（Environmental Engineering Research）
Study on effect of tidal flat restoration works for short neck clam (Ruditapes philippinarum)
Sayumi OZOE*, Masahiko SEKINE*, Akihiko HUJII* , Jyunko HAGIHARA*
Tuyosi IMAI* and Takaya HIGUCHI*
*Graduate school of Science and Engineering, Yamaguchi University
The purpose of this research is to estimate the effect of several tidal flat restoration works on improving survival ratio of short neck clam in Yamaguchi bay. By releasing short neck clam with/without protection by net, we test three types of restoration works: 1) turning over the soil, 2) planting bamboo poles, and 3) replacing mud with sand. As a result, survival ratio of juvenile clam is improved by turning over the soil and planting bamboo poles. Replacing mud with sand in the small scale of this experiment shows improvement only during one month. Current simulation reveals that Yamaguchi bay is a source of the clam larva to Suo-nada, rather than receiving larva from outside the bay.
Relationship between sediment quality and benthic macrofauna in Japanese port and harbors
Ryoji NAITO*,**, Yoshiyuki NAKAMURA* , Taro URASE** and Naohiro KANEKO**
*Marine Environment and Engineering Dept., Port and Airport Research Institute
**Dept. of Civil Engineering, Tokyo Institute of Technology
In order to obtain basic information on potential adverse effects of trace chemicals onto benthic fauna, a nationwide survey of sediment quality and benthic macrofauna in Japanese major port and harbors was conducted. Dioxins and heavy metals contents were compared with total wet weight or the number of species of benthic macrofauna. The number of species of macrofauna was found to be more sensitive index to estimate the adverse effects of dioxins than the total wet weight. Heavy metal levels were compared with the benchmark ERL or ERM values. The number of species of macrofauna was associated with concentration of heavy metals. Thus, it is suggested that, in some port and harbors, present level of pollution by heavy metals have adverse effects on macrofauna.
The Effect of Foamed Glass in Mud Improvement of the ARIAKE Sea
Yuji USHIHARA*, Shigenori HAYASHI**, Yutaka HARA*, Yasunari MATSUO*, Yan.Jun.Du**, Daisuke SUETSUGU** and M.Azizul MOQSUD***
*:Technical Research Institute, Nihon Kensetsu Gijutsu Co., Ltd.
**:Institute of Lowland Technology, Saga University
***:Graduate School, Saga University
In this study, mud improvement test to restore the Sinonovacula constricta culture was carried out in the ARIAKE gulf where environmentally polluted, recently. Foamed Glass which is recycled from waste glass, and sea sand were used as mud improvement materials. The effect of mud improvement materials were investigated at both in-situ and laboratory test.
The present condition of ARIAKE gulf mud is difficult to live for benthos, because concentration of sulfide has exceeded favorable limit due to increasing of active bacteria in summer time. In this paper, it was shown that the concentration of TOC and AVS decreased by mixing mud improvement material with mud. And also found that the classification with typhoon and wave was controlled, and the movement of pore water was promoted by mixing foamed glass with mud.
Natural and anthropogenic factors affecting seasonal variation of water quality in Dau Tieng Reservoir, Vietnam
Nguyen Thi Van HA*, Satoshi TAKIZAWA**, Nguyen Vo Minh HAN* and Phan Thi Diem PHUONG*
*: Faculty of Environment, Ho Chi Minh City University of Technology.
**: Department of Urban Engineering, The University of Tokyo.
[Nguyen Thi Van HA] firstname.lastname@example.org
[TAKIZAWA Satoshi] email@example.com
This paper reports the water quality monitoring results of Dau Tieng (DT) Reservoir, which is located in the upstream of Sai Gon River and supplies both irrigation and municipal waters to Ho Chi Minh City and the surrounding areas. DT Reservoir was characterized by seasonal stratifications. In late dry season, i.e. from March to May, anoxic condition was observed at some monitoring stations and chlorophyll a concentration increased. The water quality parameters such as pH, EC, turbidity, DO, temperature, COD, NO2-N, NO3-N, TN, TP, and PO4-P were significantly different in the dry and rainy seasons (t-test, p<0.01). During the rainy season, episodic acidification was also observed and the variation ranges were much higher due to the increase of eroded materials in runoffs entering the reservoir after heavy rainfall. The human activities have deteriorated reservoir water quality. Nutrients from the runoffs associated agricultural activities contributed 73% TN and 30% TP flowing into the reservoir. Fish cage culture and livestock raise in the reservoir added about 15% and 4% of TN, and 36% and 12% of TP, respectively. Regulating fish cage culture and livestock raise will significantly reduce the TP inputs, a limiting factor to algal growth in DT Reservoir in the dry seasons.
Source estimation of nitrogen contamination in groundwaters in Tokyo Metropolitan area
KURODA Keisuke*, FUKUSHI Tetsuo*, TAKIZAWA Satoshi*, AICHI Masaatsu**, HAYASHI Takeshi***, TOKUNAGA Tomochika**
*Dept. of Urban Engineering, Graduate School of Engineering, The University of Tokyo, JAPAN
**Dept. of Environmental Systems, Graduate School of Frontier Science, The University of Tokyo, JAPAN
***Faculty of Education and Human Studies, Akita University, JAPAN
[KURODA Keisuke] firstname.lastname@example.org
[TAKIZAWA Satoshi] email@example.com
With the emergence of rising groundwater problem and the growing importance of groundwater for various uses such as emergency water source, groundwater in urban area is expected to be used for beneficial uses. Hence, the groundwater quality of Tokyo metropolitan area was investigated in order to evaluate the characteristics and pollution. In total 106 groundwater samples were collected from both unconfined and confined aquifers. Nitrogen was the most prevalent contaminant detected from both confined and unconfined aquifers, but geological conditions determined the predominant nitrogen species found in groundwaters. In the western terrace area of Tokyo, only nitrate was detected, whereas in the eastern delta area ammonia nitrogen was predominant in the alluvial sandy aquifer. An estimation of nitrogen source using water balance and land use showed that measured nitrogen concentration exceeded the estimated levels in approximately sixty percent of samples, which indicated leaking domestic wastewater as a possible source of contamination.
The Effect of Reclaimed Wastewater on the Soil and Water Environment Under the Dry-field Irrigation
Takayuki SHIGEMATSU*,Ayako YOSHIDA **, Naoyuki YAMASHITA * and Hiroaki TANAKA *
*Research Center for Environmental Quality Management, Graduate School of Engineering, Kyoto University
**Depertment of Bioproduction Technology ,Tokyo University of Agriculture
[Takayuki Shigematsu] firstname.lastname@example.org
Germination test was conducted with Komatsuna (Brassica rapa var. peruviridis) in order to evaluate the effect on plant growth of reclaimed water provided from demonstration plant which tried to apply the reclaimed wasterwater for dry-field irrigation in Okinawa Island,Japan. From this result, no significant effect on the germination and root extension was observed. We also conducted soil-column experiment to elucidate whether NH4+ and other salts in reclaimed wastewater have an impact on the chemical state and leachate of soil. The soil analysis revealed that as a result of nitrification of NH4+,NO3- is temporarily held in the soil matrix.For cations, by the effect of ion exchange, Na+ increased at the top layer and other cations such as Ca2+,Mg2+ and K+ flowed out with the effluents. It suggested the change of base balance in the soil column. Furthermore, we estimated the mass balance of nitrogen and cations using the result of soil-column experiment. Especially NH4+ and Na+ in reclaimed wastewater moved into the soil matrix, and/or induced ion exchange and nitrification, which then advanced other components to outflow. It was concluded that mass balance estimation can be as a reference index to predict the environmental load of reclaimed wastewater in practical crop cultivation.
Prediction of hydrological regime, plunging and streaming flows, in pool-and-weir fishways
ONITSUKA Kouki*, AKIYAMA Juichiro*, KAWARA Noriaki**, IIGUNI Yohei***, KIUCHI Daisuke****
*:Dept. of Civil Engineering, Kyushu Institute of Technology, JAPAN
**:MATSUO Consultants Co., LTD., JAPAN
***:Dept. of Civil Engineering, Graduate School of Kyushu Institute of Technology, JAPAN
****:Toa Corporation, JAPAN
[ONITSUKA Kouki] email@example.com
Fishways are river constructions which help fish migrating. The pool-and-weir fishway is the most typical type in Japan. There are three types of hydrological regimes in pool-and-weir fishways such as a plunging flow, streaming flow and intermixed flow of plunging and streaming flows. Rajaratnam et al.(1984) clarified that the streaming flow is generated when the normalized discharge is higher than 0.25 and also the streaming flow is generated when the normalized discharge is lower than 0.25. However they substituted the pool length for the overflow depth above the weir, when deriving the normalized discharge from the momentum equation. Such a substitution has a physical problem. Onitsuka et al.(2005) found that the number of parameters of the plunging flow are four. However, it is quite difficult to conduct the systematically experiments. In this study, order comparison of each parameter was conducted based on field data of fishway. As a result, effects of each four parameter on the hydrological regimes was elucidated. New criterion formulas, which can predict the flow regime in the pool-and-weir fishways with three parameters, were suggested.
Study on suitable river bed condition for spawning of ayu
ONITSUKA Kouki*, NAGAYA Takayuki**, SHIRAISHI Yoshiki**, HIGASHINO Makoto***, TAKAMI Tohru***, MATOBA Shinji****, AKIYAMA Juichiro*, OZEKI Hiroaki*****, HATANAKA Hironori******, NAKAGAWA Yumiko*******
*:Dept. of Civil Eng., Kyushu Institute of Technology, JAPAN
**:CTI Engineering Co., Ltd, JAPAN
***:Dept. of Civil Eng., Oita Nat. College of Technology, JAPAN
****:Kyusyu Regional Development Bureau, Ministry of Land, Infrastructure and Transport, JAPAN
*****:Toyota Production Engineering Corporation, JAPAN
******:ACTIS Corporation, JAPAN
*******:Miyako Town, JAPAN
[ONITSUKA Kouki] firstname.lastname@example.org
The ayu, Plecoglossus altivelis altivelis, spawns at the rapid in the lower reach of the rivers, because the velocity is high and also the bed condition is “soft bed”. The soft bed condition is defined by fishermen as that the bed materials move if someone walks on the spawning bed. Fishermen make their efforts to keep soft bed condition during the spawning season. However, it is quite difficult to keep soft bed condition, because they do not know how to make soft bed condition in detail. In this study, the soft bed condition is investigated quantitatively by the field survey. It was found that the soft bed condition is satisfied if the weight of the removed bed material by one step is larger than 0.1kg when someone walks on the river bed. Velocity measurements both in the water and under the bed in the flume were conducted. It was found that the soft bed condition is similar to the critical condition of sediment movement and also that the thickness of the mixing layer between the fixed bed material and moving one increase when the sift bed condition is satisfied.
Study on the Influence on Endangered Species (Lethenteron Reissneri) by Bank Revetment in SAKUTA Ditch
WATANABE Ryoichi*,YAMASAKI Koreyoshi*,SHIMATANI Yukihiro** and KAWAGUCHI Yoichi**
*Dept. of Civil Engineering, Fukuoka University
**Dept. of Urban and Environmental Eng., Kyushu University
SAKUTA ditch is the oldest irrigation channel in Japan. The first description is described in the Japanese Chronicle of Japan that is the Japanese oldest history book. SAKUTA ditch is located in West part of Japan, and it was the point of contact of trade with a continent for a long time. In other words it is the very precious irrigation channel which continues being used for more than 1500 years. According to the field observation results performed in SAKUTA ditch, it becomes clear that 24 species of fishes are existed. In recent years, however, there have been increasing demands from local residents for the creation of the convenient irrigation channel. Authors are observed to clear the effect on endangered species(Lethenteron Reissneri) by bank reventment in SAKUTA ditch. From the observation and experimental results, it is clear that the bed armoring exerts serious influence on Lethenteron Reissneri .
