More than 80% of johkasous do not have the nitrogen removal capabilities. Sulfur and limestone autotrophic denitrification (SLAD) methods were used as alternative nitrogen removal methods. These methods were applied to johkasous without nitrogen removal function and those with low nitrogen removal efficiencies. Johkasou-treated water was passed through the model device of the waterway type, which was filled with a base material. The average nitrogen removal rate was approximately 80% in summer. However, the average nitrogen removal rate was low from autumn to winter. Removal efficiency could be improved by increasing the retention time (decreasing the flow rate and increasing amount of contact with the base material). PCR-DGGE results showed that the dominant bacterial species in the suspended solids (SS) attached to the base material was of the genus Sulfurimonas. During the experimental period, abundant SS were attached to the base material. Therefore, periodic maintenance of the base material was required.

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 To apply the Japanese johkasou to overseas countries, it is necessary to discover the design method that allows the redesign of the Japanese johkasou to meet various operational conditions. In this study, focusing on the differences in performance evaluation method between Japan and EU – wastewater volume and pollutant loads, an EU-oriented facility was designed with equal BOD volumetric load to the prototypical Japanese model, and was installed and experimented in the EU region. Meanwhile, the Japanese model was tested in Japan. The test results were then comparatively analyzed. As a result, BOD and SS in effluent in the EU test were at the same level with the Japanese model, and no influence of short-term inflow load fluctuations on effluent quality was observed. Moreover, the analysis of the influence of water temperature on treatment performance shows that the design method using BOD volumetric load and considering the influence of water temperature on the nitrification rate is effective for adaption of johkasou to overseas countries. Furthermore, it is suggested that keeping water temperature in the facility over 13 °C is important for constant removal of nitrogen and BOD.

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 Targeting to small municipalities where may not be developed large scale sewerage system for long term in the Philippines, appropriate community size for domestic wastewater treatment utilizing Johkasou was studied in view point of construction cost. 11 cases were set at varying in size of residencial area, housing density, and aspect ratio on residencial area. By generating random number, 50 samples for each case, 550 samples in total were made, and design of sewer pipe network was conducted. The total length of sewer pipe network depended on not only housing density but also size of residential area and aspect ratio of the residencial area. On establishing communities for small scale wastewater treatment facilities applying Johkasou, in case size of residential areas are set at 0.25, 0.5 and 1.0 hectar, minimum numbers of housing density were set at 18, 15 and 11 households per hector respectively through sensitivity analysis, which can be realized with lower cost comparing to individual Johkaso installing to each household.

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 Towards the realization of "resource recovery type sewage treatment plant" as a water, materials and energy circulation base in the watershed, this study is conducted on the core sewage treatment plant (STP) of K city which is one of the largest scales in Japan. There were investigated digestion gas power generations as energy recovery, phosphorus recovery as resource recovery, advanced treatment as water use, and calculated the potential (recoverability). In energy recovery, the amount of generated electricity will increase to 51,760 kWh/day when receiving sludge from three STPs and solubilizing excess sludge, and the self-sufficiency rate will be expected to be 28.8 %.In the case of phosphorus recovery, when receiving sludge from three STPs and solubilizing excess sludge, the amount recovered from the dehydrated filtrate will be about 800 kg /day, and overall the phosphorus recovery rate will be 50 %. In the case of advanced treatment, the quality of the discharged water is improved in the entire STP. Not only the water quality but also the electric power consumption unit tends to decrease. When evaluating water, materials and energy recovery function as the environmental performance of the STP as an indicator of water eco-efficiency, 4 kg/kWh will be expected by achieving resource recovery type STP with digestion gas generation, phosphorus recovery and advanced treatment, from current situation 2.68 kg/kWh.

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 Experimental study was carried out in Lake Abashiri where is brackish lake with double-layered formation of freshwater and saltwater. In order to reduce anearobic salt water layer, we installed the gas dissolving apparatus (WEP) in the actual waters. And we obserbed water quality change by the oxygenation. As a result of oxygen supply for two months, dissolved oxygen was increased around the equipment, but influenced area was very small. It was confirmed that oxygen consumption by hydrogen sulfide was large then dissolved oxygen could not be detected. On the other hand, solid sulfur was generated by oxygen supply and then the turbidity was rised. Therefore, when the turbidity is assumed to be a tracer, it is confirmed that the oxygen supply effect expanded to about 120 m square on the bottom water flow. From the results of the water quality analysis, it was cleared that the reduction of hydrogen sulfide with oxygen supply of WEP further phosphorus and nitrogen were reduced. It suggested that detoxification of specific elevation layer is possible in the anearobic brackish lake additionaly nutrient salt is possible to reduce.

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 Some previous studies showed strong correlation between the organic content and water content of bottom sediments. However, few studies compared sediment data of multiple water areas and the relationship between the organic content and water content is only empirical. In this study, we analyzed bottom sediment data of several eutrophic coastal and brackish water areas and examined the relationship between them. As a result of the analysis, the relationship between TOC and water content in multiple water areas showed statistically similar correlation, except a few samples collected nearby river mouths. In addition, we made laboratory experiments with sediment samples whose organic matter were previously decomposed by hydrogen peroxide solution. The treated samples were redeposited gravitationally in a test tube and measured the water content of the deposited sediment. The result of experiments revealed that the water content of decomposed samples was significally lower than that of the original samples. These results indicates that organic matter originated from the primary production strongly controls the sedimentation process and thus affects the water content of the surface bottom sediments.

