Enegy recovery from small amount of food residue using methane fermentation technology was studied for on-site energy use with a high efficiency. Amount of food residue from one establishment by business activities was estimated to be less than 1 wet-ton per day. In a conventional methane fermentaion system, it was estimated that a required electricity to operate methane fermentation system is larger than an obtained electricity converted from biogas due to the small amount of food residue. It was suggested that new type of mthane fermentation system, whose digester tank has agitation without driving power and tanks are integrated by removing pumps, was necessary to decrease a required electricity to operate the system. In addition, it was more effective to apply co-digestion of food residue, oil and fats to new type of methane fermentation system in order to increase an obtained electiricity. Greenhouse gas emission per food residue weight for the case of energy recovery with new type of methane fermentation system was evaluated by comparing with the case of incineration or composting food residue.

View full abstract

 Effect of nutrients on hydrogen fermentation of toilet paper under hyper-thermophilic condition was investigated by a lab-scale experiment. The study was conducted with a long-term continuously stirred tank reactor (CSTR) using toilet paper (cellulosic waste) with glucose as co-substrate by anaerobic mixed microflora at 65 ± 1°C. In order to understand the effect of nutrients on metabolic pathway, a series of biogas production, composition and metabolic byproducts analysis was carried out. A maximal hydrogen yield of 1.82 mol H₂/ mol Hexose was obtained at a nutrients condition that support 30% of cells synthesis, with acetate, butyrate and ethanol as main soluble byproducts. The experimental results suggest that amount of nutrients has a greater effect on increasing cellulosic hydrolysis, acidogenesis and the hydrogen yield from cellulosic biomass.

View full abstract

 Anaerobic co-digestion of sewage sludge and ground grass from a riverbed was investigated. We conducted experiments using laboratory-scale and pilot-scale digesters.
 Laboratory-scale experiment was conducted under the condition that the mixture ratio of sewage sludge and grass was 1:0.5 based on TS. The grass was ground to about 2-3 mm in length in pretreatment. This pretreatment got methane conversion efficiency of grass to be almost parallel to that of the sewage sludge. Degradability of grass co-digested with sewage sludge was the same level between those of other two wastewater treatment plants.
 Pilot-scale experiment was conducted in 500L digesters under the same condition of the mixture ratio. The operation was satisfactory and the specific biogas production (SBP) of the grass was 384 NL/kg-VS. This value of SBP was the same level to that of previous study for rice straw pretreated by grinding plus soaking in an enzyme solution.

View full abstract

 Co-digestion of sewage sludge and regional organic waste, such as kitchen garbage, is a promising energy recovery method for small facilities located in remote, and small and medium sized municipalities. Dewatering sewage sludge makes it easier to transport the sludge to a centralized wastewater treatment plant. The effects of sewage sludge characteristics on mesophilic anaerobic digestion performance and digested sludge qualities were investigated by continuous and batch experiments using sewage sludge from seven wastewater treatment plants. Biogas production of sewage sludge from conventional activated sludge processes was 0.4-0.5 NL/gVS, and that from oxidation ditch processes was 0.1-0.2 NL/gVS. This study proposes a simple estimation method for the ammonia concentration and viscosity of digested sludge. The 16S rRNA gene analysis showed different microbial communities under different substrate conditions.

View full abstract

 Methane Fermentation of food wastes generated from food wholesale section and retail trade section was conducted in this study. The characteristics of treatment performance, energy recovery and greenhouse gases emission through methane fermentation process were investigated. The results showed that stable operation were achiveved in both two phase with recirculation and single stage methane fermentation, with the COD and degradation rate of 81.7%〜86.3%, 72.6%〜79.1%, respectively. Amount of energy such as electricity and heat recovered from methane fermentation was likely to be used. In addition, the usableness of perfoming methane fermentation of food wastes also lies in the aspect that along with the reduction of auxiliary fuel and food waste capacity, it is also possible to reduce greenhouse gases emission by about 78%.

View full abstract

 The effect of pretreatment on methane fermentation of food waste by converting carbohydrate in the waste into ethanol using saccharification and ethanol fermentation was studied by batch and continuous experiments. The following results were obtained. (1) The substrate treated by ethanol fermentation had potential biogas generation equal to or higher than the control, and it was considered that the biodegradable component increased. (2) The methane concentration in the biogas increased by a maximum of about 20% and 15% in the batch and continuous experiments respectively compared with the control. (3) Ethanol degradation inhibition was confirmed for ethanol concentrations 2.0 g/L or greater. (4) Even under high initial concentrations, stable methane fermentation was possible because VFA generation was less than in the control. (5) The continuous experiment was able to operate stably for 50 days using the ethanol fermented substrate, and the volume of methane generated was same as the control.

View full abstract

 Because water use systems include a variety of stakeholders, we must present multiple alternative plans that to diverse preferences. Hence, we prepared multiple evaluation axes of water use systems. We developed multi-objective optimization systems that to caluculate multiple alternatives of water use systems by using evaluation model of multiple aspects. We applied cost, water pollution substances, global warming and so on for objective functions, and we applied wastewater treatment plant, supply pipe, treatment plant and so on for design variables. Then, we examined the calculation set using 1,000 sets of random numbers as weighting coefficients and 12 sets of mono-objective optimization. As a result, we could develop multi-objective optimization system. This system can be presented multiple alternatives for stakeholders of multiple preferences. And, we could get 71 Pareto optimal solutions using alternatives by deletion of overlap solutions. These solutions are complementary with each weighting coefficient. These solutions contain unexpected solutions at the stage of weighting by each preferece. These solutions containts multiple value of objective functions and multiple number of dasign variable. Then, we can use these solutions for alternative of decision-making.