Study on Quantity of Environmental Preference on Ayu with Laboratory Experiments
Hiroyuki NOGUCHI*, Masahiko SEKINE*, Moriyoshi WATANABE** , Masao UKITA*
*:Dept. of Civil Engineering, Yamaguchi University
**:Dept. of Civil Engineering, Akashi National College of Technology
[NOGUCHI Hiroyuki] email@example.com
We define preference curves of Ayu (Plecoglossus altivelis) for velocity, turbulence air bubble and gap of illuminate through laboratory experiments and caluculate weights among these factors. Then, we calculate three dimensional preference patterns in four fishways. Based on the possible fish paths presumed from the preference patterns, we draw preference patterns along the fish paths, which can explain field observations of fish migration. Preference pattern along the fish path obtained from our preference model could be an index to evaluate the effectiveness of a fishway quantitatively.
Genetic diversity and differentiation of Hydrosyche orientalis populations in South-Central Miyagi prefecture
WATANABE Kozo*, KUSANO Hikaru*, OMURA Tatsuo*
*Dept. of Civil Engineering, Graduate School of Engineering, Tohoku University
[WATANABE Kozo] firstname.lastname@example.org
[OMURA Tatsuo] email@example.com
We examined the genetic structure of 58 H. orientalis populations in 6 catchments in South-Central Miyagi prefecture, Japan using AFLP markers. Based on the frequency distribution we observed in values of expected heterozygosity (He), we formulated five categories of He, e.g., <0.136 = very low, 0.136 < He < 0.171 = low, etc. We constructed a dendrogram of the 58 populations using θ, and classified the populations into 3 genetic groups (A, B, C) based on the genetic similarity (e.g., θ< 0.25). Groups A and B were composed of 56 populations that could be divided into upstream (A) and downstream reaches (B) with a boundary occurring between 270 m and 350 m in elevation. Non-overlapping mating seasons that result from different timings of the life cycle was considered to be the cause of this difference in elevational genetic groups. Group C consisted of 2 isolated populations that are both located in narrow headwater streams that are isolated from downstream areas by lentic habitat downstream.
A Principal Component Analysis to Detect Nitrogen-saturated Streams
Tomonori KAWAKAMI1, Yuji NOTO1, Toru AOI2, Naoki MIYAZATO2
and Kunihiro MORI3
1 Dept. of Environmental Systems Engineering, Toyama Prefectural University
2 Dept. of Civil Engineering, Gunma National College of Technology
A principal component analysis was applied to water qualities of stream water to detect nitrogen saturation. Ten physicochemical compositions, such as pH, electric conductivity and ion concentrations including nitrate, were introduced to the analysis. Sixteen nitrogen-saturated streams and 83 non nitrogen-saturated streams collected from Toyama and Gunma prefectures were tested for discrimination between nitrogen saturation and non-nitrogen saturation. The analytical result showed that nitrogen-saturated stream could be discriminated from non-nitrogen-saturated stream by a discrimination line on the axes of a secondary principal component (Z2) and a tertiary principal component (Z3). Meanwhile, some nitrogen-saturated streams were classified into non-nitrogen saturated stream. This might be because the data of stage-3 of nitrogen saturation, the deepest stage of nitrogen saturation, were used to establish the discrimination line. The streams plotted close to the discrimination line, even on non-nitrogen-saturated zone, could be approaching to nitrogen saturation.
Genetic Differentiation Simulation besed on a Individual-Based Model for Aquatic Insect Populations Fragmentad by Riservoir
Yuji KIKUCHI1, Kozo WATANABE2, So KAZAMA1, Tatsuo OMURA2 and Masaki SAWAMOTO2
1Graduate school of Environmental studies, Tohoku University
2Dept. Civil Engineering, Tohoku University
[KIKUCHI Yuji] firstname.lastname@example.org
We developed a model for stream aquatic insect populations to simulate genetic differentiation between fragments above and below a reservoir. The model includes parameters of population size, dispersal rate, mutation rate, and magnitude of habitat fragmentation caused by reservoir. According to the model,
genetic distance (Nei’s Dxy) between the fragments increased following dam construction, and finally reached maximum differentiation within 10-50 generations. We simulated genetic differentiation of Stenopsyche marmorata (Trichoptera, Stenopsychidae) populations based on an observed data set of Dxy
at 6 dam sites, and evaluated the proportion of individuals unable to migrate across the reservoirs due to the dam constriction. The result indicated migration was largely reduced (i.e., 20-60 % individual migrating) in 2 dams and was completely halted where Dxy was highest.
Bromate behavior and chemical formation change in soil-plant system
OHASHI Fumihiko*, SATTA Naoya**, TATEISHI Takahiro***
*:Penta-Ocean Construction Co., Ltd, JAPAN
**:Department of Environmental Science,Faculty of Agriculture, Iwate University, JAPAN
***:Department of Agro-bioscience,Faculty of Agriculture, Iwate University, JAPAN
[OHASHI Fumihiko] Fumihiko.Oohashi@mail.penta-Ocean.co.jp
[SATTA Naoya] email@example.com
In a huge illegal disposal site of the Tohoku region, bromate might be generated by ozonation process in high performance water treatment purifying leachate of the site. Effluent is merged with a river downward, and used as rural irrigation water.
In this research, the growth inhibition of Brassica campestris was examined to estimate effect of bromate on crops. Consequently, bromate indicated inhibitions for growth and germination at the concentration of 10mg/L and 50mg/L, respectively. As good correlation was showed between growth inhibition and bromate concentration, a linear regression equation was obtained. In case of another experiment of 15mg/L bromate solution, growth inhibition estimated by this regression equation was corresponded with experimental result. Bromate was not detected in the edible part of Brassica campestris.
Ligand-Exchange Kinetics of Fe(III)-Citrate Complex with Desferrioxamine B in the Presence of Divalent Metals
ITO Hiroaki*, FUJII Manabu*, SASAKI Shiori*, T. David WAITE**, OMURA Tatsuo*
*:Department of Civil and Environmental Engineering, Tohoku Univercity, JAPAN
**:Department of Civil and Environmental Engineering, The Univercity of New South Wales, Australia
[ITO Hiroaki] firstname.lastname@example.org
We have developed a kinetic model for ligand-exchange reaction of ferric iron-citrate complex (FeCit) with desferrioxamine B (DFB) in the presence of divalent metals (Ca and Mg). The kinetic model considers (1) a disjunctive pathway where DFB binds to Fe following the dissociation of FeCit and (2) an adjunctive pathway where FeDFB is formed via the direct association of DFB to FeCit. The rate constants for the complex reaction in the disjunctive pathway estimated from the model well described the experimentally determined rate constants. In the adjunctive pathway, the reaction rate was found to be affected by the concentrations of divalent cations and citrate. The kinetic data in the adjunctive pathway was well explained by involving the effect of direct association of divalent cation to the precursor complex. The results indicated the significant effect of divalent cations on the kinetics for the ligand-exchange of iron-citrate complex with DFB.
Biodegradation of linearalkylbenzensulfonate by riverine biofilm in the area of no sewage service coverage
Ikumi TAMURA*, Minako OHTA*, Jun SEKIZAWA* and Hiroshi YAMAMOTO*
*Faculty of Integrated Arts and Sciences, University of Tokushima, Tokushima JAPAN
Although the recent sewage service coverage in Japan is approximately 70% based on national population, regional variance is still large and water pollution is still public concern in small rivers and streams in no sewage service coverage area. Since details of biodegradation in urban streams have long been focused on indirect water quality indices such as T-N, T-P, and BOD, few studies have been focused on individual pollutants. In this research, therefore, linear alkylbenzensulfonate (LAS), a popular anionic surfactant, was selected as a target compound. Tokushima Prefecture is known as the lowest sewage coverage in Japan, and we selected six streams of suburban Tokushima city with little sewage coverage, and collected biofilm in three seasons, and the biodegradation rate was investigated. As results, the riverine biofilm sampled from the highly LAS– or NH4+-N contaminated streams showed relatively higher biodegradation rate. In addition, our estimation of the contribution of biofilm to the biodegradation of LAS is relatively higher than suspended bacteria, which suggests the biofilm plays important role in the degradation of LAS in the highly contaminated urban streams with no sewage service coverage.
Control of physically irreversible fouling in microfiltration by pre-coagulation
YAMAMURA Hiroshi*, MAEDA Tomohiro**, KIMURA Katsuki*, WATANABE Yoshimasa*
*:Division of Built Environment, Hokkaido University
[Yamamura Hiroshi]: email@example.com
[Kimura Katsuki]: firstname.lastname@example.org
A long-term filtration experiment with a microfiltration membrane was carried out at an existing water purification plant and the influence of pre-coagulation on the evolution of physically irreversible fouling was investigated. Coagulation carried out at pH 7 mitigated the evolution of physically irreversible fouling. It was found that the degree of physically reversible fouling increased as a result of coagulation. Chemical analysis of the foulant desorbed by NaOH or HCl solution showed that pre-coagulation could prevent the fouling caused by iron, but could not control the fouling caused by organic matters. Particle size distribution of iron in the feed water implied that physically irreversible fouling was caused by the iron of size close to the micro-pores of the membrane (around 0.1 µm) when coagulation was not carried out. The pre-coagulation enlarged the size of iron particles, and would prevent the evolution of physically irreversible fouling. Based on the results obtained in this study, for the control of physically irreversible fouling, the optimum condition of coagulation is determined as follows: the one that can enlarge particles in the feed water with the size that is close to opening of membrane micro-pores.
Influence of bubble size distribution and air flux on membrane surface shear stress in submerged membrane bioreactor
Tairi LI*, , Hiroshi NAGAOKA**
*Dept. of Civil Engineering,Musashi Institute of Technology
** Dept. of Urban and Civil Engineering,Musashi Institute of Technology
This study is aimed at elucidating the mechanism by which rising air bubbles induce shear stress on a vertically set flat-sheet membrane surface.Shear stress on the flat-sheet membrane surface caused by aeration was measured directly using a shear stress sensor. In all experimental conditions, time-averaged upward-direction shear stress on the membrane surface was compared to theoretical shear stress values considering the effect of water flow on membrane surface. Water velocity measurement of bubble flow using Laser Doppler Velocimeter revealed that shear stress working on membrane surface was closely related to upward-direction water velocity. Bubble size measurement of bubble flow using Digital Camera suggested that shear stress working on membrane surface was influenced by bubble size distribution.
Effective Ozonation of Secondary Effluents with Initial Ozone Demand
Eri HASEGAWA*, Harumi YAMADA*, Hiroshi TSUNO*
*:Dept. of Urban and Environmental Engineering, Graduate School of Engineering, Kyoto University, JAPAN
[Eri HASEGAWA] email@example.com
In this study, treatment performances at the initial stage of ozonation were discussed, and the indicators to control ozonation were proposed and estimated. As a results, the ozone consumption during the initial stage of ozonation before dissolved ozone appearance shows the same value with that during initial 20 seconds in batch mode experiment. This initial ozone consumption was defined as initial ozone demand here. The initial ozone demand was 0.3-0.5 mgO3/mgC0 for the secondary effluents of sewage. More than 90% of 17b-estradiol (E2) and brominated organic matters were reduced, and formations of ozonation by-products such as formaldehyde and bromate ion were controlled within this ozone demand. The values of UV254, fluorescence intensity at 345 nm (Excitation)/435 nm (Emission) and that at 240 nm/435 nm can be used as the indicators to conduct ozonation with initial ozone demand, and they were 0.06 /cm, 35 and 15, respectively.
