set along the whole river. Bacterial 16S rRNA gene in river water was quantified by real-time PCR. The gene concentration ranged from 2 ×10⁵ to 4 ×10⁵ copies/m L at the uppermost stream point. The gene concentration increased toward downstream, and reached 2×10⁶ to 3×10⁷ copies/m L at the downmoststream point. The increase of 16S rRNA gene copy number was significant in summer. Bacterial population analysis was conducted by Terminal Restriction Fragment Length Polymorphism (T-RFLP). Changes inbacterial community composition were observed in the upstream region. The composition was rather stable in the midstream and the downstream region, however, gradual changes in the composition were observed when water temperature increased.

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In order to clear the phenomena of alkali release from thermal treatment resides after washing off the easily soluble matter, a sequential leaching test of bottom ash (BA), stabilized fly ash (SFA) and slag was conducted with a nitric solution (pH=4). The total alkalinity (TA) in leachate was kept constant with time. The TA at the last sampling was 3-40 meq/L for BA and SFA and 0.1 meq/L for the slag. More than 97% of TA of BA and SFA consisted of residual alkalinity (RA), which was composed of OH^-and IC. TA for BA and SFA was reached to constant within one day, which could not be predicted bythe equilibrium of Ca (OH) ² dissolution. For the slag, H⁺ in leaching solvent was exchanged for Ca and Mg on the surface of the slag. This ion exchange reaction came to equilibrium within one day.

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Heavy metal removal from municipal solid waste incineration bottom ash using organic and inorganic ligands was investigated. Metal mobilization through the complexation with these ligands was evaluated by its leachability based on Japan leaching test 46. 0.02 mol-N/L of ammonium nitrate, sulfate, acetate, oxalate and citrate solutions with/without 0.02 mol-N/L urea were examined. In all cases, pH of the leachates were within the range from 10.4 to 11.0. Ammonium citrate promoted the leachabilityof Cu, Cr, Mn, P, and Fe. Especially, Fe leachability was increased more than 14 times. Ammonium nitrate accelerated only Mg leachability. Other inorganic and organic ligands showed no significant effect on metal mobilization. Under the condition that ammonium oxalate and citrate were co-existed, mobilization of Cu, Cr, Mn, P, and Fe were prohibited compared to those under the condition that only ammonium oxalate or citrate was used. Although urea itself showed no promotive effect on the leachability for most of metals, it accelerated the complexation of Cu, Cr, Mg, Mn, P and Fe with ammonium citrate or nitrate. Correlation analysis of leaching test results indicated strong relationship among Cr, Cu, P. and Mn. Fe and Mn also showed high correlation. This implies the decomposition of minerals that consisted mainly of these elements and it was supported partially by XRD analysis.

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This bench-scale study aimed to demonstrate the feasibility of anaerobic digestion with acidic thermal post-treatment and subsequent phosphorus removal and recovery as ammonium magnesium phosphate (MAP). For this purpose, both wastewater treatment and sludge treatment systems were constructed, and wastewater from combined sewer was treated for 105 days. The anaerobic digestion system showed excellent solids reduction, 65% of SS and 75% of VS S respectively, whereas methane production and sludge dewaterability were at usual levels due to sulfate reduction. PO4-P released from the influent sludge (T-P 287mg/L) reached to 124 mg/L, and was recovered as MAP, which accounts for 43% recovery of phosphorus in the influent sludge. Color in the supernatant was doubled, compared to the influent sludge. Recycle load from sludge treatment to wastewater treatment, however, was insignificant with respect to color and nutrients.

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indicated that non-fibrous carbohydrate was major ingredient and accounted for 44% on average of its dry weight based on food analysis. The coefficient variation that was 15.8% of wet weight meant carbohydrate content was constant compared to other main ingredients. Semi-continuous and batch thermophilic fermentation of the waste under 55°C and pH 5.5 resulted in L-lactate production. In comparison with neutralizer between sodium hydroxide and ammonia water, efficient L-lactate production rate was provided by ammonia water. L-Lactate yield based on initial carbohydrate concentration were 0.63 and 0.69, respectively, in semi-continuous fermentation.