View full abstract

 In the Millennium Development Goals, the safe drinking-water target is measured by "access to improved water sources, " and thus does not always reflect the water safety in terms of water quality. Therefore, it is important to develop a method to assess the actual percentages of the population with access to "safe drinking water." The Household Water Treatment (HWT) is one of the possible solutions to improve the safety of water supply; however, their actual use and performance in households remains unknown. In this study, we conducted a face-to-face questionnaire survey (5 communes) and a water quality survey (12 communes) to estimate the population having access to safe drinking water in Hanoi city, Vietnam. Our questionnaire survey revealed that 37-84% of the households used HWTs and that the most prevalent types were Reverse Osmosis (RO) unit in the urban and suburban areas, and Sand Filter (SF) unit in the rural area. Based on the water quality survey, it was estimated that only 11% (n = 23) of the household wells and 35% (n = 23) of the piped water supply samples met WHO guideline values both for arsenic and E. coli. Combining the results of the questionnaire survey and the water quality survey, it was estimated that access to safe drinking water of urban, suburban and rural areas were 60%, 15% and 52%, respectively. These access percentages were estimated to be improved by 13%, 20% and 8%, respectively, by the usage of HWTs, which revealed the important role of HWTs for getting access to safe drinking water.

View full abstract

 This study investigated the water purification and biodegradation characteristics of organic matter in soil aquifer treatment (SAT) with short HRT for indirect potable reuse was discussed. 70.7 and 74.3% of DOC removal from treated effluent was obtained by SAT with HRT of at 3.5 days and 7 days, respectively, and high DOC removal in SAT within HRT of 3.5 days was suggested. From the view pointviewpoint of reduction reducing the formation of disinfection by-products for-mation potential, the effectiveness of SAT with short HRT was also suggested. Analysis of the biodegradation characteristics of organic matter by Biolog EcoPlatesTM cleared indicated that the biodegradation characteristics was were changed through the SAT infiltration with HRT of approximately 1 day in summer, and removal of a diverse range of organic matter by biodegra-dabiodegradation-tion was is expected in SAT with short HRT.

View full abstract

 Domestic water quality survey and question survey were carried out at Palangkaraya City, Central Kalimantan, Indonesia. Although the coliform was not detected from the purified water in the effluent of the treatment plant, coliform were detected from the tap water in the city. The contamination of the tap water by the groundwater was clarified by the composition of the sodium ion and sulfate ion. Some tap water has high turbidity and high color. However, the reason of the high turbidity was not fully clarified. One of the causes was the lack of the continuous monitoring of the turbidity in the water treatment plant.

View full abstract

 Based on the concept that a sewage treatment plant should serve as a base for the circulation of materials and energy in a region, a combined electric power generation system using both digestion gas and sludge incineration for power generation was studied as a second step in the use of organics in influent. To function as a base for the circulation of materials, the plant was assumed to employ phosphorus recovery, which was estimated individually for an ash alkali process and a MAP process. In addition, the effects of accepting garbage, night soil, and jyokaso sludge as regional biomass were estimated. Using a model treatment plant with a capacity of 48,000 m³/day, it was found that introducing high-efficiency solid-liquid separation to recover solid organics proved effective in increasing the electric-power self-supply ratio attained in normal power generation. With digestion gas this ratio was raised from 6.2% to 13.0%, and with combined power generation, the ratio was raised three times higher to 18.6%. Phosphorus recovery was increased by 10% to 30% over the conventional process in an ash alkali process by introducing an AO process using the transfer of phosphorus to sludge as part of the wastewater treatment process. Taking regional biomass into the anaerobic digester was expected to achieve an increase in power generation through an increase in generation from the digestion gas and an increase in phosphorus recovery from the reject water by using the MAP process. When various measures are evaluated in terms of water eco-efficiency from a viewpoint of environmental performance in the sewage treatment plants, power generation using sludge incineration was 1.96 kg/kWh, compared to the benchmark, which was 1.62 kg/kWh of power generation with digestion gas, and phosphorus recovery was 2.08 kg/kWh. The target for water eco-efficiency may be set to 3 kg/kW/h when various measures are combined.

View full abstract

 Several processes for effectively recovering phosphorus have been developed because of its shortage crisis all over the world and serious environmental problems like eutrophication which was attributed to the excess discharge of phosphate compounds. In enhanced biological phosphorus removal processes, activated sludge microorganisms accumulate large quantities of polyphosphate (Poly-P), e. g., under anaerobic-aerobic conditions in wastewater treatment plants. Most of the Poly-P can be released from activated sludge simply by heating it at 70°C for about 1.5h, i. e., 'HEATPHOS' method. Generally, magnesium ammonium phosphate (MAP) which is one of phosphorus recovery materials is crystallized from not Poly-P but orthophosphate (Pi). The purpose of this study is to identify whether the released Poly-P can be crystallized as MAP and to evaluate its forming ability. MgSO₄ and NH₄Cl were added into the supernatant liquid of activated sludge heated at the above-mentioned conditions. Then the amount of Pi, Poly-P, total phosphorus, ammonium-nitrogen, and magnesium contained in the supernatant liquid was measured. The results were as follows. (1)Approximately 47% of the total phosphorus in the heated supernatant liquid was recovered as MAP at pH9.5. In the case of the liquid containing Poly-P, the recovery rate of phosphorus was higher than 'Pi processes' that MAP is crystallized from Pi. (2)The precipitate which was formed from Poly-P contained less Mg than MAP which is recovered by 'Pi processes'. In conclusion, the phosphorus in activated sludge can be more effectively recovered by crystallizing MAP from Poly-P.