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 We propose a new method to simultaneously identify limiting factors for productions of multiple primary producer types in costal planktonic communities. This method combines fatty acid composition analysis with conventional algal growth potential tests in which various combinations of nutrient and metal species are added to coastal waters. For seawater collected from Shizugawa bay in September 2017, it was shown that the production of POC and chlorophyll a were primarily limited by nitrogen. The fatty acid composition analysis indicated that nitrogen addition markedly increased particle productions especially by bacteria or cyanobacteria. Meanwhile, the productions of fatty acid markers of diatoms, dinoflagellates and green algae remarkably increased by phosphorus addition, so production of those algal groups seems to be limited by phosphorus rather than nitrogen. Overall, our method has great potential to bring useful knowledge to help to predict responses of inner bay primary producers to changes in material compositions loaded from watersheds. Concerning the preservability of the marker fatty acid composition, further study is necessary.

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 Hypoxia in bottom water has been a major environmental problem in inner bays. To conserve coastal marine ecosystems, it is necessary to enhance understanding of effects of human activities including aquacultures on material dynamics linking with hypoxia formation. To understand effects of oyster farming on the dynamics of particulate organic matter (POM) and potentials formation of the hypoxia in bottom water, biochemical compositions and oxygen consumption rate of POM were examined in Shizugawa Bay of northeastern Japan. We analyzed POM for fatty acid markers to evaluate the relative contributions of POM with various biological origins. The effects of oyster farms were evaluated by comparing compositions of POM between inside and outside oyster farms. Our results showed that in summer the oxygen consumption rate of POM was greater compared with the other seasons and also positively related to the content of algal fatty acid markers. POM derived from algal blooms in spring to summer seasons may be attributable to the higher oxygen consumption rates. Inside the oyster farms, the proportion of algal fatty acid markers was generally lower, and the degradability of suspended POM was considered to be lower. The relationship between bacterial fatty acid markers and oxygen consumption was also weaker in the farms. The present study supports a potential use of fatty acid markers for estimating the major origins of POM contribute to the oxygen consumption.

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 Microalgae cultivation systems are important for utilizing sewage resources or producing biomass in a wastewater treatment plant (WWTP). The aim of our study was to establish an naturally generating microalgae cultivation system that utilizes several sewage resources in a WWTP. To this end, we investigated the utilization of sewage sludge, which is a sewage resource, in relation to microalgae cultivation. Excess sludge was diluted with raw wastewater and was used as a substrate for microalgae cultivation.
 Results showed that when substrate added dilutied sludge, microalgae biomass (SS and chlorophyll a) was increased, with a higher SS concentration. Furthermore, approximately 80% - 90% of COD (Chemical Oxygen Demand) in raw wastewater were removed because of the microalgae cultivation utilizing sewage sludge. In addition, additional amounts of CO₂ for microalgae cultivation can be reduced by the presence of bacteria, and the total amount of heat value of cultured microalgae can be increased by the addition of sewage sludge.
 In this study, it was shown that a microalgae cultivation system utilizing sewage sludge could produce more microalgae biomass and had a higher efficiency than that without using sewage sludge in WWTPs.

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 Loading of Mg and P into anaerobic digester from surplus activated sludge was 3 and 4 times greater than that from raw sludge, which indicates that surplus activated sludge would be a target in reducing Mg loading into anaerobic digester. Anaerobic release of Mg, P and K from the surplus activated sludge was accelerated by the addition of thickened raw sludge and these elements in the centrifugal separate liquid was concentrated using a prototype of electrodialyzer. Furthermore, anaerobic cultivation of surplus activated sludge with thickened raw sludge in the existing storage tank during 6 hours decreased the contents of Mg, P and K in the thickened surplus activated sludge by 40 - 50%. These findings suggest that accelerated anaerobic release of the elements from surplus activated sludge could provide an opportunity to recover Mg, K and P from the separate liquid discharged from the subsequent mechanical thickener and decrease the Mg loading into the digester for inhibiting a blockage of sludge transport pipes due to struvite.

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 Improvement methods of polysaccharide degradation and lactate yield in thermophilic _L-lactic acid fermentation were evaluated with kitchen garbage and high-yielding rice as materials for biodegradable plastics. Based on the batch experiments, it was cleared that low decomposition ratio of total sugar and lactate yield were obtained from kitchen garbage without banana skin, comparing to those from kitchen garbage. It was found that pretreatment of starch by heat from 55°C to 100°C had little influence on polysaccharide degradation and lactate yield of kitchen garbage. Addition of nitrogenous organic compounds i.e. yeast extract and polypeptone were investigated in order to evaluate influences of organic nitrogen concentrations on decomposition ratio of total sugar and lactate yield with high-yielding rice. Compared to the case without addition of nitrogenous organic compounds, higher polysaccharide decomposition ratio and lactate yield can be obtained, and it is determined that addition of both 0.25 g/L of yeast extract and 0.25 g/L of polypeptone is desirable for thermophilic _L-lactic acid fermentation with high-yielding rice. Meanwhile, little influences of addition of minerals on the fermentation were found. In addition, it was suggested that the suitable operationg condition for thermophilic L-lactic acid fermentation with high-yielding rice was that of pH 5.5 and 55°C.

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 In this study, we carried out the button mushroom cultivation tests on media covered with peat moss which induces primordia in order to improve the mushroom yield. By the peat moss's properties of high density and low water absorption rate, the yield increased 1.5-1.7 times compared to the past test results, which achieved the target value (150-250 kg/1000kg compost) for management of button mushroom production. Since the button mushroom requires a relatively long cultivation period, it greatly influences on the medium composition. It is presumed that composition of fruit bodies will change depending on the difference of medium composition. Therefore, the effect of the differences in harvest time on the composition of fruit bodies was investigated. The composition of fruit bodies varied due to the occurring time. We found that the amount of protein increased in the fruit bodies occurred later. The mushroom waste beds were used for the cultivation of leaf vegetables by the general application method of compost. The growth of Komatsuna (Japanese mustard spinach) somewhat diminished, but the growth of Chingensai (Bok choy) were equal or higher compared to the control. These results led us to conclude that the waste bed were usable for agricultural purpose.