Characteristics of Biological Removal of Organic compounds and Nuitrients in Ozone-Added Activated Sludge Process
Fumitake Nishimura*, Go Katoh**, Taku Fujiwara***, Hirosh TSUNO*, Michiko MASUDA**** and Masahiro WATANABE**
*Dept. of Urban and Environmental Engineering, Kyoto University
**Dept. of Civil and Environmental Engineering, Ehime University
***Dept. of Environmental Engineering, Kohci University
****Dept. of Architecture and Civil Engineering, Nagoya Institute of Technology
[Fumitake Nishimura] firstname.lastname@example.org
Ozone-added activated sludge process is one of the modified processes for reduction of excess sludge production. However, nutrients(N, P) in activated sludge are also dissolved by ozonation in this process, and their concentrations in the effluent become higher as a result. In this study, solubilization characteristics of activated sludge by ozone were firstly investigated, and the treatment methods which seem to be most effective for organics and nutrient removal were selected. Then nitrification-denitrification process was investigated for nitrogen removal in ozone-added activated sludge process. It was shown that organic materials from solubilized activated sludge could be used as electron donors for biological denitrification, and nitrogen removal efficiency was higher in the ozone-added activated sludge process than a conventional activated sludge process in the case that carbon-nitrogen(C/N) ratio was lower in the influent. It is verified that ozone-added activated sludge process is also applicable for nitrogen removal.
Potential inhibitors in long-term operation of thermophilic oxic process
SAGAWA Masahiro*, JEON Kyoung-ho*, NOMURA Munehiro*, CHIBA Nobuo*, NAKANO Kazunori*, NISHIMURA Osamu*
*:Department of Civil Engineering, Tohoku University, JAPAN
[SAGAWA Masahiro] email@example.com
The variation of physical properties of carrier and accumulation of salts in the thermophilic oxic process(TOP) reactor during long-term treatment of swine waste and their influence on decomposition rate of organic waste were examined. During long-term operation treatment test, the of carrier became higher when inhibition of treatment was observed after continuous treatment for 100 days. Since the decomposition rate of organic waste could not be improved completely by destruction of massiveness of carrier, influence of salts accumulated in the reactor was considered not to be negligible. Massiveness of carrier and accumulation of salts during long-term operation of TOP resulted in also low ATP concentration in the reactor, revealing significance of these two factors on reducing microbial activity in the TOP reactor.
Development of Novel Oxygen Supply Apparatus by Contacting Liquid Film with Air
TERAOKA Satoshi, IMAI Tsuyoshi, Zhu Hua, HIGUCHI Takaya and SEKINE Masahiko
Graduate School of Science and Engineering, Ymamaguchi University
[IMAI Tuyoshi] firstname.lastname@example.org
In general, large amount of electric power in a sewage treatment plant is consumed exclusively by operating the aeration process. To save the electric consumption, a novel oxygen supply apparatus was designed to enhance oxygen transfer efficiency by contacting liquid film of target water and its surrounding atmosphere without external electric power needs. In addition to enhance the effective of interfacial contacting area between air and water, some important parameters viz. optimum shape of air bubble collecting parts, etc., were examined for more efficient supply of oxygen in the condition of low air supplied. In this paper, using of relevant parameters related to the performance results of lab-scale experiment was optimized for pilot-scale apparatus designation.
Removal of perfluorochemicals from wastewater by granular activated carbon adsorption
Yong QIU*, Shigeo FUJII**, Shuhei TANAKA*
* : Research Center for Environmental Quality Management, Kyoto University
**: Graduate School of Global Environmental Studies, Kyoto University
[Shigeo FUJII] email@example.com
Perfluorochemicals (PFCs) are widely consumed as surfactants, additives, repellent, insecticides, and so on. Recently some of them have been suspected as persistent, bioaccumulated and toxic chemicals. Reports on PFCs in surface and drinking water indicated ineffective removal in current water treatment facilities including granular activated carbon (GAC) Filtration. This study aims to understand characteristics of GAC adsorption to remove PFCs. Freundlich equation and the homogenous surface diffusion model (HSDM) were applied to interpret experimental data successfully. GAC showed increasing adsorption capacities and velocities for PFCs with longer carbon chain length. Carbon fouling effect reduced GAC adsorption capacities of PFCs more intensively than those of background organics. Coexisting organics and bulk pH did not significantly affect adsorption kinetics of PFCs. Coal-based GAC performed better to remove PFCs than nutshell-based GAC. Preliminary experiments by the raid small scale column test (RSSCT) showed effective removal of some PFCs, including highly concerned perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA).
Investigation of Inductive Effect of Salinity on Nitritation
Kenichi ABE1, Akiyoshi OHASHI1,2, Takashi YAMAGUCHI1, Takaaki TOKUTOMI3
1 Dept. of Civil and Environmental Engineering, Nagaoka University of Technology
2 Dept. of Social and Environmental Engineering, Hiroshima University
3 Kurita Water Industries LTD.
It is still mysterious whether salinity can be an important factor to induce nitrite accumulation in nitrification process. In this study, two airlift reactors with sponge-carriers, fed with an artificial substrate, were operated at 25 and 35˚C to investigate the effect of salinity on nitritation. Even though sodium chloride was stepwise increased to 16 gCl・l-1, the nitrite accumulation could not be found. On the contrary, increasing ammonium loading rate under the same salinity condition, nitrite accumulation accompanied with the proliferation of remaining ammonium. From the result, we can conclude that salinity concentration does not play the important factor for nitritation process.
Nitrogen removal performance of Two Step-Feeding Up-Flow anammox Biofilm Reactor
TAKAHASHI Yoshitaka*, TSUSHIMA Ikuo**, SHIMOKAWA Masaki***
and OKABE Satoshi***
*:Dept. of Environmental Engineering, Hokkaido University
**:Water and Soil Environment Div., National Institute for Environmental Studies
***:Dept. of Urban and Environmental Engineering, Graduate School of Engineering, Hokkaido University
[OKABE Satoshi] firstname.lastname@example.org
The anaerobic ammonium-oxidizing (anammox) process is a new and promising alternative to the conventional nitrogen removal processes. We have previously developed a high rate anammox biofilm reactor. However, no anammox activity was detected at the second half of the reactor even though sufficient amounts of NH4+ and NO2– and high abundance of anammox bacteria were still present. We, therefore, modified our reactor configuration to two step-feeding system and investigated the performance of the modified two step-feeding up-flow anammox (anaerobic ammonium oxidation) biofilm reactor. A nonwoven fabric sheet was used a carrier material of the biomass in the reactor. Synthetic medium was fed into the reactor at the bottom and the middle part of the reactor at the same flow rate. The reactor was operated over 120 days, during which the HRT was gradually reduced to increase the nitrogen loading rate. During the operation with the two step-feeding, pH at the second half of the reactor was maintained below 8.0, which increased the nitrogen removal in the second half of the reactor. Consequently, a maximum nitrogen removal rate of 31.2 kg-N/m3/day was attained. To our knowledge, such a high rate has never been reported before.
Choice Method of Wastewater Treatment System Considering Population Decrease
HOSOI Yoshihiko*, UWAJI Susumu**
*: Department of Social Systems Engineering, Tottori University, JAPAN
**: Sansui Consultants Co., Ltd., JAPAN
[ HOSOI Yoshihiko] email@example.com
[UWAJI Susum] firstname.lastname@example.org
When wastewater treatment system in rural area is decided, two systems which are sewer system and septic tank system are compared according to cost. Though the effect of population decrease is not considered in the previous method, it becomes one of the important factors for public projects.
New method to choose wastewater treatment system was examined considering population decrease. The previous method was revised to consider population decrease. Case studies were carried out on the basis of the new method. There are areas that the septic tank system is chosen even when sewer system is less expensive not considering population decrease. From the point of local government and users, those systems were compared from public subsidy and local bond.
ASM State Variables as Interface for Modelling of Anaerobic Digestion of Activated Municipal Sludge
Hidenari YASUI*, Kazuya KOMATSU*, Rajeev GOEL*, Yu-You LI** and Tatsuya NOIKE***
* * Kurita Water Industries ltd., 1-1, Kawada-Gochoyama, Nogi, Tochigi, 329-0105, Japan
** Department of Civil Engineering, Tohoku University, Aza-Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8579, Japan
*** Advanced research Institute, Nihon University, 4-2-1, Kudan-kita, Chiyoda-ku, Tokyo, 102-0073, Japan
Modifications of entry organic fraction in Anaerobic Digestion Model No. 1 (ADM1) was studied to improve continuity from activated sludge process to the subsequent anaerobic digestion process. In this paper, fractions of Xs, Xh and Xi defined by ASM were compared with those measured under anaerobic condition. Eight datasets from author’s batch experiments and seven datasets from literatures were used for the comparison. It was found that respective ASM state variables were well correlated to those under anaerobic condition, indicating Xc and Xi in current ADM1 structure could be replaced with the three ASM constituents. To explain the fate of Xh in the anaerobic condition, death-regeneration concept was applied where anaerobes grow from the anaerobically decayed Xh with low yield constants that were elaborated through available information of ASM and thermodynamic calculation. As the stoichiometrics have a mutual background, the response of COD compounds in decay stage is possible to use under both aerobic and anaerobic conditions.
Applicability of wastewater characterization by a physical-chemical method for activated sludge modelling
Kazumasa KUDO*, Yoshinari ABE**, Tsukasa ITO** and Tomohide WATANABE**
*:Original Engineering Consultants Co., Ltd., Japan
**:Dept. of Cvil and Environmental Engineering, Gunma University, Japan
There are very few data on wastewater characterization by physical-chemical method to apply Activated Sludge Model (ASM) released by IWA for the wastewater treatment plants in Japan. This study collected the data on wastewater characterization by a physical-chemical method based on the report published by Water Environment Research Foundation (WERF protocol) in a municipal wastewater treatment plant. In addition, COD fractions by three different protocols (typical method using oxygen uptake rate (OUR), guideline in the Netherlands and the WERF protocol) were compared and influence of them on parameter values in ASM2d was discussed. The COD fraction of readily biodegradable organic matter characterized by the WERF protocol was almost same as that determined by guideline in the Netherlands and tended to be greater than that by OUR curve. The COD fraction of inert particulate organic matter (XI) tended to depend on the measured value of amount of waste sludge in the wastewater characterization by the WERF protocol. It was suggested that the activated sludge modeling considering the seasonal variation of COD, nitrogen and phosphorus removals was possible by utilizing ASM2d and wastewater characterization data determined without doing bioassay such as OUR and BOD test.