View full abstract

 We investigated gene flow of Epeorus latifolium in Shigenobu River (Ehime, Japan) fragmented by 3 types of barriers (i.e. one reservoir dam, 98 weir&check dam, intermittent flow). 112 individuals (13 - 15 individuals / population, average = 14) were collected from 8 populations and genotyped using Cytochrome Oxidase subunit I region in mitochondrial DNA. Among the 3 types of habitat barriers, the weir&check dams showed significant and the highest pairwise Fst between fragmented populations. In addition, the number of weir&check dams was significantly and positively correlated to the level of pairwise Fst (R = 0.81, p < 0.05), suggesting that gene flow of E. latifolium tends to be interrupted in sections with large number of weir&check dams (at least > 14). However, this genetic differentiation found in mountain area could be also explained by the potential process of local adaptation of the populations to the different environmental conditions associated to elevational variation between sites (e.g. water temperature, water flow velocity, UV, oxygen concentration). E. latifolium did not show significant genetic differentiation in the other barrier types of reservoir dam and intermittent flow. It suggests that E. latifolium adults fly over the small-size reservoir dam that we studied (< 0.5 km²) and have adapted life history strategy to migrate across the intermittent sections.

View full abstract

 TOSC (Total Oxyradical Scavenging Capacity) which plays an essential role in cell defense against reactive oxygen species (ROS) apply to the development of environmental monitoring to protect biological system. First, local investigations of TOSC of Stenopsyche marmorata show that TOSC increase according to the growth level between third- and fifth- instar. Therefore, the correction of TOSC with growth level would be needed for applying to environmental monitoring using different wet weight, except immature organisms. Second, to study the effect of river environmental change on TOSC, the specimens were exposed to short term variation in water temperature and turbidity in lab tests. High water temperature caused S.marmorata death in the elevated water temperature test. It indicates the higher water temperature is a strong stress on the species. Therefore, TOSC abrupt decreased compete with ROS caused by stress of high water temperature. Three days later, the survival rate decreased and the TOSC recovered in the stressful condition. TOSC also responds to turbidity over the threshold, regardless of death. As a result, TOSC would be one of the usefull tool to detect effect of short-term environmental change on river organism S.marmorata.

View full abstract

 In this study, to evaluate two dimentional tidal surface habitat, elevation modeling via UAV-SfM mehod was carried out. Especially, the geometric accuracy of elevation models were verified comparing to the RTK-VRS elevation measurements. So as the SfM-derived elevation models are highly sensitive to the relative elevation differences, micro-topography was well modelled in detail. Standard deviations compared to the RTK-VRS elevations were 2.7cm to 5.2cm. Though the appropriate measurements of ground controle points (GCPs) were nessesary, the geometric accuracy of the UAV-SfM elevation model was adaptable to the evaluate tidal benthos habitat and sediment transportion.

View full abstract

 In some lakes, submerged plants have been increased abnormally and have generated floating submerged plants. Several social problems have been occurred due to the submerged plants. In this study, focused on the food chain of the ecosystem in lakes, consumption experiments by using freshwater shrimp were conducted to reduce floating submerged plants. Furthermore, measurements of water quality were conducted to understand a change of water quality in the consumption experiments. Results of the consumption experiments, reduction effects of floating submerged plants by freshwater shrimp can be expected. Consumption were 0.404g-wet/g·day for Ceratophyllum demersum, 0.505g-wet/g·day for Potamogeton crispus and 0.557g-wet/g·day for Myriophyllum spicatum. Furthermore, feeding rate of water plants by freshwater shrimp was found to be larger than the fish. Consumption of water plants were low at 18 °C and 28 °C. Consumption of water plants was the largest at 25 °C. From the above, it can be expected to reduce the water plants by using freshwater shrimp when the water temperature is around 25 °C. From the results of the consumption experiments, deterioration of water quality by freshwater shrimp were less.

View full abstract

 The Ariake Sea has a large tidal range, and therefore, large amounts of suspended solids are transported to the river. The growth and expansion into tidal riverbank of Phragmites australis depends on the sedimentation of mud solids on the riverbank, and the large expansion of P. australis can cause floods. We had proposed the construction of trenches on riverbanks to control the expansion of P. australis; however, their impact on the habitat of aquatic organisms was unclear. The objectives of this study were to provide insights into the aquatic fauna in the trenches and to discuss the association between aquatic fauna and 4 structurally different types of trenches on the banks of the Ushizu River in Saga, Japan. We studied the population of aquatic organisms in each trench using the D-flame net. Shrimps (Exopalaemon holthuis) were predominantly found in all trenches in the summer and autumn seasons. The predominance of goby, Tridentiger bifasciatus, increased in the summer. It was suggested that this results depend on the introduced juvenile of T. bifasciatus into these trenches from river; because it was shown that the result of standard length (SL). While these trends did not depend on the structure of the trenches, our results suggested that specific species, namely Periophthalmus modestus and Cleistostoma dilatatum, prefer shallow trenches as tidal flats. Moreover, we collected more endangered species, Oryzias latipes, and aquatic insects from all the trenches than from the neighboring riverside, suggesting that these trenches have provided a habitat for rare fish and aquatic insects.

View full abstract

 The atmospheric and aquatic PAHs transference processes were discussed using five isomer ratios values of PAHs. The similarity of a pair of datasets of different environment fields or pollution sources for each isomer ratio were calculated as effect size d, and the mean of the d values of five isomer ratios were applied as the index of similarity. From the analysis, diesel emission and/or biomass burning resideus were estimated to be major contributions for almost all the datasets of environmental samples. The pollution loading and path to the PAHs of coastal sediments in Hiroshima bay area were examined and diesel and biomass buring were considered to be major sources for the West side area of the bay and the biomass buring was considered to be for the East side area.

