By conducting a questionnaire to 60 sewage treatment plants in JAPAN, we investigated the current state of maintenance costs of the six equipment of sewage pump, sludge pump, deodorizing fan, blower, centrifugal dehydrator, centrifugal concentrator, which are the main equipment at sewage treatment plants. Based on the results of this survey, a basic model of the maintenance cost of sewage treatment plants at three treatment plant sizes of 10,000 m³/d, 50,000 m³/d, and 100,000 m³/d was constructed. In addition, using this basic model, two methods for deterioration diagnostic of sewage facilities using ICT adopted for B-DASH project in 2015 was evaluated. As a result, it was suggested that the methods could introduce 2.4 - 20 million yen/year.

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 Coffee grounds are produced about 500,000 tons/year in Japan, and methane fermentation can be an effective treatment method for the waste because energy recovery can be expected. Although there is an actual WWTP producing methane gas by co-digestion with coffee grounds and sewage sludge successfully, unstable condition of coffee grounds fermentation under long time operation is reported and fermentation inhibition can be suspected.
 In this study, a series of batch and continuous experiments for thermophilic methane fermentation of coffee grounds were conducted in order to clarify the inhibition property and find its mitigation methods. Batch experiments examined effects of inhibition in residue of thermophilic methane fermentation of coffee grounds on methane production. The result indicated that inhibition in residue affected methane production due to the accumulation of inhibitor, and that it was possible to reduce the inhibition by treatment with activated carbon. Continuous experiments examined effect of co-digestion of coffee grounds with kitchen garbage. The operation was unstable because of accumulating large amounts of VFA when treating only coffee grounds, but after adding more than 8% of kitchen garbage stable operation was achieved with stable pH and methane production.

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 This study examined super high-solids anaerobic digestion (35°C and 30 days HRT) treating TS 17-21% of sewage sludge. Once a week, ammonia stripping of digested sludge (80°C, initial pH 9 and 3 hours, 120% of the influent) was applied to the digested sludge for reducing ammonia inhibition. The average performance obtained was VS reduction of 53.8% and gas production of 0.470 NL/gVS at the loading rate of 5.20 gVS/L-day, which is almost equivalent to the standard anaerobic digestion of sewage sludge. The ammonia removal efficiency of ammonia stripping was about 75%, maintaining the ammonia concentration at around 3,300 mgN/L in the digester. Although the super high-solids anaerobic digestion can be operated with the ammonia control, there are disadvantages in the viscousity and dewaterability of digested sludge, posing severe problems with subsequent transport and handling processes of the digested sludge.

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 The continuous two-stage thermophilic-mesophilic hythane fermentation of cassava residue with recirculation was conducted over 250 days, to demonstrate start-up strategy by shorting HRT in methanogenic stage, and to investigate nickel, cobalt and sulfur affection on hythane fermentation. Shorten HRT of methane-stage from 80 days to 12 days and maintaining HRT of hydrogen under 3 days was a quick strategy for hythane start-up process. The hythane fermentation of cassava residue under continuous operation without the addition of nutrients resulted in an unstable performance for long-term operation, which was characterized by a radical decrease in the methane production along with a drop in the methane content. The effects of adding Co²⁺ and Ni²⁺, S⁰ and SO₄^2- were discussed in this study. The results of nutrients affection demonstrated the sufficient addition of nutrients could recover and enhance hythane fermentation effectively.

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 Aiging Water Infrastrucure (AWI) and resultant water loss have become serious problems in many water utilities in developed countries. This study aimed to elucidate the current treands of water loss and to analuze factors causing increases of water loss in Japanese water utilities. The data in Statistiacs of Water Utilities in Japan publused by Japan Waterworks Association was used in this study.
 About the water loss percentages have increased between 1993 and 2013 in 55% of the utilities, while it had decreased in 45% of the utilities. Those that increased water loss percentage had more than 10% of water loss, while those that decreased water loss had less than 10% of water loss. Thus, the Japanese water utilities are devided into two groups, and porrly perfoing utilitires are increasing further loss.
 Non-detected pipe breakagges were estimated by employing a novel method using the difference between water loss and theleakage volume that are reported based on the number of repair works nultiples by the leakage volume per repair work. There was ca. 18 times difference in the number of estimated non-detected pipe breakages between high water-loss unilities (H-utilities, water loss ≥30%, n=37) and low water-loss utilities (L-utilities, ≤3%, n=53), indicating that there are numbrous non-detected pipe breakeage in the H-utilities.
 H-utilities had too high planned service population, long pipe length per supply volume, and high water loss per pipe length, whereas L-utilitied controlled water loss per pipe length to be low. Becase water loss percentage increases despite steady volume of water loss, if the revenue water decreases due to future population decrease, it is recommended to use water loss volume per pipe length for controlling water loss.