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 It is important to consider wide-area water supply and asset management in an integrated manner to realize sustainable water supply systems. However, there is no established planning method for long-term operation and renewal of wide-area water supply systems which is adapted to temporal change of constraints such as water source availability, future water demand and facility aging. In this study, mathematical optimization was applied to make a long-term planning scenario of operation and renewal of wide-area water supply systems. And then a novel planning method was developed which can make an optimal scenario with the smallest cost under the necessary facility renewal condition.
 As a case study, the developed method was applied to make a plan for next 50 years in a virtual water supply system composed of 8 water utilities, imagining the eastern area of Gunma prefecture. Constraints including topography, locations of purification plants, layout of main pipes, and temporal changes of water resource availability and water demand were given to the planning method. In the case of networking and consolidation of water purification plants among water utilities in a wide area, the average cost throughout the entire planning period was reduced by 10.4% compared to individual utility-based planning without networking. In addition, expenses for facility aging measures were reduced by 8.9% in the case of wide-area water supply system when shortening the service life time of water purification plant from 90 years to 70 years. It was shown that more economic operation and renewal can be achieved by wide-area water supply systems with measures for facility aging compared to individual utility-based planning without networking.

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 Since the number of aged water pipes in our country has been gradually increasing, we have to develope evaluation methods for the degree of decrepitude in the pipes. Cast iron and ductile iron pipes comprise 58 percent of the water supply pipes in Japan. Corrosion pit depth was known as a symptom of decrepitude in the pipes. However, the previously proposed method for corrosion pit depth prediction was not able to show probability distribution of corrosion pit depth, and it does not utilize zero corrosion data (ca. 16 % in the whole data). Therefore, we aimed to show statistical distribution of corrosion pit depth by applying a bootstrap method to the 5589 pipe corrosion data that have been collected for ca. 50 years.
 Firstly, we classified the soil environments based on the difference in pipe corrosion rates at a significance level of 5 %. As a result, the soil envirouments were grouped into four by the soil types and the soil resistivity. Secondly, the statistical distribution of corrosion pit depth as a function of buried years for each of the four classifications was constructed using a bootstrap method, which is a non-parametric statistical method that can make use of zero-corrosion data. By this way, the probability distributions of corrosion pit depths and the years for the pits to reach the pipe wall thickness were estimated for sand over 45 years, silt 40 years, and clay 30 years. Finally, even in the same soil environments, the corrosibity was found to be influenced by the distance from marine clay by statistical analysis. As it was found that the soil environments in the vicinity of marine clay was more corrosive than those away from marine clay, it is recommended to investigate the presence marine clay within a ca. 500 m periphery.

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 To achieve universal access to safely managed drinking water as stipulated in Sustainable Development Goals (SDGs), it is necessary to secure the financial resources and to promote effectiveness of the investment. This study aimed to estimate the socio-economic factors to affect the progress of access to at least basic drinking water services and effectiveness of the ODA in Millennium Development Goals (MDGs) era. Per capita Gross National Products (GDP) and Human Development Index (HDI) was associated with the prevalence rate of access to at least basic water services while the other factors as ODA may have significant role to determine the progress of the access. Average capital investment cost (as capital expenditure, CAPEX) was estimated to be 365 USD per capita (148 to 931 in 95% confidence interval) as a population weighed mean value for 17 low to middle income countries. Necessary capital investment to achieve universal basic access by 2030, based on the capital investment cost per capita, was estimated to be 5.46 billion USD/year, implying that further investment from both ODA and other financial resources are necessary.

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 This study aims to evaluate a feasibility of community based water management system(CBWMS), as one of solution against infrastructure in population decreasing area. According to field results, current CBWMS are performing low cost management compare to municible water supply, on the basis of (1) maintenance by community, (2) users' and managers' concensus and high acceptability for temporal incombinient such as water cut-off, (3) works relating to management are manageable in their subsistence activities. On the other hand, current CBWMS do not have sufficient system about (4)risk management design and (5) asset data management. Thus, future CBWMS needs easy and simple technology package for community based management, and also needs support system from local and central government and water specialists.

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 Microcystis aeruginosa produces microcystin that is one of the hepatotoxin to human. Recent studies have shown that oxidative stress causes MCs production in the cellular processes. In addition, it has been indicated that iron limitation induces production of reactive oxygen species and associated oxidative stress in cyanobacterial cell. Therefore, this study aimed to elucidate the relationship among iron-stress induced oxidative stress and MCs production. Consequently, MCs content (per cell) increased under the intermediate iron availability (total dissolved iron concentration of 100 nM), where oxidative stress was also determined to be high. Moreover, overall MCs production rate showed the lowest value in the intermediate iron stress (i.e., total dissolved iron concentration of 100 nM), as the overall MCs production is also related to the cellular growth rate.

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 DNA analysis was conducted on the dominant species of microalgal culture under the LEDs irradiating condition. The results showed that diatoms and dinoflagellates were detected when the light source was only sunlight, whereas sunlight + LED (blue+red) condition showed that the proportion of eukaryotic algae increased dramatically, and green algae and diatoms, crypto algae dominated. Under each condition irradiated with the blue or red LED, all the clones under the red LED are closely related to the Synechococcus species. Under the blue LED, the diatoms (closely related species such as Chaetoceros genus) were dominated. These results were suggested that red LEDs promote dominance of blue-green algae, and blue LEDs tend to promote dominance of diatom species. In addition, cyanobacterial clones dominated by red LEDs are closely related to toxin-producing strains and concerned about toxicity. On the other hand, the majority of diatom clones dominated by blue LEDs were closely related to useful species used as food for aquaculture and the like.