View full abstract

 Biological effects of raw and treated wastewater were evaluated by selecting gene expressions for sexual reproduction and growth in male and female Medaka, and after 96 hour exposure to the samples by comparing the differences in the extent of the gene expressions between control and exposure in the form of Euclidian distance. In addition, reproduction tests using adult Medaka were carried out in the treated wastewater in order to clarify the relationship between the gene expression level and egg laying. As a result, by the treatment of activated sludge process and microbial carrier, biological effects evaluated by the gene expression were reduced to the level of a river with the category of Aquatic life A of the environmental quality standards for conservation of aquatic lives. Also, adverse effect of treated wastewater on the egg laying was not confirmed.

View full abstract

 In this study, continuous experiments were conducted to examine whether application of copper water pipes could control the occurrence of endotoxin (ET) and the regrowth of viable microbes in feed water for healthcare facilities. Three annular reactors were equipped with test coupons made of polycarbonate (PC), stainless steel (SUS) and copper (Cu), and served for the experiments for 49 days. Biofilm samples were collected from the test coupons, then heterotrophic plate count (HPC) and ET activity were analyzed on a weekly basis. At the end of the experiment, 9 microbes were isolated from the biofilm samples and their ET producing capacities were evaluated. Strains of 6 isolates were identified using 16r RNA gene analysis. Growth rate of heterotrophic bacteria on the Cu coupons was much higher than other coupons due to decay of residual chlorine in the reactor accompanied with oxidation of the surface of the Cu coupons. On the other hand, ET activity on the Cu coupons was the least among all of the coupons. It was suggested that the Cu coupons could control specific microbes that have extremely high ET producing capacity, e.g., Pelomonas puraquae.

View full abstract

 The toxicity reduction evaluation of water reclamation using medaka and a gree algais needed for safe applications for landscaping. In this study, toxicity reduction of wastewater by nanofiltration (NF) and reverse osmosis (RO) membranes was evaluated based on algal growth inhibition test by using microplates and short-term toxicity test on embryo and sac-fry stages of medaka fish. NF and RO membranes reduced chronic toxicity to algal growth. While reclamation by RO membrane reduced toxicity to medaka on embryo and sac-fry stages, NF membrane did not reduce the toxicity in the experimental conditions in which the concentration of ammonia was high.

View full abstract

 The removal of nonylphenol (NP) and heavy metals in anaerobically digested sewage sludge was investigated using potassium ferrate as an oxidizer. NP in the aqueous sample was removed with ferrate ion under the weakly acidic conditions more effectively than strongly acidic conditions. The amount of iron required to remove NP was much lower compared to the Fenton process using ferrous ion and hydrogen peroxide. In the sludge sample, almost same amount of iron as the Fenton process was required for NP removal even under the neutral pH condition. The greatest NP removal was achieved at an initial pH of 3.5. As, Cd, Cu and Zn in the sludge were also removed by acidifying the sludge even after the addition of potassium ferrate. These findings suggest that NP and heavy metals could be removed from the sludge by the two-step process composed of oxidation with K₂FeO₄ and acidification.

View full abstract

 Since the fuel revolution in the 1960s, along with the abandonment of community woodlands and the damage inflicted by the pine wood nematode, etc., the Japanese red pine forests have been deteriorating and some have disappeared.
 At present, the decline in biodiversity, aquifer replenishment, and land conservation functions due to the deterioration of community woodlands are considered to be problems.
 Consequently, in this study, with the aim of restoring second-growth Japanese red pine in woodlands, we investigated the colonization characteristics and early tree growth heights of Japanese red pine seedlings in the areas affected by pine die-off. As a result, it was confirmed that on slopes with a thin Ao horizon, the number and survival rate of red pine seedlings was predominantly high. Furthermore, we selected a tree height growth curve that had an exceedingly small error sum of squares, and adequate growth was confirmed when compared with past literature.

View full abstract

 Quantitative vegetation such as number of species, area and coverage of each species and ground level data were obtained from surveys with portable point positing GPS devices for 165 reed communities around Lake Biwa shore from 2008 to 2011 in order to discuss regional characteristics of environmental condition of reed communities for endangered botanical species. Main results are as follows; 1) 13 RDB species of environmental ministry and 25 RDB species of Shiga prefecture were obserbed. 2) Five RDB species (Pogostemon Stellatus, Persicaria hastatosagittata Nakai, Scutellaria dependens Maxim, Galium tokyoense, and Ludwigia epilobioides Maxim. subsp. greatrexii) were obserbed in the reed communities in Harie-region. 3) From examination of relationships between ground level and vertical width of reed communities and the number of endangered botanical species, there tended to be endangered species in the reed communities that had more than 45 cm of vertical width. 4) Reed communities of Harie, Enshouji, Ono, and Shiodu-hama provided favorable habitats for endangered species. Characteristics of environmental condition of them were shown.

View full abstract

 The utilization of steel slag mixed soil as a soil material for seaweed bed has attracted attention in recent years. In this study, a laboratory growth experiment of Zostera japonica (Z. japonica) was conducted to determine the effect of particle size of steel slag on the growth of Z. japonica.
 The results indicated that the growth of Z. japonica in the systems containing more than 2 mm of steel slag were similar to that of the control system without steel slag. Especially, in the system containing 2 to 4mm of steel slag both Z. japonica and diatoms on the surface of sediment grew well. However, in the system containing less than 2 mm of steel slag, the growth of Z. japonica was limited. It was considered that the increase of sediment strength and the lack of phosphorus due to fine particle slag addition caused the growth inhibition of root of Z. japonica. Therefore, when steel slag is used for seaweed bed, not only mixing ratio but also particle size of steel slag should be considered carefully.

