have the macrobenthos compartment. This result shows that macrobenthos in the sediment has a great effect on estimating the water concentrations and forecasting the behavior of oxygen-deficient water body.

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Batch experiments using sediment mud liquors spiked with 17β-estradiol (E2) were performed at 5ºC and 20ºC under well-controlled aerobic and anaerobic conditions. The sediment mud liquors were prepared from the sliced surface, middle and bottom layers of sediment cores collected at a pre-reservoir of the Miharu Dam, respectively. By measuring the concentration profiles of E2 and its major biotransformation compound, estrone (E1), the great dependency of E2's behavior upon the vertical position of the sediment and temperature was clearly demonstrated; and the differences in the time course of E1 under both the aerobic and anaerobic conditions were clearly revealed. Besides, by assuming a first-order rate reaction, the disappearance rate (k) of E2 under the aerobic condition was estimated to vary in the range of 0.002-0.12 hr^-1/(g-dry/l), while that under the anaerobic condition in the range of 0.002-0.062 hr^-1/(g-dry/l). Larger k values were found to be associated with the surface sediment layers operated under the aerobic condition and with the higher temperature of 20ºC. The addition of ammonia and nitrate to runs carried out under the aerobic and the anaerobic conditions, respectively, seemed to be responsible for promoted dissipation of E2 from solutions. Furthermore, through combined analysis of the behavior of E2 and E1 in both the liquid and the solid phases of the mud liquors, possible biotransformation pathways of E2 under both aerobic and anaerobic conditions were proposed.

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Utilization of municipal solid waste (MSW) incineration residue as construction material is discussed due to the lack of the capacity of MSW landfill site. And, it is required that heavy metal components such as Pb in bottom ash has not to leach out. In this study, the immobilization of Pb by carbonation process was examined as a pretreatment for the stabilization of heavy metal components in bottom ash. It was confirmed that Pb concentration of leachate from bottom ash greatly decreased by CO₂ gas passing through the bottom ash packed in column. Especially, water content range from 10 to 20% in bottom ash was suitable for the absorption of CO₂ gas and Pb immobilization. Changes of alkalinity and EC that affect immobilization of Pb by CO₂ gas were observed. Increases of calcite (CaCO₃), which is able to adsorb Pb were also confirmed with X-ray diffraction analyses. Mechanism of immobilization of Pb was examined by using the chemical equilibrium computation of various Pb spicies.

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This paper focuses on the characteristics of settlement and flocculation of incineration residue in sea area landfill site. The column was filled with seawater and bottom ash which was put into the column. The seawater for analyses was vertically and intermittently sampled, while sedimentation situation of particlesin the seawater was observed. Bottom ash that threw in the seawater was separated into coarse-grained and fme-grained waste; and they formed two layers. Bottom layer was coarse-grained layer, and upper layer was mud layer. Fine-particle waste contains twice as many components of organic as coarse-grained waste. Furthermore, coefficientof permeability of mud layer was order of 10-6cm/s. It is possible that mud layer prevented diffusion of the pollution component from coarse-grained layer to the seawater. The pollution component in landfill will be decreased, if there are flocs in the settlement. This means that by the promotion of flocculation and its active clearing, and thatthe stabilization of a sea area landfill site is promoted.

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