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The authors examined the effect of flooding activities in a greenhouse on the production and emission of nitrous oxide (N₂O) through field observations. Flooding activities affected not only the groundwater quality but also the N₂O gas flux strongly due to the infiltration of a large amount of N₂O, NO^-₃N, SO^2-₄among others, accumulated to the surface soils. Dissolved N₂O and NO^-₃-N in the groundwater decreased by denitrification in the aquifer with clay layer, and the production of N₂O as an intermediate of N₂ through denitrification is smaller than that during flooding activities. The cumulative amount of N₂O gas flux during 1 month just after flooding was estimated to account for 93% of annual flux. This result clarifies that the influence of the flooding activity on the emission of N₂O is extraordinary.

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This study discusses river water quality with extreme precipitation change. We tried to project the water quality change by climate change such as heavy rainfall and lengthening of no rain period, and analyzed the variation ratio of turbidity loadings such as biochemical oxygen demand and suspended solid in Japanese typical rivers according to return period of extreme precipitation. L-Q rating functions and organic pollutants sedimentation model were applied to evaluate water quality during heavy rainfall and during draught period, resepectively.
As results, we are able to point out high risk rivers, which have worse water quality after climate change in Japan. And the following detail results were obtained; 1) In the Ara and the Gouno rivers, turbidity loading increases remarkably with changing rainfall condition.2) The turbidity loading process was clarified by draught period.3) Turbidity loading increases from 200 to 300% in case of a heavy rainfall by climate change in Japan. 4) Turbidity loading increases about 110% in case of longer draught period caused by climate change.

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Enrichment culture of salt-tolerant photosynthetic hydrogen fermentation bacteria, which produce hydrogen with multiple volatile fatty acids (VFAs) was established. The enriched biomass grew well, and produced the hydrogen with lactic acid, acetic acid and butyric acid, which are major metabolites in the wastewater of anaerobic (dark) hydrogen fermentation process. PCR-DGGE analysis revealed that the purple non-sulfur bacteria such as genus Rhodobacter and genus Rhodovulum were predominant in the enrichment biomass. The enriched biomass retained in a reactor, in which installed biomass-carrier, could produce the hydrogen continuously for experimental period (1000 h) under the combinational light irradiation of incandescent lamp and solar lighting system. However, degradation rate of each VFA was different. In both batch- and continuous-cultures, lactic acid was best consumed and acetic acid was also consumed well. On the other hand, the degradation rate of butyric acid was lower than those of other VFAs and most of it was remained in continuous culture.

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The composting toilet with low operation and production cost was developed to evaluate its operation performance and cost. It is a kind of urine diverting toilet with hand mixing device for no power requirement. As a result, weight of composting matrix increased with increasing total weight of loaded feces. The 50% of organic matter was biodegraded. The moisture content increased at initial then became stable at 55%. Organic acids were generated in the matrix at initial, but no acids were detected after 2 weeks. Some inactivation process of pathogens was required, because E-coli and coliform count was higher than conventional composting toilet with heating device. The required force for mixing increased with operation progress, but it could get small by adoption of reducer. However, adoption of reducer causes decrease of rotation number of screw and increase of force loading to the screw, relatively. The loading force from the matrix was increased with increase of weight of mixed matrix and decrease of distance between screw blade and reactor wall. The material cost in Japan was 220000 yen and over half was occupied by production of screw. In Indonesia, it was Rp. 10, 000, 000, (=100, 000 yen) which value is over usual construction cost for toilet. The material cost of PVC for reactor wall occupied 66%.