View full abstract

 The river administrators often have difficulty with cohesive sediment accumulation/transportation and the vegetation management on the river bank faced to the Ariake sea. These phenomena occur a decrease of cross-sectional area of a river and a lowering of function as the flood flow discharge. Especially, the impediment of water flow caused by spreading of Phragmites australis can't be ignored in the maintaining of the river cross-section. Previous studies have shown the effectiveness of a storage pond and a shielding slab for interrupting progress of the underground root. In this study, four proto-type trenches as a new river structure for the river management are proposed and the field surveys were carried out in the Ushizu river of the Rokkaku river basin. As a result, it was indicated that the water storage trenches supposed for the vegetation management worked to prevent the growth of Phragmites australis. At that time, it will be necessary to maintain more than 0.3m in depth. And a small fence with 0.15 m height around the trench can prevent the inflow of fluid mud with the high concentration. In addition, the result of nutrient concentration makes clear that the influence of the water quality in the trenches is insignificant to the river. Finally, it was shown that series of trenches are useful for the vegetation control.

View full abstract

 This study deals with the cultivation of cloud ear mushroom (Auricularia polytricha) using two food industrial wastes in Amami islands, fermented bagasse and brown sugar shochu lees, as culture media. These materials were found to be better for the mushroom cultivation than the conventional media. The medium containing 85% bagasse and 10% brown sugar shochu lees was the most effective for the cultivation. The fruit bodies obtained from the media could be judged to be a local special product because they were rich in dietary fiber and β-glucan. By the strong absorbing ability of potassium, 41.8% of potassium was removed from the starting media by the mushroom. The results suggest that the potassium amount in the agricultural field will be reduced when the waste media will be used in substitution for the brown sugar shochu lees. As chemical analyses of the waste media showed the lower content of lignin, ADF and NDF, ration digestibility of the waste media from the fermented bagasse and the brown sugar shochu lees is deduced to be higher than the conventional waste media.

View full abstract

 Mineralogical and physical immobilization effects of secondary minral formation by chelate treatment for hazardous elements contained in municipal solid waste incineration (MSWI) fly ash particles were investigated. SEM observation showed that ettringite, which can incorporate heavy metals into its structure, was generated on the surface of fly ash particles after chelate treatment. However, SEM-EDX analysis could not find concentrated spots of hazardous elements on ettringite. This means that mineralogical immobilization of hazardous elements by ettringite is negligible. The same MSWI fly ash particles were observed before and after the moistening treatment in order to investigate physical immobilization effect. These observation showed that soluble components transferred on fly ash particle surfaces and such elemental transfer was inhibited by insoluble mineral formation like gypsum. This means that physical immobilization by insoluble secondary mineral formation can contribute to hazardous elements immobilization to some extent. However, such mineralogical and physical immobilization by secondary mineral formation, which is promoted by fly ash moistening owing to chelate treatment, were limited. Therefore, toxic element immobilization by chelate treatment and its stability would depend mainly on the stability of complexation between toxic elements and chelate reagent.

View full abstract

 In wet climates, leachate formation is inevitable and continues over a long period. However, in arid climates, evaporation considerably exceeds precipitation so that the source of leachate is mainly limited to the water derived from the waste in the landfill. This also implies that leachate generation will eventually cease, and that the waste inside the landfill will gradually dry out. However, to date, this has not been shown quantitatively. In this study, a simple water balance model was created and applied to estimate the time period for which leachate was generated using meteorological data obtained in an arid climate. Several meteorological stations located in arid climates were selected according to the Köppen-Geiger climate classification (in Iran, USA, and Australia), and their climate data from 2000-2013 were used in the model. The configuration of a small trench that exists in landfills in Iran was taken as the landfill form in each location. The results showed that leachate was generated only for the period in which municipal solid waste (MSW) was disposed of because most of the source of leachate was formed by the moisture derived from the waste, and the greater part of the precipitation was consumed by evaporation. Almost no leachate was generated after the end of the disposal operation. This scenario applied for all of the modeled regions. The quantity of water inside the landfill was also calculated. The results from all locations indicated that the quantity of water in the landfill started to decrease after the completion of the waste disposal operation, which implies that the waste inside the landfill will subsequently dry out.

View full abstract

 To investigate the deposition and residual concentration of radiocesium produced as a result of the Fukushima Daiichi Nuclear Power Plant (FDNPP) disaster in a tidal flat, the concentrations of ¹³⁴Cs and ¹³⁷Cs in sediment were measured in Banzu tidal flat, Kisarazu City, Chiba, Japan. The highest radiocesium concentration in sediment, 70 Bq/kg-D.W., was almost the same as the radiocesium concentration recorded in surrounding municipalities in 2011. Since the half-life corrected ratios of ¹³⁴Cs and ¹³⁷Cs were calculated to be from 0.40 to 0.79, it is thus indicated that radiocesium deposited before the FDNPP disaster has remained in the sediment of Banzu tidal flat. Radiocesium concentrations denoted by “derived after FDNPP disaster” and “deposited before FDNPP disaster” were estimated from observational results. The factors affecting the deposition and residual concentration of observational and estimated radiocesium were examined by stepwise multiple regression. Although a different set of factors were indicated by regression analysis for every case, ignition loss was included as a factor in all cases.