A Study on Estimation of Sediment Substance Amount in Pipe and Efficient Pipe Cleaning Plan for Water Distribution Network Management
Takaharu KUNIZANE*, Toyono INAKAZU*, Akira KOIZUMI*, Hiroki ARIYOSHI**, Masahiro SHIMOMURA**
*:Graduate school of Urban Environmental Sciences, Tokyo Metropolitan University
**:Saitama Municipal Waterworks Bureau
[Toyono INAKAZU] email@example.com
[Takaharu KUNIZANE] firstname.lastname@example.org
Nowadays, the sum total length of pipeline system (transmission pipes and distribution pipes) amounts to 580 thousand kilometers, and it forms about 70% of the gross assets of the water supply facilities in Japan. Recently, the main concern moves from the construction to the maintenance and management subjects especially for pipeline system. Aging pipelines may be the cause of lower water quality (red water etc.), which makes great damage to many residents.
This paper proposes an estimation method of accumulated iron rust quantities and also places in water distribution network, by applying the distribution network analysis and the simulation of suspended solid’s advection and sedimentation in pipelines. Through an execution of pipeline flushing, we survey the accumulated iron rust in real pipelines, and we confirm the good fitness between the measured value and the calculated iron rust amount by our model. By using this model, we show how to decide the priority sequence for pipeline flushing. As a result, we can suggest an effective pipe cleaning plan to minimize water drain volume of pipeline flushing for water distribution network management.
Factors associated with endotoxin fluctuation in aquatic environment and characterization of endotoxin removal in water treatment process
OHKOUCHI Yumiko*, ISHIKAWA Suguru*, TAKAHASHI Kyosuke**, ITOH Sadahiko*
*: Department of Urban Management, Graduate School of Engineering, Kyoto University
**: Sumitomo Heavy Industries, Ltd.
[OHKOUCHI Yumiko] email@example.com
[ITOH Sadahiko] firstname.lastname@example.org
Endotoxins are well known as bacterial agents to cause strong immunity reaction in human. In this study, several factors associated with increase of endotoxins in aquatic environment were examined. It was suggested that the fluctuation of endotoxic activities could be affected by cell numbers of Synechococcus sp. by comparison with endotoxic activities from different cyanobacterial strains. In Lake Biwa – Yodo River basin, the endotoxic activities ranged from 311 to 2,430 EU/mL, and the effluent from sewage treatment plant were considered to be a major source of endotoxin contamination. The endotoxic activity per an indigenous bacterial cell in aquatic environment was calculated as 5.37×10-4 EU/cell. The removal of endotoxins in water treatment process was also characterized. It was found that endotoxins were increased after activated carbon adsorption process with bacterial regrowth, and that free endotoxin were increased by chlorination. The ratios of free endotoxins to total endotoxins reflected the bacterial cell damages by chlorination or ozonation.
Analyses of Growth Factors of Taste and Odor Producing Algae by a Fuzzy Neural Network
Yoshinobu ISHIBASHI1, Eisaku OIKAWA2, Hiroyuki HONDA3, Tomohiro ADACHI1, and Masahiro NAKATOCHI3
1 Graduate School of Engineering, Tohoku Gakuin University
2 Dept. of Environmental Urban Engineering, Kure College of Technology
3 Graduate School of Engineering, Nagoya University
Growth factors of musty odor producing Phormidium tenue and fishy odor producing Uroglena americana were analyzed by a Fuzzy Neural Network. The factors of the two algae were contrary to each other. Wind speed acted on the growth of P. tenue with a high concentration of nitrate nitrogen and nitrite nitrogen, a certain region of potassium, and other water qualities. The growth of P. tenue was remarkable when over 3 m/s wind blew for approximately 10 days before periodic investigations. Furthermore, the information was proved through interpretation of the previous data and laboratory experiments. For U. americana, the required concentration of potassium was the same as that for P. tenue. However, growth of U. americana was conspicuous when the concentration of nitrate nitrogen and nitrite nitrogen was 0.02 – 0.2 mg/L. When a gentle wind, such as 1 – 1.5 m/s, blew for several to 10 days before periodic investigations, the wind was conducive to growth. The results will be helpful for the prediction and control of an occurrence of musty taste and odor in water sources.
Formation characteristics of haloacetic acids from common chemical structures in dissolved organic matter during chlorination
ECHIGO Shinya*, YANO Yuichi**, JO Ikuko*, ITOH Sadahiko*
*: Dept. of Urban Managament, Graduate School of Engineering, Kyoto University
**: Sumitomo Metal Industries, Ltd.
[ECHIGO Shinya] email@example.com
Chemical identities of the precursors for haloacetic acids (HAAs) formation during drinking water chlorination were characterized by a series of chlorination experiments of common chemical structures in dissolved organic matter. It was indicated that amino acids, b-ketoacids, and b-hydroxy acids were responsible for HAAs formation among various aliphatic structures. Also, among aromatic compounds, phenolic compounds other than chatecols, hydroquinones, and cresols were found to yield significant concentration of HAAs under a typical drinking water treatment condition.
Rejection of Pharmaceuticals and Personal Care Products (PPCPs) by Low Pressure Reverse Osmosis Membrane
OZAKI Hiroaki *, IKEJIMA Norihito **, FUKAMI Koji ***, KOUTO Mutuhisa ****, MATSUI Saburou **
* : Dept. of Civil Engineering, Osaka Sangyo University
** : Graduate School of Kyoto University
*** : Daitetsu Kogyo CO., LTD.
**** : Fudo Tetra Corporation
[OZAKI Hiroaki] firstname.lastname@example.org
This paper aimed to elucidate retention characteristics of some pharmaceuticals and personal care products (PPCPs) by two polyamide low pressure reverse osmosis (LPRO) membranes at various dissociation degrees of the compounds. Feed solution pH did not have influence on rejections of undissociated PPCPs in the pH range of 3 to 10, whereas rejections of other dissociated PPCPs changed drastically with increasing pH especially with loose membrane (UTC-60). Rejections of the PPCPs were most likely governed by size exclusion and electrostatic exclusion, while size exclusion was presumably dominant especially with tight membrane (UTC-70U). However, rejections of perfluorooctanoic acid (PFOA) and perfluorooctan sulfonate (PFOS) were comparatively lower due to the long chain structure of compounds than those of PPCPs. It was also suggested that hydrophobicity of PPCPs molecules might play a role on their rejections by LPRO membranes.
Removal of PPCPs in Secondary Treated Water during Continuous Treatment with UV and UV/H2O2 Processes
Ilho KIM1, Naoyuki YAMASHITA1, Hiroaki TANAKA1, Takeshi TAKUBO2, Tatsuyuki IWASAKI2
1 Dept. of Urban and Environmental Engineering, Kyoto University
2 Iwasaki Electric Co.,Ltd.
The removal efficiency of 41 PPCPs contained in secondary treated wastewater was investigated with continuous UV and UV/H2O2 processes having capacity of 10m3/d. In this study, in order to evaluate the removal potential of UV and UV/H2O2 processes for the PPCPs, a residual ratio that is defined a ratio of a residual concentration of a target PPCP after treatment to its initial concentration was selected at 10 min of contact time in UV or UV/H2O2 process (the amount of energy irradiated : 0.4kWUV•h/m3). For UV process, the residual ratios of 39 PPCPs ranged from 0.003 (diclofenac) ~ 0.867 (ethenzamide), resulting in low degradation for most of the PPCPs investigated except for a few of the PPCPs including diclofenac and sulfonamides. Especially, the residual ratios of ethenzamide, clarithromycin and N,N-diethyl-m-toluamide were 0.867, 0.818 and 0.780, respectively and these values were considerably higher than those of the other PPCPs. On the other hand, for UV/H2O2 process, the residual ratios of most of the PPCPs were less than 0.001, which indicates that UV/H2O2 process would be an effective treatment method when the PPCPs in secondary effluent would be further removed.
Behavior of Dissolved and Sorbed PPCPs in Wastewater Treatment
Takashi OKUDA, Yoshikazu KOBAYASHI, Naoyuki YAMASHITA
and Hiroaki TANAKA
Research Center for Environmental Quality Management, Kyoto University
In recent years, increasing attention has been paid to the fate of PPCPs in the aquatic environment. In this study, we selected 33 PPCPs as target compounds and conducted the surveys in three WWTPs and measured dissolved and sorbed concentration of 33 PPCPs to grasp the behavior in wastewater treatment. As a result, 17 dissolved compounds and 2 sorbed compounds (Levofloxacin and Mefenamic Acid) were detected in influent at more than 100ng/L. Acetaminophen, Theophylline, and Bezafibrate were suggested to be degradable in the biological process, while Sulpirid and Disopyramide were found to be difficult to remove. Carbamazepine was found to be adsorbed to the activated sludge and circulate the bioreactor and secondary clarifier, which suggest that Carbamazepine is less biodegaradable. Ozonation process could decrease the concentration of Sulpirid and Disopyramide, which were difficult to be removed.
Electrochemical treatment of pharmaceutical in water using porous ceramic electrodes
Shogo TANIGUCHI*, Hiroaki OZAKI**, Osamu YAMADA***, Rabindra Raj Giri*
*:New Industrial Reseach and Development Center, Osaka Sangyo University
**:Department of Civil Engineering, Osaka Sangyo University
***:Department of Mechanical Engineering for Transportation, Osaka Sangyo University
[Shogo Taniguchi] email@example.com
This paper aimed to elucidate electrochemical degradations of sixteen common pharmaceuticals and personal care products (PPCPs) (Fenoprofen, Ibuprofen, Ketoprofen, Phenacetine, Naproxen, Indomethacin, Diclofenac, Isopropylantiprine, Clarithromycin, Gemfibrozil, Clofibric acid, Carbamazepine, Phenytoin, Phenobarbital, Methoxsalen and Triclosan) using newly developed porous ceramic electrodes in presence of sodium chloride by laboratory batch experiments. Based on their degradations, the PPCPs were classified into three groups: easily degradable (Isopropylantipyrine, Diclofenac, Naproxen, Indomethacin, Triclosan and Gemfibrozil), degradable in relatively longer time (Phenacetine, Clarithromycin, Methoxsalen and Carbamazepine) and difficult to degrade (Ibuprofen, Ketoprofen, Phenobarbital, Clofibric acid, Phenytoin and Fenoprofen). Adsorption of the PPCPs on electrodes was an important phenomenon. The values for Triclosan; Indomethacin, Clarithromycin and Methoxsalen; and others were about 100%, 30% and less than 20%, respectively. Though free chloride species played an important role on PPCPs removals, the degradations due to free chloride only were significantly smaller than the degradations by electrochemical process. Based on the results of this investigation, it is concluded that electrochemical process with the new porous ceramic electrodes is an efficient and promising oxidation method for PPCPs.
Occurrence of pharmaceuticals in the effluent of wastewater treatment plants and tributaries at Yodo River Basin
SUGISHITA Hiroki*, YAMASHITA Naoyuki*, TANAKA Hiroaki*, TANAKA Shuhei*, FUJII Shigeo*, HOWA Isao**, KONISHI Chie**
*:Research Center for Environmental Quality Management, Kyoto University
**:Murata Keisokuki Service CO., Ltd.
[SUGISHITA Hiroki] firstname.lastname@example.org
The concentrations of pharmaceutical compounds were surveyed in the effluent of wastewater treatment plants (WWTPs) and tributaries at Yodo River Basin by using LC-MS/MS and GC-MS for the quantification. 63 compounds out of 93 were detected at the maximum concentration of 2,000 ng/L. The detection of the 10 compounds among them is unprecedented in Japan. Many compounds were detected in high concentrations in the effluent of the WWTPs. In tributaries, however, 7 compounds were detected in higher concentrations than in the effluent of the WWTPs. In the tributaries where the concentrations of COD and ammonium nitrogen were high, some pharmaceutical compounds were detected also in high concentrations. This result suggests that pharmaceutical compounds are discharged into the river in high concentrations because of inadequate treatment of sewage at the areas with lower sewerage coverage.