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The oyster of 20, 000 tons per year (peeled oyster, 2005) is produced in Hiroshima Prefecture. It occupies about 60% of the domestic production, while it is estimated that the bamboo of 5, 500 tons per year used as the main material of oyster farming raft have been scrapped in Hiroshima Prefecture. In this study, seaweed-breeding ground blocks containing charcoal material made from waste bamboo were estimated for probable source of silicate. In the immersion experiments of 272 days, silicateion of 0.82-3.18 gSi/m² was eluted from the bamboo charcoal-containing specimens (weight additional ratio of charcoal: 5-15%). From the result of the diving investigation, it was suggested that the adhesion of seaweed to the bamboo charcoal-containing concrete blocks was rapidly than to blocks without charcoal.

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We identify environmental coalitions which influence growth and survival ratio of the manila clam through field and laboratory experiments, and inspect effects of the maintenance measures of the clam in Wajiro tidal flat. The hardness of the sediment is reduced by tideland cultivation and the softened sediment shows lower temperature when heated by sunlight This shows a possibility of maintaining higher fatness of the clam during summer periods. Setting the protection net on the surface of the tideland prevents the increase of the sulfide in the sediment caused by the corruption of the Ulva, and it maintains the survival ratio of the clam. Consequently, it is shown that these measures are effective for the maintenance of manila clam resources.

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To estimate the filtration capacity by oyster in north Ariake Bay, the oyster reef distribution was measured by using aerial photographs. The total area of the oyster reefs in north Ariake Bay has decreased to about half compared with that in 1978. It results from oyster reef removal for Nori cultivation. Based on field surveys, the oyster size distributions in two typical oyster reefs indicated that the oysters on the reefs are suffered from the ray prey in the unmanaged area. The estimation of oyster filtration indicated that the total filtration capacity via the oyster reef in north Ariake Bay decreased to 10% compared to that in 1978. Using the Box modeling method, effects of oyster cultivation on the amount of plankton was estimated. The cultivation oyster of 200 million pieces for one and half years reduces 360 tons of TN and 30 tons of TP.

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The objective of this study is to build the guide of selecting fish-friendly revetment works by establishing a quantitative evaluation method based on laboratory experiments. Preference experiments are conducted using an experimental channel which has revetment block models in both sides. As the result, when the flow velocity is 50cm/s, many fish except pike gudgeon had a tendency to shelter in blocks. Blocks function as refuses for many fish when the flow velocity is over 50 cm/s in experimental channel. We try to explain fish distribution by using preference values for velocity. Although velocity preference could partly explain the fish distribution when the flow velocity is over 50 cm/s in experimental channel. But when flow velocity is low the fish distribution is could not be explained. So It is found that the review of the preference curve and necessity of other parameters.

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This study was aimed to discuss the phosphorucs omposition of sediments in Inohana Lake, which was a branch lake of Hamana Lake.It wase xpected that the sediment was influenced from riverine suspended solid and influent from Hamana Lake. The riverine suspended solid samples were collected at a major influx river to Inohana Lake during a rain event and low flow period. The bottom sediment samples were gathered at ten points in the lake. Sequential phosphorus extraction techniques was applied to our all collected samples. Extracted microorganism-P much contained the sediment samples of the coastal area, and riverine suspended solid samples. It suggested that riverine particulate phosphorus sedimeted on the coastal area. Non-extractable-P was increased in the offshore points. It suggested that particulate phosphorus changed in quality in anoxic sediment. Phosphorus concentration of interstitial water in sediment was also increased in offshore anaerobic sediment.

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this study, we investigated a method to strengthen water transport between the sediment and the upper water column in a bay, which is induced by ebb and flood tides as a sediment characteristics improvement technique. For using this model, it turned out that the device, an air holder, newly developed to hold air in sediments. Effect of the device was identified by laboratory experiments under varying water pressure at the same level as ebb and flood tides. The simulation model which is estimated a method is able to estimate the effect on water transport with the device. A compared result of laboratory experiments with simulated results, this model is applicable and the device is useful. Several pieces of the device were laid in the sediments at Ivfiike muddy tidal flat in Omuta City, Fukuoka, Japan. Biological effects were identified by measuring mad flat's oxidation-reduction potential (ORP), that is, the sediments turned aerobic.