View full abstract

 It is considered that accumulation level of radioactive cesium in freshwater fish is higher than that in saltwater fish. However, accumulation pattern of radioactive cesium associated with growth is not fully clarified. To understand it, we measured levels of radioactive cesium and calculated cesium-137/ potassium 40 ratios in different developmental stages of largemouth bass, Micropterus salmoides. Radioactive cesium concentrations of the fish were decreased with hatching, and it increased in juvenile fish due to feeding. The levels of radioactive cesium became 8.6*10² times during six months after hatching. These suggest that change of radioactive cesium concentration during developmental stages of the freshwater fish is dependent on the start time of feeding and the feeding habitat.

View full abstract

 After the Fukushima Daiichi Nuclear Power Plant accident, there was a concern about the influence of radioactive cesium on local park users. This study focuses on the distribution of, and the factors affecting the radioactive cesium in the bottom sediment and hydrophytes of a park lake in the Fukushima prefecture. Surveys of the park lake conducted in 2013 and 2014 yielded the following findings. 1) There is no significant difference between the average ¹³⁷Cs concentrations on the bottom sediment surface measured in 2013 and 2014.2) There is a negative correlation between the ¹³⁷Cs and Si concentrations on the bottom sediment surface. However, there is a positive correlation between the ¹³⁷Cs and K concentrations. 3) The ¹³⁷Cs concentration tends to be highest at the surface of the bottom sediment, and the maximum ¹³⁷Cs concentration depth is different at each investigation point. 4) The proportion of adhesion material in the ¹³⁷Cs concentration of hydrophytes is 33-80%. 5) The transfer factor of ¹³⁷Cs from the bottom sediment to the hydrophytes is 0.03-0.18, which is the same as that found in plants on land.

View full abstract

 We investigated quantities and physicochemical characteristics of iron and organic matters eluted with rain water from soils taken at various kinds of forests and agricultural lands in Shizugawa district, Minamisanriku town, Miyagi prefecture in order to know the relationship of land usage and vegetation with supply of organically complexed iron to coastal area. Organic matters with abundant functional groups, which was indicated by absorption and fluorescence characteristics, were eluted by soils taken at conifer forests and agricultural lands. Iron to organic matter ratios in eluates, which were expected to be related with iron binding capacity, were higher for deep layer in the forests, indicating the importance of iron supply by mother material. Oxidation rate constants of iron by organic matters were also examined since some functional groups attribute to the oxidation of iron. The organic matters with higher aromaticity showed higher oxidation rate constant of iron, and thus, indicated slower production of Fe(II), which has high solubility, in the environmental waters.

View full abstract

 For the purpose of zinc removal of mine water, we have developed a system of lactate solution feeding as organic liquid instead of organic solids, with the aim to keep the reductive conditions and promote sulfate-reducing bacteria activity of wetland. The experiment was conducted in outdoor condition using mine water containing zinc (2.4±0.9mg/l) with a controlled flow rate of 0.2 m³/m²/day for 2 years. Lactate feeding to anaerobic wetland system was controlled by redox potential to maintain desirable Eh for Sulfate reducing bacteria (SRB). The Eh was maintained at -22±268mV when lactate feeding was manually controlled. A stronger redox condition, -165±118mV was achieved by automatic control, resulting in an improvement in zinc removal efficiency from 88% to 93%. Total zinc concentration in bottom layer of wetland near influent entrance was high and the ratio of exchangeable fraction occufied 61%. Although zinc concentration of effluent became higher under low temperature of water, high redox potential and weak acidic pH, it was suggested that zinc removal efficiency was not affected significantly and performance was stable sufficiently.

View full abstract

 To establish the technique of the fast repetition rate fluorometry (FRRF) for measuring primary production rate, we proposed the new method for obtaining the fluorescence value (F_m and F₀) under the dark condition. The results indicated the validity of applying the F_m and F₀ in deep water layer of lake with PAR=0 for their values under the dark condition, especially in the shallow lakes such as Lake Kasumigaura. To assess the validity of the FRRF technique, we compared estimates of primary production rates derived from fluorescence by means of FRRF with those measured using a ¹³C method under laboratory conditions. These comparisons indicate the high correlations between the FRRF and ¹³C techniques; however, the slopes of the regression lines were found to be <1.0 (FRRF < ¹³C). One of the reasons that FRRF underestimated the primary production rates as compared with the ¹³C method is likely the effect of the predominant algal species. Finally, we measured the primary production rates by using FRRF before/after algal bloom in 2012, and it is revealed that the water bloom does not absolutely have the linkage to the rate of primary production.

View full abstract

 The characteristics of natural organic matter (NOM) released from a representative forest soil under acidic, neutral and basic conditions were investigated based on their physicochemical properties and activated carbon adsorbability. For physicochemical properties, it was found that as the releasing condition changed from acidic to basic, NOM components possessing larger UV absorbing capability and larger molecular weight were released into water. The DOC concentration of NOM released under basic condition was tens of times larger than that under either acidic or neutral condition. On the other hand, based on the batch adsorption experiments and isotherm data analysis with a modified Freundlich isotherm model, the differences in the adsorbability of the released NOM were also demonstrated. Compared to the NOM released under either neutral or basic condition, the NOM released under acidic condition was less adsorbable, and NOM components with larger molecular weight seemed to be more preferentially adsorbed.

View full abstract

 Wastewater from livestock facilities shows higher concentration in organics and nutrients than domestic wastewater. In a treatment process of swime farmer in which biological treatment process is installed, effluent contained 17 mgP/L of phosphorus even though 96% of phosphorus was removed in the process. This paper deals with the further removal of phosphorus as calcium phosphate precipitation to show up to 67% of phosphorus was removed by raising pH. In addition, the issues on using softwares for chemical equilibrium reactions is discussed.