Continuous Electrochemical Treatment of Dilute Endcrine Disrupting Chemicals
Hitoshi KASHIMURA*, Yutaka SAKAKIBARA**
*:Pacific Consultants Co., LTD Water and Sewage Planning, JAPAN
**:Dept. of Civil and Environmental Engineering, Waseda University, JAPAN
Continuous treatment of endocline disrupting chemicals (EDCs) were conducted using a 3-dimensinal electrolytic cells process and treatment performances under different operating conditions were analyzed. Experimental results demonstrated that phenolic EDCs (bisphnol-A, nonyle phenol, 4t-octyle phenol, and 17β−estradiol) were removed efficiently and stably by the process and removal rates were fairly in good agreement with calculation results of a mathematical kinetic model constructed based on mass transfer limitation on liquid film on the surface of electrode. Division of electrolytic cells was considerd effective for enhancing the removal performance.
Analytical Development of Pharmaceuticals in Bio-Toilet Compost Using Liquid Chromatography - Tandem Mass Spectrometry (LC/MS/MS)
Yu ONODA*, Ryusei ITO**, Nobuyuki SATO*, Mitsuaki ITO*, Naoyuki FUNAMIZU**
*:Institute of Environmental Ecology, IDEA Consultants Inc.
**:Graduate School of Engineering, Hokkaido University
[Yu ONODA] email@example.com
In this study, we have developed a trace analytical method for pharmaceuticals measurement in bio-toilet compost samples by LC/MS/MS system. Firstly, we tried to create a high-sensitive and simultaneous analytical method with LC/MS/MS for 15 pharmaceuticals. As a result, we have successfully detected all target compounds at 0.013 ～ 1.1 mg/kg level in compost sample. Secondly, we have examined a method of pretreatment including extraction by shaking, supersonication and cleanup by solid phase cartridge for target compounds in compost sample. As a result of recovery test using standard addition method, the good recovery rates, 76-115%, were obtained for 10 out of 15 compounds, except for acetaminophen, atenolol and tetracyclines. From the above-mentioned results, analyzing 10 pharmaceuticals in compost sample became possible. We have analyzed target compounds in compost samples, concentrations of taerget compounds detected by this method was a few mg/kg level and especially, it detected at 35 mg/kg of ketoprofen, which was the highest among target compounds.
Behavior of 17β-estradiol in the completely mixed overlying water phase of sedimented mud cores
Reni Desmiarti1, Fusheng Li2*, Akira Yuasa3, Kanae Inoue2 and Yutaka Suzuki4
1Graduate School of Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
2Department of Civil Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
3 River Basin Research Center, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
[Fusheng Li] e-mail: firstname.lastname@example.org
Four sediment cores (two aerobic cores and two anaerobic ones) consisted of 30 cm of undisturbed sediment and 60 cm of overlying water collected from two sites within a natural reservoir were designed and the behavior of the spiked 17b-estradiol (E2) and its byproduct E1 in the overlying water phase of all cores operated under batch and continuous flow conditions was investigated. By comparing the E2 levels remaining in the effluent from all columns operated for different hydraulic retention times (HRT), the impact of HRT on the fate and behavior of E2 within the sedimented mud columns was assessed, and the differences in the effluent E2 and E1 levels under aerobic and anaerobic conditions were discussed.
Fate of Estrogenic Compounds during Composting Process of Feces with Sawdust Matrix
Ryusei Ito, Naoyuki Funamizu
Graduate school of engineering, Hokkaido university
[Ryusei Ito]: email@example.com
[Naoyuki Funamizu]: firstname.lastname@example.org
Natural hormones, such as estrogenic compounds, are too hard to control, because they are contained in human waste, resulting in requirement of appropriate treatment. However, there is less information about fate of them in composting process of human feces with sawdust matrix. On the other hand, there is no experience to measure the conjugate form of estrogenic compounds, which is discharged from human, in compost containing much contaminant. The aims of this paper are to establish the method to evaluate estrogenic compounds including conjugate in compost and to investigate the fate of estrogenic compounds during composting process. As a result, 17β-Estradiol, this has highest estrogenic activities, and 17β-Estradiol-17β-D-Glucuronide, this is a kind of glucuronic conjugate, were oxidized to Estron and deconjugated to 17β-Estradiol in few days. 17β-Estradiol-3Sulfatet was degraded unknown substance. Estron was biodegraded little, because of no accumulation in long term operation.
Electrolytic Treatment of Trace Toxic Substances in Urine
ONO Taiki*, HAYASHI Masaki*, SAKAKIBARA Yutaka*
*:Dept. of Civil and Environmental Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo, 169-8555, Japan.
[SAKAKIBARA Yutaka] email@example.com
Endocrine Disturbing Chemicals (EDCs) and pharmaceuticals from human beings and livestock origin are excreted via urine. These substances exist in the levels of mg/l in urine and μg/l or less in aquatic environment, respectively. Their effects are of great concern to public health as well as reproductions of aquatic lives. In this study, we investigated the possibility and performance of electrolytic oxidation treatment of 17βestradiol (E2) and tetracycline (TC) in artificially prepared urine (AU) and human urine. In the batch experiments, it was shown that E2 and TC were removed both in AU and human urine. However, removal rates of E2 and TC were smaller than those observed in an AU solution containing only E2 and TC, where these contaminants were almost removed within an hour. Furthermore, removal efficiency of E2 and TC at 1mA was higher than at 0.1mA. These results indicated that if uric acid was removed by a proper treatment with sufficient electric current, E2 and TC in urine could be efficiently removed by the present electrolytic process.
Influence of Dioxin-Contaminated Sediment of the Port of Ichihara on the Sediment Pollution in Tokyo Bay
YAMASAKI Tomohiro* ,MASUNAGA Shigeki**
*：Environmental Engineering Department, Technical Division, Toyo Construction Co., Ltd.
**：Graduate School of Environment and Information Sciences, Yokohama National University
[YAMASAKI Tomohiro] firstname.lastname@example.org
[MASUNAGA Shigeki] email@example.com
High concentrations of dioxins are detected from the sediment of the port of Ichihara. The expansion of pollution to the surrounding area in Tokyo Bay and the pollution of the aquatic life are of concern. In this study, multiple regression analyses using source dioxin congener profiles as independent variables and those in surface sediments from the port of Ichihara to the Tokyo Bay as dependent variables were conducted. The regression analyses used all the dioxin congener data except for OCDD due to the very high concentration of OCDD compared to other congeners. The congener profile of the most contaminated sediment in the port of Ichihara was used as one of the independent source variables. The obtained results showed that dioxins originated from the port of Ichihara spread from the harbor to the south coast of Tokyo Bay, and also to the center of Tokyo Bay. The annual flux of dioxins originated from the port of Ichihara to the whole area of Tokyo Bay was estimated to be 3.2～6.5 g-TEQ/year. This contributes about 6.1% of the total dioxin deposition flux in Tokyo Bay.
Seasonal and regional changes in atmospheric deposition of polycyclic aromatic hydrocarbons in Hokuriku and Tokai districts, Japan
Department of Environmental Systems Engineering, College of Technology, Toyama Prefectural University, JAPAN
Seasonal and regional changes in atmospheric deposition and composition of polycyclic aromatic hydrocarbons (PAHs) were elucidated based on the investigation which was performed at several stations in Hokuriku and Tokai districts, Japan, during two winter seasons from 2003 to 2005. The following conclusions are obtained: (1) In Hokuriku district, atmospheric deposition of PAHs during winter increased at the rural/mountainous stations as well as at the urban/suburban stations. However, the increase was not observed during winter in Tokai district. (2) Cluster analysis was applied to the composition of PAHs. The PAHs composition in Hokuriku district differed from that in Tokai district. Furthermore, there were differences between Minami and Nagoya in Tokai district. In Hokuriku district, the seasonal difference was larger than regional difference. (3) Multi-regression analysis was performed for the effect of meteorological conditions on the change in PAHs composition. Wind direction was the most important factor. Subsequently precipitation and amount of solar radiation were also important.
The flow characteristics of pesticides in Yamato river
OKUMURA Yoichi1, TSUJIMOTO Akiko TSUJIMOTO1 , Yoshinori KANJO1, Satoshi MIZUTANI1
1Graduated School of Engineering ,Osaka city university
[OKUMURA Yoichi] firstname.lastname@example.org
[KANJO Yoshinori] email@example.com
Flow characteristics of pesticides in Yamato River are investigated from the survey of nine months at the downstream of the river. Ten kinds of pesticides in 16 targeted pesticides were detected. All pesticides were lower than the environmental standard value in Japan, althogh propizamid, a herbicide, was detected in comparately high concentrations. Most of pesticides in the river existed in dissolved form. The fungicide and herbicides concentrations were not correlated with the concentrations of general water quality index .The maximum concentrations of bromobutide, benthiocarb, diazinon and isoprotihiolane in Yamato River were from one to two order higher than those of Yodo river.
The Flow Characteristics of Polycyclic Aromatic Hydrocarbons(PAHs) in Yamato River
ITO Yuichi*, HAYASHI Naoto*, KANJO Yoshinori*, MIZUTANI Satoshi*
*:Graduate School of Engineering,Osaka City University
Behavior of polycyclic aromatic hydrocarbons (PAHs) at the downstream of Yamato River was studied. River water were surveyed once a week for a duration of May to December in 2006, and the sediments were surveyed twice in October and November, 2006. In the river water, T-PAHs concentration changed widely from 8.9 ng/L to 286 ng/L, and tend to be higher when it rained within 24 hours. Benzo[b]fluoranthene and benzo[k]fluoranthene (with 5-rings) were detected in all of the 31 samples of water. On the other hand, anthracene (with 3-rings) and indeno [1,2,3-cd] pyrene (with 6-rings) were not detected in many samples. Indeno [1,2,3-cd] pyrene was only detected in rainy days’ samples in the form of P-PAH. The level of PAHs with 2 or 3 rings in rainy days were almost same as those of sunny days, whereas PAHs with 4 to 6 rings were about 2 to 4 times higher. T-PAHs in the river sediments at the point of receiving road drainage of the Abiko-ohashi bridge was much higher than that at the other points.According to the Chemical Mass Balance method, it was presumed that the sources of PAHs were asphalt and gasoline.
Leaching property and valence change of antimony (V) from intentionally polluted soil
SATTA Naoya*, HIKAGE Ikue**, FUKUTANI Satoshi***
*:Department of Environmental Science,Faculty of Agriculture, Iwate University, JAPAN
**:The Tohoku Regional Bureau, Ministry of Land, Infrastructure and Transport, JAPAN
***:Research Reactor Institute of Kyoto University, JAPAN
[SATTA Naoya] firstname.lastname@example.org
To observe the leaching property and its change in valence from the soil intentionally polluted with pentavalent antimony (KSb(OH)6), extraction tests were performed with pure water and 1M hydrochloric acid (HCl). It was showed that the antimonate was sorbed by soil gradually and strongly, changed their form into insoluble with pure water. After three months from the pollution, extracted fractions of Sb were decreased to 10 % in pure water and increased to 40 % in 1M HCl, respectively. Sb concentrations in pure water leachate were three orders of magnitude lower than solubility of KSb(OH)6. Irrespective of leaching solution and initial soil moisture, Sb(V) was the predominant species in soluble fractions.