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The behavior of 17β-estradiol (E2) and estrone (E1) in sediment was studied by batch experiments using sediment from a freshwater reservoir. For this, four sediment columns (two aerobic ones and two anaerobic ones) consisted of 30cm of undisturbed sediment and 60cm of overlying water collected from two sites within the reservoir were used. Moreover, through model simulations, the contribution of sorption and degradation to the behavior of E2 and El was estimated. When E2 was spiked, the ratio of partition coefficients of E2 and El in two aerobic columns, K^E2_d/K^El_d was determined as 9.47 and 7.83, and that in two anaerobic columns as 10 and 8.57, respectively. The degradation rate of El was 33-70% smaller than that of E2. When El was spiked into all columns, the remaining fraction in the overlying water phase and the sorbed fraction onto sediment were higher than experimental runs when E2 was spiked. The degradation rates of E2 and El, and the partition ratio under aerobic condition were larger than those under anaerobic ones. El was more persistent than E2 under both aerobic and anaerobic conditions.

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The purpose of this study is to clarify the origin of organic matters on sediment and the characteristics of temporal variation at an estuarine tidal flat. Silt-clay content (<63μm), chlorophyll a, TOC, C/N ratio and the stable isotope ratio of carbon and nitrogen were measured at three tidal flats around the estuary of the Nanakita River. As a result, organic matters originating from ocean and epiphytic algae greatl contributed to sedimentation of organic matters at Stn.A, sandy tidal flat, though terrigenous organ matters did at Stn.C, muddy tidal flat. On the other hand, Stn.B, the intermediate characteristic of Stn., and C, was affected by particulate organic matters derived from the river water and wastewate Furthermore, it was revealed that the volume and origin of organic matters in the sediments depended c temporal variation, and the factors were different from the Stns, i.e. epiphytic algae for Stn.A, transport of sediments from Stn.A caused by events for Stn.B and the eventual sedimentation of organ matters originating from terrestrial plants, respectively.

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To establish more reasonable standard vales of toxic compounds in drinking water, the infonnation of allocation to drinking water is highly important: This study was designed to estimate allocation of haloacetic acids (HAAs) exposure to drinking water. The exposure amounts via 4 routes (ingestion (drinking water and f ood), inhalation, transdennal exposure), were estimated respectively based on actual concentrations of HAAs in drinking water, air, and food The results indicated that the percentage of dietary exposure to HAAs was greater than other routes in many compounds. Therefore it was considered that dietaty exposure was important in establishing standard values of HAAs in drinking water. In case of dichloroacetic acid and trichloroacetic acid, the median allocations to drinking water were lower than the current default value 20%.

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This study aims at demonstrating health-related incidents caused by drinking water contamination, which occurred in the past ten years of 1997 through 2006 in Japan, and analyzing their risk levels. The information used in this study is those reported to the Ministry of Health, Labour and Welfare according to the “Guidelines for the Implementation of Health Risk Management of Drinking Water”. In the last ten-year period, there were 27 health-related incidents involving 2, 328 cases in Japan among totally 1, 018 incidents reported. The risk levels of health-related incidents were higher at small and private water supply systems compared to those at large water supply systems. Adequate management of small and private water supply system is necessary to prevent heath-related incidents caused by drinking water contamination.

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The results of forecasting domestic water demands in long terms are important for planning water supply facilities and operation and management systems. Recently, structure water demands are being complicated due to the variation of its effecting factors. Therefore, this study was purposed to clear up the factors effecting. Besides, changes of the factors were analyzed by the results of the surveys carried out at intervals. Additionally, the actual situation of intended water usage was analyzed by measurement survey. This study reveals that household composition, lifestyle, spread of equipments, and saving water awareness are the effect factors of water consumption and usage.