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 Coastal recreational areas in Tokyo such as Odaiba Seaside Park have been polluted by combined sewer overflows (CSOs). Surface water sampling was conducted from upstream of the Sumida River to the Odaiba coastal area after rainfall events in October and November 2017. Four types of fecal indicator bacteria (E. coli, Total coliform, Fecal coliform and Enterococcus) and two types of potential viral indicators (F-specific bacteriophage and Somatic coliphage) were analyzed. Immediately after rainfall events, concentrations of fecal bacteria increased by around two orders of magnitude, while an order of magnitude for bacteriophages. Fate of E. coli changed according to the difference in salinity. High correlations were found among four types of fecal bacteria. Cluster analysis results on indicator microorganisms by their fate characteristics indicated that they were categorized into three groups consisting of a subgroup of bacteria and two subgroups of each bacteriophage.

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 It is necessarily that behavior of fish is controlled for preventing fish from entering and fishing with other fishes. For example, there are mothods of the light, the air bubble, the electricity and the magnetic behavior. Mylopharyngodon piceus and Cyprinus carpio is not influenced by the transmitted lig ht, and the transmitted light changes the swimming behavior of juvenile Oncorhynchus keta. It is suggested that the behavior to the transmitted light is different for fish species. Though the influence for Opsariichthys platypus and Candidia temminckii with the transmitted light is verified, the influence for benthic fish is hardly verified. This study was made to verify the influence of contrasting and color of the transmitted light for the swimming characteristic of Anguilla japonica. It is found that the swimming characteristic of Anguilla japonica is not influenced by contrasting and color of the transmitted light.

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 This study investigated high-solids anaerobic digestion of 10-15% influent sewage sludge, combined with pretreatment of waste activated sludge portion. The pretreatment methods employed were thermal treatment of 130 °C and 1 hour at 20 days hydraulic retention time (HRT) for 10% influent, and thermal treatment and ammonia stripping of 80 °C, initial pH of 9 and 3 hours at 30 days HRT for 15% influent. The ammonia concentration in digester was kept at non-inhibitary levels of 2,100 and 3,100 mgN/L for 10% and 15% influent, respectively. Compared with no pretreatmet, VS destruction was improved by 4%, and methane production slightly. At 15% influent, the ammonia of 700 mgN/L in digester was calculated to be removed by the pretreatment, which alleviated severe ammonia inhibition. In coclusion, it is demonstrated that, by applying the pretretreatment, stable and improved performance of high-solids anaerobic digestion can be achieved up to 15% influent sewage sludge.

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 In order to investigate the effect of hydraulic retention time (HRT) on the thermophilic anaerobic digestion of paper-containing organic fraction of municipal solid waste (OFMSW), a lab-scale CSTR was operated. The paper-containing OFMSW consisted of 50% (total solids) of food waste and 50% of paper waste. The HRT in the thermophilic CSTR was shortened from 30 days to 20, 10, 7.5 and 5 days. The performance was evaluated on process stability, biogas yield and organic removal efficiency. The result shows that thermophilic methanogenesis was stable when the HRT was longer than 7.5 days, with high organic removal efficiencies and methane production. When HRT was 30 days, the TS, VS, COD, carbohydrate and protein removal were 78.1%, 79.0%, 78.9%, 91.5% and 29.5%, respectively. No significant decrease in organic removals was observed during the stable operation. The biogas production rate increased in proportion to the organic loading rate and the maximum biogas production rate of 8.51±1.24 L/L/d was obtained at HRT 7.5 days. Whereas, when the HRT was 5 days, the process failed due to the acidification. The first-order kinetic constants and anaerobic reaction rates indicated that the washing-out of propionate-degraders was the cause of process failure in the thermophilic anaerobic digestion of paper-containing OFMSW at 5 days.

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 Anaerobic co-digestion of sewage sludge and grass cultivated using the digested sludge as liquid fertilizer is a promising energy production system in small facilities, where oxidation ditch processes are widely applied. Applicability of this system is experimentally evaluated. Grass cultivation performance in 2 months is 0.24 kg(dry)/m². Components of the cultivated grass are similar to those of grass collected at river and road sides. Mesophilic anaerobic digestion experiments show that biogas production from grass is 0.5 NL/gVS-grass-added, and it is upgraded to 0.6 NL/gVS-grass-added by pretreatment at 80°C for 24 hr. Increase in biogas production by the cultivated grass addition and required cultivation area are within a feasible range. These results show that energy production by grass cultivation using digested sludge can be acceptable.

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 Rice straw recycling system by anaerobic co-digestion was investigated by a questioner survey using conjoint analysis in Kaga city. The result of conjoint analysis showed that “Amount of collection work” was a most important factor for cooperation to a system. “The storage space” and “The price of sewage sludge manure” were next factors. On the other hand, the factor of “The price of rice straw” was minimum. The reason of this result was that 77% of responders are elderly people (older than 60 years old) disliking workload increase. In addition, the result of questioner survey showed that 71% of farmers have tendency to use the recycling system with some kind of benefits.

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 UV light-emitting diode (UV-LED) was investigated in regard to the potential application to aquaculture industry. Vibrio parahaemolyticus, a pathogenic bacterium which often causes problems in the aquaculture industry, was suspended in artificial seawater or phosphate buffer saline (PBS) solution which was then irradiated by UV-LEDs with peak emission wavelength at 265, 280 or 300 nm. Inactivation efficiency was evaluated by cultivation assay. The results revealed that inactivation rate constant, k, in artificial seawater was 0.38, 0.24 and 0.02 cm² /mJ under 265, 280, 300 nm UV-LEDs, respectively, while the k value in PBS was 0.40, 0.28 and 0.02 cm² /mJ under 265, 280, 300 nm emmissions, respectively. Namely, the k value was highest for 265 nm UV-LED in either solution. On the other hand, electric energy consumption required for 3-log inactiveation, E_EL3, in artificial seawater was 0.92, 0.42 and 4.15 kW/m³, and in PBS was 0.80, 0.41 and 4.71 kW/m³ under 265, 280 and 300 nm UV-LEDs, respectively. Thus, electrical efficiency was highest for the 280 nm UV-LED in either solution. This study provides fundamental knowledge on UV-LED applications to aquaculture industry.