The results indicated that aging is one of effective factors on increasing 1M HCl soluble Sb(V) and decreasing water soluble Sb(V). Initial soil moisture influenced on extractabilities of these two solutions.
Heavy Metal Runoff from a Low Farm Block on the Coastal Creek Area of Ariake Bay in Japan
HAMADA Koji*, YOSHINAGA Ikuo**, HITOMI Tadayoshi*, MIURA Asa*, TAKAKI Kyoji*
* National Institute for Rural Engineering, Japan
** National Agricultural Research Center for Kyushu Okinawa Region, Japan
Runoff of heavy metals from farmland was examined based on field measurements conducted between June 15 and July 13, 2006. The study field is located in a lowland area where irrigation water was contaminated with water drained from upstream farmlands (recycling of water in irrigation). The area of the farmland is 11.2 ha, of which 6.0 ha and 4.5 ha have been used for rice and soybeans, respectively. The concentrations of heavy metals met the environmental standards, even though the values fluctuated owing to rainfall and farming activities. An increase in the runoff of heavy metals was observed during rainfall events and the paddling period, and in particular, the measured heavy metal runoff caused by rainfall was more than 10 times higher than in periods when there was no rain.
Biotransformations of arsenic species in activated sludge process
ANDRIANISA Harinaivo*, ITO Ayumi**, SASAKI Atsushi***, IKEDA Masaaki*,
AIZAWA Jiro* and UMITA Teruyuki**
*: Department of Civil and Environmental Engineering, Iwate University, JAPAN.
**: Department of Frontier Materials and Functional Engineering, Iwate University, JAPAN.
**: Technical Division of Instrumental Analysis, Faculty of Engineering, Yamagata University, JAPAN.
In this study, the kinetics of arsenite [As(III)] oxidation and arsenate [As(V)] reduction by activated sludge were investigated by laboratory experiments. The initial reaction rate data were fitted to the Michaelis-Menten model. Then, in order to confirm the potential application of activated sludge as As bio-oxidant, As speciation analysis was carried out for wastewater samples collected from 11 stations in the Akiu-Onsen Wastewater Treatment Plant (AWTP), located in Sendai, Japan, which is operated under the oxidation ditch activated sludge process. As(III) and As(V) were the dissolved species found in the influent and were similarly distributed. In the oxidation ditch, As(III) was oxidised to As(V) after supply of oxygen by the aerator and As(V) was the main species in the final effluent (>98% of total species). In the return sludge pipe, As(V) was reduced to As(III). As was inefficiently removed by the process and the final effluent concentration was 260 µg/L. By jar-tests, it was confirmed that addition of 24 mg/L as ferric chloride to the AWTP effluent could remove more than 95% of the biologically oxidised As and decreased the residual total As concentration to less than 10 µg/L..
It was concluded that the activated sludge process is a reliable technology to biologically oxidise As(III) to As(V) prior to an additional treatment, such as coagulation process, to remove As from contaminated wastewaters.
A study on arsenic removal monitoring from groundwater in Bangladesh using “guava method”
WANG Bo*, KITAWAKI Hidetoshi**, RAHMAN Md.mafizur***
*:Graduate School of Regional Development Studies, Toyo University, JAPAN **:Department of Regional Development Studies, Toyo University, JAPAN ***:Department of Civil Engineering, Bangladesh University of Engineering and Technology, BANGLADESH
[WANG Bo] email@example.com
[KITAWAKI Hidetoshi] firstname.lastname@example.org
Arsenic removal monitoring method, "Guava Method", through the removal of iron in groundwater, was developed using guava leaves and transparency meter. Field surveys were carried out in arsenic affected rural area in Bangladesh to identify the present situation of arsenic contamination which causes health problems. Groundwater quality was analyzed to identify the relationship between arsenic concentration and depth of tube wells. Sociological survey was also carried out to identify villagers' attitudes towards arsenic contamination, willingness-to-pay for arsenic removal equipments. Demonstration of "Guava Method" to villagers to show their willingness-to-pay increased because of the visible change in the water color.
Properties of Particles Sampled at High Temperatures in An Ash-Melting Furnace Stack
TAKAOKA Masaki*, SHIOTA Kenji*, MASUI Megumi**, TAKAHASHI Masamitsu***, SHISHIDA Ken-ichi****, TANAKA Tomoyuki+, TOMITA Yasuhiro++, ISHIYAMA Takahiro+++, TAKEDA Nobuo++++
*:Dept. of Urban & Environmental Engineering, Kyoto University
***:Kobelco Eco-Solutions Co. Ltd.
****:Takuma Co. Ltd.
+:Hitachi Zosen Corporation
++:Mitsui Engineering & Shipbuilding Co. Ltd.
+++:Japan Waste Research Foundation
++++:Eco-technology Research Center, Ritsumeikan University
[TAKAOKA Masaki] email@example.com
Heavy metals need to be concentrated as much as possible in order to recover them from melting furnace fly ash (MFA). Therefore, the particle sizes in MFA were investigated in this study. An in-stack cascade impactor was used to sample the MFA in a high temperature stack of the ash-melting furnace. The chemical composition and morphology of the particles were examined. Most of the MFA contained fine particles that were less than 10 μm in diameter and consisted primarily of Na, K, and Cl. Particles greater than 10 μm in diameter were non-spherical in shape and consisted primarily of carry-over components such as Si and Al. The concentration of Zn increased as the particle size of the MFA became smaller. A TEM analysis of the finer particles indicated that the chloride and the oxide components were dispersed.
Evaluation of Carbonation Treatment of Cement-solidified Municipal Solid Waste Incineration Fly Ash by Diffusion Test
Satoshi MIZUTANI*, Masaya UEMURA*, Takao YAMADA* and Yoshinori KANJO*
*Dept. of Urban Engineering, Osaka City University, JAPAN
[Satoshi MIZUTANI] firstname.lastname@example.org
Cement solidified municipal solid waste incineration fly ash are carbonated and the leaching behavior of Na, Pb and Zn are studied. The carbonation proceeded in proportion to the carbonated time. Carbonation reduced about 10 % of the void of the material. Diffusion test are performed and diffusive coefficient of Na, Pb and Zn are determined. Based on the differnces of diffusion coefficient of each element, influences of physical retention factors and chemical retention factors are discussed. Carbonation raises the physical retention factor. On the other hand, the treatment lowers the chemical retention factor for Pb and Zn. The overall diffusion coefficients of Pb decrease because the physical retention is bigger than chemical retention. However, diffusion coefficients of Zn increase because of the decrease of chemical retention effects.
Effectiveness as an Alternative Soil of the Waste Tile
Atsushi KAMIYA*, Minoru YONEDA*, Takashi ARAI**
*:Dept. of Urban and Environmental Engineering, Kyoto University,JAPAN
[KAMIYA Atsushi ] email@example.com
To see effectiveness as an alternative soil as a method of recycling the waste tile, the change in the water penetration and free volume, the amount of the effective moisture maintenance, and the effective fertilizer element keeping ability were examined. As a result, it has been understood that the change in the water penetration and the free volume are much smaller than that of mountain sand. Moreover, the keeping characteristic of the fertilizer showed a good result in the crushed tile of the particle size 2mm or less compared with mountain sand, pumice stone, activated carbon. In addition, the growth levels of the lawn were actually compared between in the cases of using crushed tiles and using mountain sand in a putter golf course. The results showed that the length of the root was about the twice long, and about twice larger the amount of chlorophyl a in the case of using crushed tile. It is thought that the crushed tile is extremely effective as an alternative soil for the lawn promotion.
Composition share of MSW slag in abrasion dust from asphalt concrete that contains MSW slag as aggregates
TAKAHASHI Fumitake*, KIDA Akiko**, SHIMAOKA Takayuki*
* Dept. of Urban and Environmental Engineering, Graduate School of Engineering, Kyushu University, JAPAN
** Research Center for Material Cycles and Waste Management, National Institute for Environmental Studies, JAPAN
[TAKAHASHI Fumitake] firstname.lastname@example.org
[KIDA Akiko] email@example.com
[SHIMAOKA Takayuki] firstname.lastname@example.org
Composition share of municipal solid waste (MSW) slag in abrasion dust from asphalt concrete, which consists of natural aggregates, MSW slag and asphalt binder, was estimated by two methods. One method is based on different intensities of X-ray diffraction for quartz between natural aggregates and MSW slag. The other is based on different concentration of heavy metals among these materials. In the case of fine abrasion dust whose diameter was less than 75 µm, both methods estimated that composition share of slag-derived material in the dust is nearly equal or less than that of slag in asphalt concreat . In contrast, opposite results were estimated by boths methods for 150 µm to 1.0 mm abrasion dust. This results suggested that MSW slag used in asphalt concrete seemed to be relatively hard to be milled finely compared to natural aggregates.
Swelling and strength properties of water swelling material used in containment facilities at waste landfill sites
INAZUMI Shinya*, WAKATSUKI Tadashi**, KOBAYASHI Masakatsu**, KIMURA Makoto***
*: Dept. of Urban Management, Grad. Sch. of Engineering, Kyoto University, JAPAN
**: Association for H-jointed SPSPs Methods, JAPAN
***: Innovative Collaboration Center, Kyoto University, JAPAN
[INAZUMI Shinya] email@example.com
A water swelling material is one of the rubbery impermeable materials which mixed synthetic resin elastomers as a base material, high absorbency polymers, filler and solvents. In this study, swelling and strength characteristics of water swelling material on their composition, long-term performance of water swelling material as an impermeable material at coastal waste landfill site, are examined by various laboratory experiments. The adjustment of resin content of the synthetic resin elastomer and degree of the etherification of the high absorption polymer contribute to the improvement in swelling and strength characteristics of the water swelling material. The strength of the water swelling material shows the tendency which is stabilized with the progress in the time, and it has the sufficient withstanding pressure at coastal waste landfill site that the application is considered as an impermeable material.
Fermentation for different type of L-lactate and synthesis of polylactate
TSUNO Hiroshi*, AKAO Satoshi**, MIYAI Kotaro*, HIDAKA Taira* and HORIE Taku*
*: Dept. of Urban and Environmental Engineering, Kyoto University, Japan
**: Dept. of Social Systems Engineering, Tottori University, Japan
[TSUNO Hiroshi] firstname.lastname@example.org
A fermentation technology to produce ammonium, sodium and calcium L-lactate with high optical purity from unsterilized garbage under 55℃ and pH 5.5 was developed by using ammonia, NaOH and Ca(OH)2 solutions, respectively, for pH adjustment in pH control. L-lactate fermentation speed with ammonia and Ca(OH)2 solutions was higher than that with NaOH. Lactate-ester was obtained from only lactate fermentation product with ammoniua solution in the refinery process of L-lactate through butyl lactate. And about 24 g of refined L-lactate was collected from 1.2 L of fermented liquid containing 36.7 g of L-lactate. From 23 g of the refined L-lactate, 3 g of poly lactic acid could be synthesized through 8 g of refined L, L-lactide.