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 The initial adhesion of micro-particles (>0.45 μm), Mn particles and P. fluorescens to various distribution pipe materials were investigated. Adhesion experiments were conducted using test pieces made of epoxy resin, polyethylene (PE), polyvinylchloride (PVC), high impact PVC (HI). It was demonstrated that, among tested pipe materials, no significant difference was observed for micro-particles adhesion. For Mn particle adhesion, however, a little higher adhesion was observed in epoxy resin and PVC, while PVC showed higher adhesion of P. fluorescens. Since Mn particles and bacteria are minor constituent of suspended matter in treated drinking water, the initial adhesion of suspended matter can be considered to be constant among tested pipe materials.

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 When a large earthquake as large as M7 strikes, concerns arise regarding multiple damages simultaneously occurring on the water pipeline network. However, impact on the entire network system depends on the location of damaged pipes, pipeline network configurations and distribution of water demands among many other factors.
 Therefore, in this research, we proposed a new evaluation index that considers factors such as the shape and regional characteristics of the water distribution network. Additionally, we conducted studies on the method for evaluating renewal priorities considering the impact due to a lot of broken pipes. Damage predictions on water pipes in a Northern Tokyo-bay Earthquake is simulated according to the Monte Carlo method to analyze such factors as the volume of water outage and important facilities impacted by the water outage. The target water distribution zone was divided into 13 blocks and compared to find the relationship between the pipeline network system configuration, the distribution of water demand, and unserviceability. As a result of this comparison, this study proposes two new evaluation indices collectively called Earthquake Disaster Risk Indicators.
 Furthermore, utilization of these new evaluation indices in the water pipeline system renovation scenario analysis demonstrates that it is possible to study and plan a more effective water pipeline system renovation plan.

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 Dili is the capital city of Timor-Leste and has the highest population comparing to other cities. The quality of fresh water streams in Dili was evaluated using the larval himedaka acute toxicity assay combined with active sampling. Ten liters of grab water samples were collected from the Fatuhada, Campo Alor, Caicoli, and Kuluhun streams, filtered and thereafter concentrated using the Sep-Pak^® Plus PS-2 cartridges. Subsequently, the sorbed chemicals were eluted from the Sep-Pak cartridges and prepared for toxicity assays and gas chromatography/mass spectrometry (GC/MS) analysis. Toxicity was evaluated by exposing the larval himedaka (Oryzias Latipes var.) to different concentration ratios (100, 50, 20, and 10 folds) of eluted chemicals and then counting the number of dead himedaka at 0.5, 1, 2, 3, 6, 12, 24, and 48 h during the test. Toxicity results showed that Caicoli had the highest toxicity level, followed by Campo Alor, and then Kuluhun. However, no toxicity was detected in Fatuhada. The lethal dilution ratio (LDR₅₀) values for these streams were; >0.10, 0.07, 0.03, and <0.01, respectively. A comparison was made between Japan and Timor-Leste to show the difference in the toxicity levels of the water streams between the developed and developing countries. The toxicity level in both Timor-Leste and Japanese water streams was high. According to the GC/MS analysis, the detection of coprostanol and many hydrocarbon components of fuel oils in Timor-Leste streams reflects the negative effects of anthropogenic activities on water streams. GC/MS analysis is limited by the number of chemicals that can be identified, and it cannot explain about the effect of the detected chemicals. A further bioassay test is required to assay the toxicities from river water with multicomponent chemicals or chemicals whose toxicity has not yet been evaluated.

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 Chronic toxicity tests provide information about effects on reproduction, but require considerable time and expense. In recent years, metabolomics has been used to predict the effects of contaminants on the reproductive output of organisms. The objective of this study was to predict toxic effects on the estuarine amphipod, Grandidierella japonica, using a model based on metabolic profiles. Metabolomes were extracted from surviving, laboratory-cultured G. japonica exposed to 25, 100, and 250 μg/L copper solution for 10 and 28 days. These metabolic profiles were obtained using an Orbitrap mass spectrometer (Orbitrap MS). Partial least squares regression models showed that metabolic profiles obtained after a 10-day exposure can predict the effect of copper on reproduction after a 28-day exposure. We demonstrated that metabolomic analyses of the estuarine amphipod G. japonica with Orbitrap MS can predict chronic toxicity effects.

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 Highway pollutants which contain micro toxic substances with carcinogenic and/or estrogenic nature such as polycyclic aromatic hydrocarbons (PAHs) have an influence on receiving water. Authors have examined an ecological impact of such highway pollutants on aquatic life using a methodology of Whole Effluent Toxicity (WET) which is usually applied for an effluent management from point sources. From their examinations, one of the findings was that highway dusts which accumulated during a winter season were remarkably toxic in the ecological environment. This study is aimed at investigating characteristics of micro toxic pollutants such as PAHs in highway dusts, and examining their ecological toxicity in terms of PAHs and their transformation products. It is also aimed at showing a mechanism of the remarkable toxicity of the road dust in winter season. Investigations of highway dusts and two types of ecological toxicity tests were carried out. They showed remarkable toxicity of some road dusts both in the field investigations and the laboratory tests. And they also showed that the toxicity could be due to PAHs and their transformation products such as ClPAHs. Some more examinations could clarify a mechanism of ecotoxicity of highway pollution.

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