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 Livestock that have been administered an antibiotic treatment are highly likely to carry antibiotic-resistant bacteria. Because small animals (mice) live alongside livestock in stock farms and consume their feed and feces, it is possible that these antibiotic-resistant bacteria are transmitted to them. In this study, cattle and mice feces collected from the Sumiyoshi Livestock Science Station, University of Miyazaki, Japan, were tested for the presence of antibiotic-resistant Escherichica coli. Susceptibility of the E. coli isolates from the fecal samples to 11 antibiotics was evaluated using the disk diffusion method. The resistance profiles of E. coli isolates to various antibiotics were evaluated and compared between cattle and mice feces. Antibiotic-resistant E. coli were detected in 50% of cattle (5/10 animals) and 41% of mice (7/17 animals). In addition, all isolates from both cattle and mice feces had high detection rates of antibiotic resistance for ampicillin and tetracycline, and one isolate from the mice feces contained multidrug-resistant E. coli. Examination of the distribution of mice with antibiotic-resistant E. coli suggested that these bacteria are transmitted by mice and can spread to the stock farm.

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 Universal PCR primers targeting 18S rRNA gene of bacterivorous protozoa were designed and used for quantification of 18S rRNA gene in the environment by qPCR. The primers were designed by using consensus regions of 18S rRNA genes that were analyzed in our past researches. Two primer pairs were designed by using around the 500 base and the 1000 base region of 18S rRNA gene, respectively. Copy numbers of 18S rRNA gene in DNA samples extracted from river water were quantified by using each of these primer pairs. There was no significant difference in 18S rRNA copy number between two different primer pairs, showing the validity of the use of them. Also copy numbers of 18S rRNA gene were proportional to those of 16S rRNA gene at a certain range.

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 We investigated the effect of cell wall treatment utilizing high pressure on the CARD-FISH method against Escherichia coli and Rhodococcus equi cells as a Gram-negative and Gram-positive bacteria respectively. As a result, fluorescence signals from both E. coli and R. equi cells could not be confirmed under almost all conditions with high pressure treatment alone. However, it was revealed that by combining high pressure treatment with enzyme treatment such as lysozyme and achromopeptidase, a higher fluorescence signal can be obtained than each treatment alone. It is possible to obtain a strong fluorescent signal even for microorganisms with different cell wall structures by carrying out cell wall treatment with appropriate conditions such as pressure level, treatment temperature, enzyme concentration. It was shown that high pressure treatment can be applied as a versatile and effective cell wall treatment in the CARD-FISH method.

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 In this study, to attempt a development of nematodes control method without chemical pesticide for lotus production field, we performed comparative analysis of microbial communities by difference of disease level, quantitative PCR of parasitic nematodes, and cultivation test of Nelumbo nucifera (lotus) production soil using Bacillus and non-parasitic nematodes predominated compost. As a result of comparative analysis of microbial communities by 16S rRNA genes sequence, microorganisms belonging to uncultured groups in phyla Acidobacteria and Chloroflexi were specifically detected in lotus production field causing replant problem. The result of qPCR targeting parasitic-nematodes indicated that parasitism of Hirschmanniella diversa and H. imamuri occurs in small part of lotus root causing disease. As an evaluation result of effect of Bacillus and non-parasitic nematodes predominated compost, we confirmed that genus Bacillus is able to grow in lotus production field fertilizing the compost.

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 In this study, a fundamental study was conducted for developing new river water quality monitoring system using fluorescence EEM-PARAFAC which had advantages in real time detection and pollution source tracking. Data set including 1219 EEMs was acquired by periodical sampling from 38 sites of the rivers in Saitama Prefecture. Eight PARAFAC components were successfully identified from the data set, in which each fluorophore represented three types of humic substances, two types of amino acids, degradation product of phytoplankton, fluorescent brightener (DSBP) and substance rich in sewage effluent. Multiple regression models using fluorescence components were created for high precise prediction of BOD. In this models, significant indices were found to separately detect and quantify the pollutions from sewage effluent and phytoplankton caused by eutrophication.

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 EEM-PARAFAC analysis was applied to reveal the dynamics of dissolved organic matter (DOM) contained in effluent water in Sewage Treatment Plant (STP) and river water at Katsura-river in wet weather. The objective of this study is to evaluate water quality change of effluent water in STP and river water by combined sewer overflow (CSO) and sanitary sewer overflow (SSO).
 As a result of the water sampling survey, the main component of DOM, which had the largest influence on the quality of river water by CSO and SSO, was a protein-like component.
 The above results suggested that it is effective to constantly monitor this component with a fluorescent sensor as a simple alternative indicator of dissolved organic carbon (DOC) in evaluation of effluent water quality and river water quality by CSO and SSO.

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 In recent years, the difficulties in water utilization related to musty odor which is produced and emitted by benthic cyanobacteria (Phormidium autumnale) has become obvious. Tama River, which is a water resource of Tokyo, has a clear water quality. However, high concentration 2-methylisoborneol (2-MIB) exceeding 200 ng/L produced by P. autumnale was detected from raw water of Ozaku purification plant. As a result, Ozaku purification plant carried out strict powdered activated carbon treatment in order to deal with 2-MIB.
 In this study, we aimed to construct a model equation for the prediction of the short-time transition and the maximum concentration of 2-MIB in order to utilize it for future maintenance and management.By applying the cross-correlation correlogram and multiple regression analysis to water quality data of fiscal year 2015 exceeding 3,000 derived from automatic measuring device in increments of one hour, we constructed a multiple regression model equation for predicting 2-MIB concentration. When a model equation was verified using the water quality data of fiscal year 2016, a high correlation coefficient of 0.853 between the predicted value and the measured value was obtained. As a result, we enable the precise prediction of 2-MIB concentration.