Practicality of a High Value-Added Edible Mushroom (Eringi, Pleurotus eryngii) Using Sweet Potato Shochu Lees
Masahito YAMAUCHI*, Ryuichi IMAYA**, Masayoshi YAMADA***,Sumio MASUDA****,
Masato KIHARA*, Kenjiro YONEYAMA***** and Hideki HARADA******
*:Dept.of Civil Engineering, Kagoshima National College of Technology
**:Uemura Co. Ltd.
***:Dept.of Environmental Systems Engineering, Nagaoka University of Technology
****:Dept. of Civil and Environmental Engineering, Miyazaki University
*****:Xenocross Co. Ltd.
******:Dept. of Civil Engineering, Tohoku University
The solid fraction of shochu lees emitted from shochu production is dried and used effectively as a livestock feed and a fertilizer. In this study, we took note that shochu lees are a byproduct derived from agricultural produce and safe industrial food waste with high nutritional value, developed a mushroom bed made from the dried solid of sweet potato shochu lees (dried solid of shochu lees, hereafter), and ran a mushroom (eringi, Pleurotus eryingii) culture test. The dried solid of shochu lees cut culture time and improved the yield and quality of the fruiting body; it was found suitable as a nutritional material for mushroom culture. Especially in a test plot with the shochu lees added at 60%, the culture time was about five days shorter and the yield of the fruiting body 60% greater than in a test plot with a control medium (BL) containing rice bran and wheat bran as nutritional materials. Moreover, eringi cultured with the dried solid of shochu lees was tastier, sweeter, and better in texture than eringi grown with the control medium.
The dried solid of shochu lees used as a nutritional material was also indicated to be economical in that it reduced material cost to three to four fifths that of conventional media.
As described above, eringi culture using the dried solid of shochu lees is less costly and more effective for improving the yield and quality. Therefore, it is considered practically applicable.
Effects of Johkaso Sludge on the Operation of Night-soil Treatment Plants based on a Questionnaire Survey to Plant Operatios Managers
Hidenori HARADA*, **, Tomonari MATSUDA*, Saburo MATSUI*
*Graduate School of Global Environmental Studies, Kyoto Univerisity, **Research Fellow, Japan Society for the Promotion of Science
[Hidenori HARADA] email@example.com
[Tomonari MATSUDA] firstname.lastname@example.org
[Saburo MATSUI] email@example.com
Night-soil treatment system has still played the crucial role as a wastewater treatment system in Japan. Recently, the plants are facing the change of treated objectives characteristics. One of the main reason of its change may be the increasing volume ratio of Johkasou sludge among total treated objectives. Aiming at the betterment of night-soil treatment system management, we investigated the effects of Johkasou sludge on the operation of night-soil treatment plants based on a questionnaire survey to the plant operations managers. The results indicated that a large number of the prolems during plant operation were derived from Johkasou sludge, of which characteristics varied more widely than excreta and which contained fatty oil and decaied sludge. Also, it was suggested that Johkasou-sludge adaptive treatment plants could not give a satisfactory solution for this probleme. A primary meaure against such problems was to alleviate the negative effect of Johkaso sludge by mixing with excreta. Other fundamental measures, however, may be required, considering the increasing volume ratio of Johkaso sludge and reducing that of excreta in near future.
Usability of quinone biomarker as a stability index of final landfill sites for municipal solid waste
Masafumi FUJITA*, Kentaro IMAI*, Koji TSUJI*, Yasushi SAKAMOTO*
*:Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi
[FUJITA Masafumi] firstname.lastname@example.org
Usability of quinone biomarker as a stability index of final landfill sites for municipal solid waste was investigated through the observation of leachate collected from 7 sites which had 3-28 years history from the start of landfill. Microbial respiration tests for the determination of OUR and NUR were conducted, so that remarkable differences appeared in NUR/OUR ratio. Then, CODMn and TN of leachate were also used for the categolization of 7 sites. Consequently, 5 sites which showed lower NUR/OUR ratio were categorized into 2 groups. In other words, according to the progress of stability, 7 sites were categorized into 3 groups. Meanwhile, MDS analysis was conducted by use of quinone profile of leachate. The position of the respective sites on MDS map converged according to the categorization previously determined. Therefore, quinone biomaker was probably useful as the stability index. Moreover, it was also found that Q-8 and Q-9 containing bacteria had an important role in the progress of stability.
Collection system for compost from composting toilet in slum area of Bandung
USHIJIMA Ken*, IRIE Mitsuteru**, SINTAWARDANI Neni***, TRIASTUTI Jovita*** and ISHIKAWA Tadaharu****
*Water Quality Research Division, Water Resrources Environment Technology Center, JAPAN
**Alliance for Research on North Africa, University of Tsukuba, JAPAN
***Research Centre for Physics, Indonesian Institute of Sciences, INDONASIA
****Graduate School of Science and Engineering, Tokyo Institute of Technology, JAPAN
[USHIJIMA Ken] email@example.com
Composting toilet system seems one of alternative toilet under the condition without sewerage system, such as slum area. Residue from composting toilet is available as a compost, however collection and transportation system for compost have to be prepared especially in heavily populated slum area. To discuss feasibility of composting toilet system in slum area, these parts seems quite important. But collecting system or transporting system for toilet compost has not been discussed. In this article, we designed possible collection system model based on field survey data, and evaluated its feasibility. Framework of collection system is designed with referring present garbage collection system, because any practical example is not exist even in Japan. According to estimation with this model, combined treatment and collection for garbage and excrement compost can be work with roughly same capacity of present garbage collection. The system seemed to have enough feasibility.
Influence of surface water discharge from a reservoir on an outbreak of blue-green algae bloom
KITAZAWA Hiroyoshi*,**, TOMINAGA Kazuki**, KITADA Shingo**, SAITO Shigeru**, SATO Chikafusa*,**, KOIZUMI Akira*
*:Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, JAPAN
**:Bureau of Waterworks Tokyo Metropolitan Government, JAPAN
[KITAZAWA Hiroyoshi] firstname.lastname@example.org
In the Ogochi Reservoir, one of Japan’s largest reservoirs used exclusively for supplying water, after 1990, every year algae bloom is caused by the excessive growth of blue-green algae, such as Microcystis and Anabaena, and its scale and duration are expanding. In a notable change in reservoir management after 1990, a spout from the dam was changed and, since 1992, surface water was discharged from April to November as a measure against cold water. We therefore investigated outbreaks of blue-green algae bloom on the basis of our previous data, and analyzed relations of surface discharge to bloom. Consequently, we discovered that a rise in surface water temperature, caused by surface discharge during summer, would promote the growth of bloom-forming blue-green algae which preferred higher temperatures. We also concluded that the discharge from the upper spout made the depth of the secondary thermocline shallow, so that the nutrient supply to the productive zone of the reservoir would increase and bloom-forming blue-green algae would easily grow.
Investigation of water-bloom control effect in Urushizawa dam reservoir
NOMURA Munehiro*, SATO Hironobu*, SHITARA Kazuhiko*, TSUBONE Fumiyoshi*, CHIBA Nobuo*, FUJIMOTO Naoshi**, NAKANO Kazunori*, NISHIMURA Osamu*
*:Graduate school of Engineering, Tohoku University, JAPAN
**:Graduate school of Agriculture, Tokyo University of Agriculture, JAPAN
[NOMURA Munehiro] email@example.com
Field survey has been carried out to investigate the water-bloom control effect based on characteristics of water quality stratification in Urushizawa dam reservoir without the pollutant load source in the basin. Water quality prediction model which could reproduce stratification and fluctuation of Chl.a approximately was able to be constructed by considering inflow of the river water and intake of the dam water. As a result of examining the intake method, it was found that Chl.a might be increased by supplying nutrient from the lower layer to the surface, though to decrease Chl.a by intake of surface water was effective.
Growth Inhibition of Microycstis aeruginosa and Associated Release of Intraellular Microcystin by UV irradiation
Hiroshi SAKAI*, Hiroyuki KATAYAMA*, Kumiko OGUMA* and Shinichiro OHGAKI*
*: Dept. of Urban Engineering, The University of Tokyo
[Hiroshi SAKAI] firstname.lastname@example.org [Shinichiro OHGAKI] email@example.com
Microcystis aeruginosa, a toxic cyanobacteria, hardly grows on solidified media. Therefore, it was difficult to evaluate the growth inhibitory effect by UV irradiation on Microcystis aeruginosa appropriately. This study develoed a new incubation method to determine the number of cells with reproduction ability. About 2 log of growth inhibition was observed after UV irradiation at the fluence of 120-180 mJ/cm2. No increase of growth inhibitory effect was observed with UV irradiation at the fluence of more than 180 mJ/cm2. Released microcystin per dead cell at the UV fluence of 120-180 mJ/cm2 was almost same as the intracellular microcystin amount per cell before UV irradiation. The released microcystin amount was reduced by UV irradiation at the fluence of over 600 mJ/cm2, which was probably due to the decomposition of intracellular microcystin by UV.
A Trial to Estimate the Trapping Ratio of Silica in Dam Reservoirs by Diatom
Kunihiko AMANO* and Toshikazu TOKIOKA**
*River Restoration Team, Water Environmnet Group, Public Works Research Institute
**International Cooperation Team, Water Hazard Group, Public Works Research Institute
[Kunihiko AMANO] firstname.lastname@example.org
We tried to estimate the amount of silica trapped by diatoms in dam reservoirs in Japan. For this purpose, we have measured the concentration of biogenic silica in bottom sediments and settling flux of biogenic silica due to the uptake of diatoms in a dam reservoir. We have also conducted simulation analysis to estimate the settling flux of biogenic silica due to the uptake of diatoms. Followings are found by this trial.
1) Simulation analysis showed that the ratio of silica that is uptaken by diatoms and sunk in dam reservoirs is less than 1 % comparing to the inflow flux. Based on this result, the magnitude of trapping of silica by diatoms in dam reservoirs in Japan does not seem significant.
2) Field experimental results implied the settling velocity of diatoms is about 0.04 – 0.06 m/d, suggesting that trap of silica by diatoms is not significant.
3) Augmentation of nutrients and increase of retention time in reservoirs will increase the trapping ratio of silica by diatom growth.
A sturdy of Environmental effecters on larval recruitment of Musculista senhousia in Hakata Bay
Koreyoshi YAMASAKI*, Ryouich WATANABE*, Yoshinori KITANO**, Hiroshi KUMAGAI***
*Department of Civil Engineering, Faculty of Engineering ,Fukuoka University
*Facukty of Engineering, Kantou Gakuin University
*Fukuoka Institute of Health and Environmental Sciences
We studied the larval recruitment and the cohort density of Musculista senhousia(MS) which is abundant and highly consumes DO at the bottom of Hakata bay. We proposed the recruitment potential as the max population of MS appeared in study period, and found that the potential is affected by mean benthic ignition loss and mean AVS throughout the period. We also show that each recruitment is affected by DO and AVS at each recruitment season.
Effect of decreasing current velocity on new settling of planktonic bivalve larvae by laver culture nets
HIWATARI Takehiko*, MORI Shoichi**, HIGASHI Hironori*, MURAKAMI Shogo*, DEGUCHI Ichiro***, KOHATA Kunio*
*:National Institute for Environmental Studies, JAPAN
**:Mori Institute of Ecology CO., LTD., JAPAN
***:Department of Civil Engineering, Osaka University, JAPAN
[HIWATARI Takehiko] email@example.com
Field experiments by using laver culture nets were carried out to evaluate the effect of decreasing current velocity on new settling of planktonic bivalve larvae at a coast of Matsuzaka. The current velocity of the area of setting nets corresponding to that of the control area, without setting nets, were decreased due to attaching a high density of seaweed on the nets. The new settlers density of the area of the setting nets were always higher than that of the control area, which indicate that the new settling of the planktonic larvae was accelerated due to decreasing current velocity. Temporal shell length variations (200-300μm) including the new settlers length collected as the planktonic larvae in the seawater indicate that the new settlers are moved and re-suspended due to a strong wave action.