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Waterworks in Japan approach to the times of maintenance, and are required to improve their service level of water supply. Preserving or improving of clean water quality management level is one of the important services for water users. The preservation and the improvement might be assisted by introducing useful know-how adopted in other purification plants within similar circumstance. However effective method to find the similarity is not established.
This paper deals with a method to compare a situation of water quality management in purification plants. Purification vector between raw and clean water quality is defined as a situation of water quality management, and relative purification level is discussed according to water source and treatment process. Linear discriminant function reveals statistically significant characteristics of purification plants which distinguish whether water quality is relatively improved or not in similar water sources condition. It concludes importance of mutual communication among similar types of purification plants to find useful know-how.

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The estimation method of accumulated iron rust quantities and also places in water distribution network was proposed by this paper, in order to make an efficient pipe cleaning plan. This study created genetic algorithm (GA) model combined with both the hydraulic pipe network analysis and the estimation method of accumulated iron rust mentioned above, conducted a computer simulation to calculate the amount of iron rust captured by the removal equipment.The purpose of this study is to find out the optimum operation of valves with the GA model, and maximize the captured amount of iron rust.
As the results of the simulation, it became cleared that the GA model could show the open-shut combination of valves which attained the optimum flow condition to capture the iron rust maximum.

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The purpose of this study is to develop an estimation model for the chlorine residual concentration in water distribution systems using an artificial neural network [ANN], and analysis the decreasing residual chlorine with the developed model. This paper focuses on the water distribution reservoir and the water quality control point, and regard the pipe network which exists between those two points as a “black box”.
As the results of cross-correlation analysis and consideration of input factors with the time lag, we created the model which could clearly describe the input-output response of the complex non-linear dynamic system. This study examined some scenarios where the input data (the chlorine residual concentration at the reservoir exit) decreased by 0.05 mg/L, and conducted a simulation with the developed model. It was found that the maximum reducible concentration was 0.10 mg/L, and the reduction range from 15% to 17% was attained compared with the added quantity for the current system.

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One of important subjects on water quality management is to control and to reduce the chlorine residuals concentration in water transmission and distribution systems. This study purposes to evaluate the possibilities in alternatives of chlorine residuals deduction for transmission. We made a filed survey on the Tohnan main line in order to get data for modeling of the chlorine residuals decrease in big size water pipes.
First, we analyze the fluctuations in time series of the measured water quality data. Second, a kinetic model is formulated using the Arrhnius equation with TOC/C0 as a correction factor that is derived from our previous study by laboratory experiments. And this kinetic model is demonstrated to describe the chlorine residuals concentration very clearly. Finally, we examine some scenarios with a chlorine residuals reduction at the reservoir exit. It is found that the advanced water treatment allows us to get more reducible concentration compared with the current treatment.

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An ultra low pressure reverse osmosis (ULPRO) membrane process was applied to defluoridate groundwaters obtained in the Chiang Mai Basin, Thailand. The permeate water contained less than the Thai standard of 0.7 mg/L for drinking water. Although the fluoride rejection rates were high between 94.4-98.4% with all the groundwater samples, the rates went up or down during the course of filtration depending on the groundwater quality. ART-FTIR, in conjunction with saturation index, identified the foulants as Si0₂ and CaCO₃. The fluoride transport models were presented and verified using NaF solutions. The mass-transfer coefficient of fluoride (k) in water was estimated as 3.20 × 10_-5 m/s, and the solute mass-transfer coefficient (k_i) of fluoride through UTC-70U membrane as 1.06× 10-7m/s. Subsequently, the fluoride transport models and the mass-transfer coefficients were used to estimate fluoride concentrations at the gel-layer surface (C_G) and at the membrane surface (C_M). Using these values and the fluoride concentration in the bulk solution (C_B), the changes of the ratios of CA, i/CG and C_M/C_B were calculated to estimate the causes of increase and decrease of fluoride rejection rates during the course of filtration experiments.

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