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 In order to maintain the water environment of the inner bay, material cycle in water has to be made clear in physical, chemical and biological aspects. Wind blowing over water surface is one of the major factors that change the flow distribution in the bay. It is important to estimate the spatial variation of wind as appropriate as possible.
 In this study, numerical weather model (WRF) was used for the estimation of temporal and spatial variation of wind and atmospheric pressure at and around the inner bay. And tidal current simulations were carried out using wind distribution calculated by WRF. The results obtained from the application to IMARI bay shows that WRF simulates the observed meteorological variations, such as diurnal variation of wind and temporal changes of atmospheric pressure, with acceptable errors. Furthermore, the spatial distribution of residual currents changes depending on the wind condition given as computational condition. It was implied that the weather condition in the computational area needs to be accurately estimated and WRF which can take the topography around coastal area into account is effective for calculating the airflow at inner bay.

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 A mathematical model was developed based on the theory of transport phenomena in unsaturated soil layers in order to analyze the drying process of the solid waste in the landfill under arid climate. Also, some experiments with an artificial solid waste had been conducted for investigating characteristics of unsaturated water flow including water characteristic curve in solid waste layers and for evaluating validity of the proposed model. As a result, following consequences were obtained. The liquid water flows through the micropores in solid waste layers in the drying process. The proposed model was able to mostly reproduce the evolution of temperature and volumetric water content profile in solid waste layer, which were obtained in an experiment. Finally, the drying process of the solid waste in real-scale landfill was simulated with the proposed model. It revealed that the drying of waste only occurrs near surface region even after 30 years and the drying rate of the waste gradually decreases as it progresses to inside.

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 According to the report in 2015, around 44 million ton of municipal waste was generated every year in Japan. Out of which 80% was incinerated generating around 3.3 million ton of incineration ash which ended in the landfills. Recycling of the incineration ash to cement material has been performed or planned in some local municipalities where the capacity of landfill site was insufficient to meet future demand of ash disposal.
 The permissible chloride content in ordinary portland cement (OPC) is 0.035 %wt, however incineration ash contains higher chloride concentration (0.2-5 %wt). Soluble chloride can be removed by washing with water, but insoluble chloride cannot be washed out because it exists in ash as a stable mineral: Friedel's salt 3CaO·Al₂O₃·CaCl₂·10H₂O. Friedel's salt can be decomposed by many methods like thermal, sulfation and carbonation to remove chloride.
 In this study, the author examined effective method to remove insoluble chloride from ash by carbonation method using wet-CO₂ gas in a column-type reactor. The effects of L/S ratios, gas flow rates and treatment times were studied. It was found that the optimum conditions for effective carbonation were: L/S ratio = 0.3, flow rate = 1000 mL / min, and treatment time = 2 - 3 hours. Using these optimum conditions before rinsing with pure water, the total chlorine content of the incinerated ash after washing was reduced to about 0.5%wt from 1.39 %wt (untreated sample) and the insoluble chlorine content is reduced to about 0.2%wt. Since the insoluble chloride content was reduced to < 0.3%, the ash can be used as one of the component in OPC mixture.

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 The coastal landfill sites are really important and essential infrastructure for our country. However, the decomposition of organic matters and washout of contamination components in these coastal landfill sites are very slow and there is a concern about accelerated stabilization. Researchers show that the fine particle fraction of municipal solid waste incineration ash contains more contamination components. Hence, removing the fine particle fraction from municipal solid waste incineration ash will reduce the contaminants of possessed seawater in the landfill sites.
 Consequently, it is necessary to establish the method to remove fine particle fraction efficiently from incineration ash. This study focused on open channel classification technique. We conducted a demonstration experiment on open channel classification, and investigated the classification effects. A total of three cases were set up by changing the water depth and velocity of the open channel flow, and each experiment was repeated twice for accuracy.
 At first, the velocity of open channel flow was measured using an ultrasonic current mater to determine hydraulic property in the open channel. The velocity fulfilled the experimental conditions around the vicinity of the water surface, but the water has viscosity, this velocity decreased drastically follow the depth of open channel. Next, the particle size distribution of incinerated ash that settled in the open channel was determined, and it was confirmed whether the fine particle fraction division was removed.
 As a result of the experiment, it was found that the decrease of the fine particle division was observed on the upstream side, and the effect of the classification was increased when the water depth and the vicinity value was increased. In the future, we will develop more effective open channel classification technique based on the result of this experiment.

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 Arid countries are facing serious water shortage, and sewage without sufficient treatment is often used for irrigation in some countries such as Egypt. A novel sewage treatment system, a down-flow hanging sponge (DHS) reactor combined with a primary sedimentation tank (PS+DHS system), has been proposed to overcome this issue, but until today its treatment efficiency has not met the Egyptian irrigation standards in terms of fecal coliform (≦5×10³ MPN/100mL). In this study, hydraulic retention time of the DHS reactor was prolonged to 4.8 hours; nevertheless, it was still not able to meet the irrigation standards. Disinfection with copper ion was evaluated, and it was found that the treatment with 2 mg/L of copper ion for at least 2 hours was necessary to achieve the irrigation standards. Growth inhibition and copper ion accumulation were not observed when copper ion-treated water was used for tomato cultivation.