View full abstract

 Molecular analysis of pathogenic viruses is promising to evaluate the spread of infectious diseases caused by the viruses. However, current methods can analyze limited region of virus genomes, which hampers detailed virological studies of the viruses. In this study, we developed a recovery method of target viral RNA genome by using hybridization method to be coupled with metagenomic analysis. The optimized method could successfully recover the target virus genome (enteroviruses) at high recovery rate (71%), while the recovery rates of non-target viruses were low (0.19% for Pepper Mild Mottle Virus and 0.18% for Murine Norovirus, respectively). These results clearly demonstrated that the developed method could recover target viral genomes with high specificity and efficiency.

View full abstract

 The presence of enteric viruses in wastewater reflects the occurrence of infectious gastroenteritis in human society. However, because the relative abundance of human viruses to whole viruses in wastewater is extremely small, it is inefficient to detect human virus with metagenomic analysis targeting whole viruses. Then, by using pyrosequencing, we developed a selective metagenomic approach targeting positive-strand RNA viruses to which many human enteric viruses belong. As a result, we detected RNA viruses consisting of 10 genera and 30 species. Among them, human viruses were classified to 3 families (Picornaviridae, Caliciviridae and Astroviridae) and 5 genera (Kobuvirus, Norovirus, Mamastrovirus, Cosavirus and Sapovirus). The ratio of sequence reads of human viruses to identified sequence reads was 23%, which was 10 times higher than other studies with metagenomic analysis targeting whole viruses. In addition, sequence reads of bacteriophages were successfully eliminated, and those of plant viruses that are abundant in municipal wastewater were significantly reduced.

View full abstract

 The relationship between the characteristics of dissolved organic matter (DOM) in treated wastewater and viral adsorption to soil particle during soil aquifer treatment was evaluated. Firstly, batch adsorption experiments were conducted using three kinds of treated wastewater samples. Secondly, the characterization of DOM was performed by fractionating dissolved effluent organic matter into hydrophobic/hydrophilic subcomponents and two size fractions (with molecular weight cut off at 5000 Da), and then virus adsorption to sand was evaluated in the presence of each DOM fraction. The result indicated that DOM in all the tested wastewaters could inhibit virus adsorption and that hydrophobic and high molecular weight (> 5000 Da) fractions contributed to the inhibition of virus adsoption, suggesting the importance of DOM characteristcs on understanding the virus adsorption in soil aquifer treatment.

View full abstract

 Trichloramine is one of the major chlorinous odor compounds in drinking water. Trichloramine formation potential upon chlorination increased after ozonation at actual water purification processes. The formation potential, however, decreased after following activated carbon process. Thus, the levels of the trichloramine formation potential after activated carbon process was similar to or lower than that before ozonation. It was considered that one of the reasons of the increase of trichloramine formation potential after ozonation was the change of the chemical structures of natural organic matter in the process water by ozonation, and the amounts of reaction sites which affected trichloramine formation potential was decreased. It was also condiered that phenolic groups were important reaction sites for this reaction. Trichloramine formation potential upon chlorinataion decreased when free chlorine concentration decreased and pH of the sample increased at 8.

View full abstract

 Chlorination is the most common method used for disinfection of drinking water. However, growing concerns about the potential hazards of disinfection by-products have emerged many efforts to develop alternative disinfection methods. In this study, a new disinfection method was developed using low-dose chlorine in combination with a high level of water-dissolved gas as a chlorine reduction disinfection technique. This research investigated the potential of using pressurized air for the disinfection. It also studied whether the technique using pressurized air could reduce the quantity of chlorine required. First, water containing microbes was chlorinated, which resulted in changes to the physiological features of the microbe cell membranes, and enabling gas to easily penetrate the cell membranes under high pressure. After that, sudden depressurization while the gas inside the cells forming a large amount of bubbles, resulting in the rupture of the microbe and cell death. Pre-chlorination followed by pressurized-air disinfection at 0.6 MPa improved microbial control and was able to reduce by up to 90% the dose of chlorine compared to normal chlorination. The improved disinfection effect was observed after a chlorination period of 10 min before gas treatment. As a result, successful disinfection using a non-greenhouse gas in combination with reduced chlorine treatment may help address recently emerging problems in water disinfection.

View full abstract

 Experiments of MFC for treating liquids of potato, tomato and lettuce as well as potato cubes with different edge lengths of 3, 5 and 7 mm were conducted, and the differences in the removal of organic matter and electricity generation were evaluated. For all three vegetable liquids, organic matter contained was effectively removed (the final removal for COD was 89.6-93.2 %), with slight differences being appeared only in the initial several days. The current density (72.2-100.2 mA/m²) followed the order of potato > tomato > lettuce, while the columbic efficiency varied slightly (15.6-17.3 %). For potato cubes with three different sizes, the obtained results showed the final removal for total COD could reach 88.0-91.8 %, with the cubes of 7 mm revealing a comparatively slower removal rate in the first half of the whole operation for 81 days. The corresponding current density was found to be in the range of 163.3-189.1 mA/m² and the columbic efficiency in the range of 51.5-63.9 %, both following the order of 3 mm > 5 mm > 7 mm. The findings of this study are considered useful for optimization of the composition of vegetable waste, which is normally consisted of liquids and solids of different vegetable types, for treatment by MFCs.

View full abstract

 In the present study, a single chamber Microbial Fuel Cell (MFC) was applied for the treatment of lactate-containing food-processing wastewater to evaluate the efficiencies on electricity generation and organic treatment. Moreover, an open circuit MFC and an acetate-fed MFC were operated for compare of the process performance. As a result, a COD degradation rate of food-processing wastewater by MFC was 1.6 times higher than a COD degradation rate of open-circuit MFC (1.4 kgCOD/m³/day vs 0.9 kgCOD/m³/day). Especially, a degradation rate of propionate of lactate degradation product was increased by the application of MFC system. In addition, the genus Geobacter that is known as the exoelectrogen was observed at the MFC only. This genus was suggested to contribute to propionate degradation, in the lactate-containing food-processing wastewater treatment by MFC system.