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 Our previous studies proved the low-cost production of protein-rich forage rice with continuous irrigation of treated municipal wastewater (TMWW). Since protein is one of the most important nutrients for animals, the rice cultivated using TMWW potentially have high value as animal fodder. In this study, we conducted two types of examination to evaluate the availability of rice cultivated using TMWW as animal fodder. The first examination to test the feeding preference of beef cattle revealed the rice cultivated using TMWW was consumed by cattle as preferably as the rice harvested in normal paddy fields. In the second examination, the rice cultivated using TMWW was fed to chickens for egg production. Rice-fed-chickens produced eggs similarly to those fed by corn as control. Only the total production of eggs from rice-fed-chickens was slightly smaller probably because the rice was not milled before feeding while the corn was done. Except for this, we did not find any disadvantages in using the rice cultivated with TMWW irrigation as animal fodder instead of corn.

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 Wild oysters and clams were collected at an estuary receiving treated municipal wastewater in Sendai city from two municipal wastewater treatment plants between October 2017 and February 2018 and then examined for Norovirus in their digestive tissues. Norovirus was detected from both oysters (2.2log copies/ g-DT) and clams (2.5log copies/ g-DT) even before the epidemic of gastroenteritis. The concentration of Norovirus GII in the samples obviously increased during the epidemic, while such an increase was not found for Norovirus GI. The concentration of Norovirus GII in the shellfish samples was significantly correlated with the number of gastroenteritis patients reported in the city. This result indicates that reduction of gastroenteritis patients in the city can contribute to improved safety of shellfishes harvested at the downstream.

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 Town A in Fukushima prefecture ordered the residents to evacuate just after the accident at Fukushima Daiichi Nuclear Power Plant. The order was canceled in the next year and the residents started to return. In parallel, a lot of workers for recovery of the affected areas have been staying in the town, resulting in 1.5 times larger population than before the accident. We found the tap water supply has increased and it is approaching to the limit of the existing water treatment plant. We also discussed the effect of dormitories for the immigrated workers on water environment based on the published reports and analysis of water samples, which revealed that septic tanks for the dormitories worked well and discharged water with low BOD. The pollution load estimated from the quality of discharged water was small enough and negligible compared to that in the receiving river. As found in this case, evacuation of residents after nuclear power normally continues for a longer time and involves a wider area than other natural disasters. It is recommended to prepare for accidents of nuclear power plant by sharing tap water supply with neighbor towns, finding desirable location of dormitories for workers and temporary houses, and so on.

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 In developing countries, many tons of valuable nutrients (mainly nitrogen (N) and phosphorus (P)) are lost as waste derived from daily life and agriculture. Nutrient load quantification is an early step for recognizing environmental pollution, and a basic requirement for planning environmental sanitation options. Material flow analysis (MFA) has been used in the environmental sector in many cities of developing countries. In Mandalay, under rapid urbanization, environmental problems have risen to an alarming level. In this study, a nitrogen and phosphorus flow model was developed with a focus on organic waste. The system boundary was five urban townships of Mandalay city and components included in the system were agriculture, livestock, industry, and household. Household surveys, and farmer, livestock owner and industry manager interviews were conducted along with collecting secondary data to develop the model. Results showed that 304 ton-N/year and 258 ton-P/year were discharged from household to the environment as food waste, excreta and greywater. Approximately 3,200 ton-N from on-site sanitation were also annually released to the environment as toilet effluent/leakage and fecal sludge. Animal manure (83 ton-N/year and 16 ton-P/year) and market waste (456 ton-N/year and 71 ton-P/year) were also observed as losses of valuable resources. Applying nutrients from animal manure, fecal sludge, and organic solid waste in the agricultural sector can reduce the pollution load to the environment, and reduce the chemical fertilizer demand in the city.

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 This study proposed a heat-transfer model of a Solar Water Heating (SWH) system using a metal reinforced black polyethylene pipe with a diameter of 10mm. The spirally formed pipe plays the role of a solar heat collector and heat injection in a water storage tank. In this study, an outdoor experiment was conducted to evaluate a performance of SWH system in Fukui, 2014. Some experimental results show that heat-carrier fluid temperature in a heat collection pipe was gradually increased at sunrise and reached at 55°C around 14:00 when short wave radiation flux became maximum. At the same time, the water temperature in the tank also reached maximum 53°C due to heat supply from the heat exchange pipe. It was shown that the proposed model could reproduce the spatial and time variations in the fluid temperature along the pipe for the experiment duration. Furthermore, numerical calculations was carried out to evaluate a reduction in the production cost of hot-water supply for bath by using the model and experimental data. It is expected that the SWH system can reduce the cost of hot water supplied from the gas heater system by 27% in Fukui city.

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 This study proposed a Lining Borehole ground Heat Exchanger (LBHE) using thermosetting resin impregnated glass fiber. Some indoor and field tests were conducted to identify the thermal and strength properties of the LBHE, which are necessary for the practical application. In addition, Thermal Response Test (TRT) was conducted for the LBHE and a double U-tube heat exchanger in the field test. It is seen from the indoor tests that the warp-knitted glass fiber is strong enough to bear the water pressure to inflate during construction and has sufficient elastic property to fit the roughness of the inside borehole. Thermal conductivity of the LBHE (non-treated) and that of the LBHE mixed with a filler were 0.32 and 0.47 W/(mK), respectively. A 100 m long LBHE could inflate by water pressure and the inflated volume of the LBHE attained more than 70% of the borehole volume calculated by a diameter of casing rod. The thermal resistance of LBHE was 0.035 K/(W/m) from the TRT and was lower than that of the double U-tube heat exchanger. It is expected that the LBHE may have a higher heat exchange performance, compared to the double U-tube method.

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 The emissions of greenhouse gases (CH₄, N₂O) from Johkasou were monitored at three sites for over a year, and the seasonal variabilities were analyzed. Based on the annual average emissions, about 90% of CH₄ was emitted from the anaerobic tank and about 80% of N₂O was emitted from the aerobic tank. CH₄ emissions increased when the amount of influent DO into the anaerobic tank decreased. It is caused that the amount of CH₄ production increases due to the progress of anaerobic treatment at the bottom of the anaerobic treatment tank. On the other hand, N₂O emissions increased when BOD and NH₄-N in the tank increased as the water temperature rise period. It is caused that nitrification reaction (nitrite oxidation) in the aerobic tank does not proceed promptly due to elution of BOD and NH₄-N from the stored sludge in the Johkasou.

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 Emission volumes of the greenhouse gas N₂O from small-scale johkasou are around five times higher than those from sewers. In this study, we focused on fluctuations in the flow rate of johkasou and compared the N₂O emission volumes of johkasou with a flow equalization function, for leveling out variations in volume of inflow over time, and of those without. The comparison showed that N₂O emission volumes from johkasou equipped with a flow equalization function are one sixth of those from johkasou without the function or lower. This is because fitting a flow equalization function alleviates the concentration of wastewater that is sent from the primary treatment to the secondary treatment This is believed to be able to minimize the decrease in oxygen reduction potential (ORP) at the secondary treatment. Furthermore, through this study, ORP appears to be a more appropriate indicator for controlling N₂O emission volumes in johkasou than dissolved oxygen (DO).

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 In Johkasou, chlorine disinfection is carried out in order to discharge treated water as hygienically safe. However, adverse effects of residual chlorine and by-product on eco-system at discharged area are concerned. In addition, the total coliforms are used for environmental standard or effluent standard as an indicator; however, the total coliforms include a large number of spontaneous bacterial species. Therefore, nowadays, it is considered that total coliforms are not appropriate as an index for fecal contamination. In this research, we aimed to reveal the behavior of sanitary indicator organisms in each treatment process to develop a johkasou with the minimum amount of chlorine addition, and to clarify the relationship between the removal efficiency and the treatment performance. As a result of the on-site survey, it was suggested that removal efficiencies of total coliforms, Escherichia coli and Enterococcus are correlated with BOD removal in aerobic filter tank and that of anaerobic spore bacteria is correlated with SS removal in anaerobic filter tank, respectively.

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 In order to clarify the particles in the size range of 0.5-1 μm related to residual organic matter in the treated water of gappei-syori Johkasou, the influence of microparticles and bacteria in the treated water tank on the treated water quality was investigated. In addition, the changes of particles and bacteria in Johkasou were analyzed, together with the analysis for their relationships with the residual organic matter in the water of the treated water tank. A statistically significant correlation was found between the number of bacteria and BOD in the water of the treated water tank, indicating bacteria were the major component that contributed to the residual organic matter. The obtained results on the changes of the number concentrations of microparticles and bacteria along the treatment process of Johkasou indicated that most non-bacterial organic particles were removed in the tank of anaerobic filter bed and that most particles in the size range of 0.5-1 μm in the water of the treated water tank were consisted of bacteria. The cluster analysis further indicated that bacteria were the factor that most strongly related to the residual organic matter in the water of the contact filter bed tank and the treated water tank. These results suggested that reduction of bacteria number in the water of the treated water tank is necessary for reduction of residual organic matter in the treated water.

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 To quantitatively investigate fouling layer development in the gravity driven-membrane filtration, we conducted microscopic observation of fluorescently labeled live cells, dead cells, polysaccharides, and proteins in the fouling layers by a confocal laser scanning microscope and quantitatively analyzed volume, average thickness, roughness coefficient, and surface-to-volume ratio of them. In fouling layers developed on PES membranes which had relatively higher flux, live cells distributed mainly in the upper part of the fouling layer. On the other hand, most of dead cells distributed in the bottom of fouling layer due to the substrate deficit in the bottom part of the fouling layer. Polysaccharides distributed in the same region with live cells, which indicates the release of polysaccharides from live cells. The fouling layers of PES membranes had rough and thick structure with high surface-to-volume ratio and large cavity, which contributed to the reduction of fouling resistance. In the fouling layers on PAN memranes, all targeted constitients uniformly and densely distributed on the proximity of membrane surface, which lead to the higher fouling resistance of PAN membrane filtration. These results indicated the significant influence of filtration flux of gravity driven membrane-filtration on the structure of the fouling layer.

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 For mitigation of membrane fouling without increasing power consumption for blowers, a mountain-Type baffle was set between membrane unit and air diffuser to disperse rising air bubbles and provide flat-sheet membranes more uniform velosity profiles. A laboratory experiment was conducted toinvestigate influence of setting patterns of the baffle on trans-membrane pressure increase rate. PIV method was also used for measuring valosity profiles over fla-sheet membrane surface. The baffle was found to be effective for making water-phase velocity profile more uniform and providing more uniform shear stress on membrane surface and was found to be effective method for mitigating membrane fouling without increasing bubble flowrate.

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 Although follow-fiber membranes have been used in many membrane water treatment plants, they are subject to membrane failure during the course of practical usage. Thus, it is important to assess the ageing of follow-fiber membranes for replacement of membrane modules. Therefore, this study aimed to predict the numbers of follow-fiber membrane failure and to estimate appropriate exchange periods of membrane modules. Membrane failure data were obtained from a full-scale plant for the analysis by various statistical models. The acceptable level of log reduction value (LRV) was set at 2.26 based on the raw water quality data of the membrane water treatment plants in Japan and the desirable water quality after membrane filtration. The permissible membrane failure rate was then estimated to be 0.028% to maintain a higher LRV than 2.26. However, based on the water flow model simulation within a membrane module with failed hollow-fiber membrane, it was also found that the LRV of the membrane module is highly dependent on the location of membrane fiber failure. It was demonstrated that both linear model and generalized linear model using logistic regression fit well with the the membrane failure data of a full-scale plant, and can be used to estimate the periods for membrane module replacement. However, binomial distribution model was found to be not suitable for analysis of membrane failure data.

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