View full abstract

 The effects of substrate concentration on the operation performance of Anammox process in a UASB reactor were investigated by a continuous experiment operated at 33ºC. The influent concentration of total nitrogen (TN) was changed periodically to study the performance at each condition. The removal efficiency, Anammox activity and inhibitory factors were also investigated along with the height of the reactor. As a result, at nitrogen loading rate (NLR) of 5.6 kgN/m³/d, the average TN removal ratio reached 83.3% when the influent TN concentration was maintained below 450 mg/L. The sludges sampled from the bottom part of the reactor showed higher specific Anammox activities (SAA) compared to those obtained from the middle and upper parts of the reactor. It was also revealed that when influent TN concentrations were above 550 mg/L, free ammonia and free nitrous acid inhibited the SAA of the sludge at the bottom part of the reactor, resulted in decrease of TN removal efficiency.

View full abstract

 Division of Sustainable and Environmental Engineering, Collage of EnvironmentalTechnology, Muroran Institute ofTechnology In this paper, we evaluated the degradation of alkylphenols at low temperature conditions (4°C) by the combined used of Tween 80 and fungus Penicillium sp. CHY-2 which was isolated from non-contaminated Antarctic soil. Growth of CHY-2 strain and degradation of 4-butylphenol (4-BP) at low temperature was promoted by the addition of Tween 80. Degradation rate of 4-BP was improved about 3 times by addition of Tween 80. Furthermore, Tween 80 was effectively used as a carbon source by CHY-2 strain. Results indicated that Tween 80 is a suitable carbon source than glucose for degradation of 4-BP and growth of CHY-2 strain. Moreover, in addition to the role of carbon source, Tween 80 may also promote the uptake of glucose into intracellular level.

View full abstract

 In the present study, we purified the biphenyl-degrading enzyme 2, 3-dihydroxybiphenyl-1, 2-dioxygenase (BphC) from the bacteria Aquamicrobium sp. SK-2. The BphC was dimer and had molecular weight of 65 kDa. This enzyme showed activity at wide range of temperatures, and from a neutral to an alkali pH, it showed highest activity, at 30°C and pH 8, respectively. The BphC showed K_m (12.0 μM) and V_max(154 mM/min) values with the substrate 2, 3-dihydroxybiphenyl. This result indicated that the BphC had a relatively high affinity with the substrate 2, 3-dihydroxybiphenyl. We analyzed the N-terminal amino acid sequence of the purified enzyme. Sequencing results denoted that the enzyme BphC from SK-2 had high homology (92%) with the enzyme of Pseudomonas sp. KKS102. Based on these results we concluded that BphC was involved in the ring-opening reactions of 2, 3-dihydroxybiphenyl and catechol.

View full abstract

 As suspended solids may cause deterioration of water quality, it is important to obtain knowledge about the behaviors of these contaminants in water distribution pipes. This study analyzed the concentrations and characteristics of suspended solids and bacteria in mortar lined pipes of a water distribution system in japan. Mortar lined pipes are a common feature of such distribution systems. It was reported that the amount of bacteria and suspended solids demonstrate similar behavior to one another. Principal component analysis on the basis of concentrations of suspended elements indicated that the presence of mortar may have had an effect on the suspended solids in the pipes, i.e., the primary component was a factor showing a strong relationship with Al and Ca. In other words, particles containing Al and Ca that were likely derived from mortar used to line the pipes were mixed into the water and thus influenced the suspended solids composition. Although the numbers of bacteria estimated from quinone content exceeded the values in water quality standard for drinking water as discussed in our previous paper, living bacteria were few detected at all sampling sites in this study. This indicates that the bacteria in this study were dead or viable but non-culturable.

View full abstract

 Porous concrete is tried to apply to river as a river bed materials which enhance the amount of attached growth microorganisms and its biological activity. In this study, porous concrete containing zeolite was used as the riverbed materials, and nitrification biofilm forming on the riverbed was targeted. Effects of surface flow rate on nitrification biofilm formation and its activity were investigated. In a range from 5 cm/s to 40 cm/s of surface flow rate, amount of nitrifying bacteria and their activity increased with the increase of the flow rate, and the effects were shown remarkably during the initial stage. Visualization of water flow conditions near surface area of the concrete material was conducted by PTV methods, and both turbulence intensity and Reynolds stress were measured. It was also observed that the both index were increased with the increase of the flow rate. It is verified that surface flow rate give a large effects and its suitable control will give effective purifying techniques of river water.

View full abstract

 Vibration of flat-sheet membrane modules by aeration in the MBRs is thought to influence the increase rate of the transmembrane pressure caused by membrane fouling. In a laboratory scale experiment, influence of the thickness of flat-sheet membrane module on transmembrane pressure increase rate was investigated using artificial activated sludge and three kinds of flat membranes with varying the thickness. The magnitude of the vibration of the membrane sheets was measured by using a laser displacement meter. Although the vibration of thicker flat membrane was smaller, the rate of transmembrane pressure increase was smaller in the thicker module, The shear stress on the surface of membrane sheet caused by aeration was measured and, it was found that larger vibration displacement of membrane sheet causes smaller shear stress on membrane sheet, the mechanism of which was explained by the inhibition of water flow over membrane sheets by the vibration of membrane sheets.

View full abstract