Possibility of environmental improvement by revival of oyster farming in Ariake Bay
Hiroki OGAWA*, Hiroki IYOOKA**, Kenji SUSHIMOTO***, Tetsuya KUSUDA**
* Department of Civil Engineering, Kyushu University, JAPAN
** Department of Civil Engineering, Kyushu University, JAPAN
*** Mikuniya Corporation, JAPAN
[Hiroki OGAWA] firstname.lastname@example.org
Possibility of the environmental improvement useing oyster farming in Ariake Bay was examined. Analysis using a BOX model considering physiology of oyster that inhabits Ariake Bay was carried out. Physiologic characteristics of oyster were observed through experiments using oysters collected in Ariake Bay. The equasions of filtration, assimilation and respiration were established with good precision. The model calculated the quantities of phytoplankton that was decreased by filtering and nutrients (nitrogen and phosphorus) removed by catching of oyster. That is to say, oyster farming in Ariake Bay shows enough encironmental improvement effects. Oyster catch of 18,000ton (the highest oyster catch at Ariake Bay in the past) was removes 360t of nitorogen and 20t of phosphorus and make about 80 percent reduction in phytoplankton in August. The effect on pytoplankton decrease is well in summer, the season of red tides and in winter, the season of Nori laver farming. As the result, the oyster farming is effecteve for the prevention of red tide in summer and enriches the nutrient environment for Nori laver in winter.
Study on control of SRB's activity by a proper oxygen introduction in anaerobic biological wastewater treatment systems.
INO Toshihito, WANG Xinhai, IMAI Tsuyoshi, ARAKANE Mitsuhiro, HIGUCHI Takaya, SEKINE Masahiko
Graduate School of Science and Engineering, Yamaguchi University
[Tsuyoshi IMAI] email@example.com
In the anaerobic wastewater treatment process, methane is produced and used due to it's served as high energy and low impact to the environment. However, inhibitory to methane producing bacteria (MPB) were occurred in case of presenting of large amount of sulfate reducing bacteria (SRB) in treatment process and caused of reduction of methane production potential. For the countermeasure to SRB, Nitrogen gas was used as stripping gas for removal of H2S produced by SRB. The results indicate that introduction of Nitrogen could remove the inhibition of H2S effectively and the production of methane gas was increased. Other effects are the control of SRB's activity by difference of Oxygen tolerance and oxidizing effect of hydrogen sulfide. The results indicate that these effects by oxygen introduction to anaerobic reactor were able to collect a stable methane.
Evaluation of process of the Expanded Granular Sludge Bed (EGSB) reactor for performance treatment of municipal sewage
Masahiro OKAWARA*, Keita NISHIYAMA*, Takashi YAMAGUCHI*
Kazuaki SYUTSUBO**, Hiroyuki IMACHI***, Hideki HARADA**** and Akiyoshi OHASHI*****
*:Dept. of Environmental Engineering , Nagaoka University of Technology
**:Water and Soil Environment Division , National Institute for Environmental Studies
***:Extremobiosphere Rsearch Center,Japan Agency for Marin-Earth Science and Technology (JAMSTEC)
****:Dept. of Civil and Environmental Engineering , Tohoku University
*****:Dept. of Social and Environmental Engineering , Hirosima University
In this study, Expanded Granular Sludge Bed (EGSB) reactor, inoculated with mesophilic granular sludge, was applied to the treatment of municipal sewage, in order to investigate the process reliability. The EGSB reactor was operated at ambient temperature (9℃~27℃) for over 500 days with HRT of 2 hours, average OLR at 4.1 kgCOD・m-3・day-1 and 6 m・h-1 of up-flow velocity. Suspended solid (SS)-COD removal efficiency showed an fluctuation due to the high upflow velocity by effluent recirculation in EGSB reactor, and influent sewage was not treated by primary-sedimentation. Consequently, the preliminary sedimentation tank had been installed just prior to inlet of the EGSB reactor and able to obtain the stability of influent SS concentration. As the result, the CODcr removal rate at HRT of 2 hours was maintained at 44% without any effects of inconstant ambient temperature. The decline of the temperature of sewage caused the decreace of the acvity and amount of retained sludge. However, it is possible to retaine the one-third of granular sludge from initial amounts after 500 days operation.
The Effect of Shock Loading to the Performance of Thermophilic UASB reactor in terms of Deterioration and Recovery
Eisuke TAMURA*, Taketoshi NAKAMURA*, Masaaki KAWASHIMA*,
Narin PATTANANUWAT*, Takashi YAMAGUCHI*,
Hiroyuki IMACHI**, Hideki HARADA*** and Akiyoshi OHASHI****
*:Dept. of Environmental System Engineering, Nagaoka University of Technology **:Japan Agency for Marine-Earth Science and Technology Research Scientist Extremobiosphere Research Center ***:Dept. of Civil Engineering, Tohoku University ****:Dept. of Social and Environmental Engineering, Hiroshima University
[Eisuke TAMURA] firstname.lastname@example.org
Since thermophilic UASB reactor is vulnerable to environmental variations, it has been widely reported that the treatment process could be easily deteriorated by the accumulation of propionic acid. However, the process of both deterioration and recovery derived from the accumulation has not yet been satisfactorily studied in details. To achieve the aim of elucidating the deterioration process, thermophilic UASB reactor has been conducted to study the performance before and after shock loadings in terms of effluent and biogas analysis. The analysis of the results indicates at 10 times of shock loading, even VFA accumulated but if pH was maintained at the regular level, the treatment process can be restored immediately. On the other hand, when pH dropped below an appropriate level, if shock loading period continues longer, the recovery rate will also be relatively extended. For example, it would take 17 days of recovery due to 3 days of shock loading. The experiment demonstrated that the VFA accumulation was not the direct cause of the process deterioration but indirectly decreasing in pH level could severely damage the microorganisms more in numbers.
Accumulation of Sulfur Granules in the Denitrification Reactor with Autotrophic and Heterotrophic Denitrification Bacteria
Ryoko YAMAMOTO-IKEMOTO1, Takahiro YAMASHITA1 and Erika KANEKO
Graduate School of Natural Science and Technology, Kanazawa University
Sulfur accumulation in the sulfate reduction-sulfur denitrification process was examined using the laboratory scale biological filter reactors. In the sulfate-reducing reactor, sulfide and acetate were produced by sulfate reducing bacteria. In the denitrification reactor, sulfur denitrification and heterotrophic denitrification occurred simultaneously. When the S/N ratio was over 1.0, about 50% of utilized sulfide was oxidized to sulfur granules and the granules were accumulated in the reactor. Nitrate was utilized for sulfur denitrification predominantly, and remained nitrate was utilized for heterotrophic denitrification. When the S/N ratio decreased under 0.5, sulfur granules accumulated in the reactor were oxidized to sulfate. The sulfur oxidation-reduction cycle was established in the denitrification reactor.
Response of bacterial community and hydrogen productivity to carbon-nitrogen balance in continuous methophilic hydrogen fermentation
Yasunori KAWAGOSHI*, Naoe HINO**, Masaharu NAKAO*, Aya Fujimoto*, Kenji FURUKAWA*
* : Graduate School of Science & Technology, Kumamoto University
** : Technical research institute, Hitachi Zosen Corporation
[KAWAGOSHI Yasunori] email@example.com
Effect of a carbon-nitrogen balance on hydrogen (H2) production and bacterial community in continuous mesophilic hydrogen fermentation was invesigated. The highest H2 production yield was obtained when the C/N ratio was 36, and it was indicated that Clostridium species mainly contributed to the H2 production. The H2 productivity was decreased and lactic acid bacteria became dominant at high C/N ratio (lack of nitrogen) condition, but H2 productivity was rapidly recovered by a control of C/N balance through the bacterial community change. The H2 production was also decreased when C/N ratio was lower than 36 (excess of nitrogen), and bacterial community shifted within genus Clostridium. In this case, the recovery of H2 productivity and bacterial community were also possible, but these are slower than above case. These results indicated that 1) The carbon-nitrogen balance affects on both the H2 productivity and bacterial community., 2) Change of bacterial community is reversible., 3) Hydrogen fermentating bacteria and lactic acid bacteria are competitive., 4) The competition within the bacteria of same genus Clostridium, which are hydrogen fermentating bacteria, are also competitive, and affects on hydrogen productivity.
Changes in structure and functions of microbial community in soil by introduction of plasmid-harboring bacteria
INOUE Daisuke*, TSUTSUI Hirofumi*, YAMAZAKI Yuji*, MURASHIGE Katsushi*, SEI Kazunari*, SODA Satoshi*, FUJITA Masanori*,**, IKE Michihiko*
*:Division of Sustainable Energy and Environmental Engineering, Osaka University, JAPAN
**:Kochi National College of Technology, JAPAN
[INOUE Daisuke] firstname.lastname@example.org
In bioaugmentation of contaminated environments, assessment of bio-risks associated with the environmental release of exogenous bacteria is needed. In this study, soil microcosm experiments were carried out to analyze the changes in the structure and metabolic functions of indigenous microbial community by introduction of exogenous bacteria with and without self-transmissible and mobilizable plasmids. The introduction of the exogenous bacteria transiently disturbed the microbial community structure. However, the adverse effect lessened with the decrease in the exogenous populations. In addition, disturbance of the microbial metabolic functions by the introduction of exogenous bacteria was not detected throughout the experimental period. Transconjugants, which were formed by conjugative plasmid transfer from the exogenous bacteria to the indigenous bacteria, were temporarily detected when the exogenous bacteria harboring the self-transmissible plasmid were introduced into the microcosm. The occurrence of the transconjugants did not have any apparent effect on the structure and functions of the microbial community. These results suggest that if the exogenous bacteria and the transconjugants do not survive in the environment, the effects of the introduction of the exogenous bacteria on the indigenous microbial community (bio-risks) do not persist for a long time.
Microbial Community Analysis in Thermophilic Methane Fermenters of Kitchen Waste
CHEON Jihoon*, HIDAKA Taira*, HONG Feng*, KOSHIKAWA Hiromoto**, IWASAKI Daisuke***, and TSUNO Hiroshi*
*: Dept. of Urban and Environmental Engineering, Kyoto University, Japan
**: Dept. of Environmental Solution Technology, Ryukoku University, Japan
***: Sewerage Engineering Dept., Takuma Co. Ltd., Japan
[HIDAKA Taira] email@example.com
Microbial community in a thermophilic lab-scale methane digester and a full-scale methane digester for treatment of kitchen waste were analysed by random clone method. The lab-scale reactor was continuously operated with increasing organic loading ratio from 20.5 to 35.9 kgCOD/(m3∙d). The most detected clone was closely related to Bacillus infernus. Methanoculleus thermophilus and Methanothermobacter wolfeii were the most detected Archaea. Propionate concentrations increased twice during the operation, and simultaneously the B. infernus occupying ratio also increased to 59 %. Increasing tendency of B. infernus occupying ratio can be used as a sign of propionate accumulation. The full-scale reactor was innoculated with digested sludge from a sewage treatment plant. After continuously operated with kitchen waste, the microbial diversity became similar to that in the lab-scale reactor fed with the artificial kitchen waste. These results proved the applicability of microbial diversity analysis to discuss the reactor operation.
Development of Fluorescence in-situ Hybridization for Targeting apsA mRNA in Sulfate Reducing Bacteria
Yuki OHTSUKA*, Naoto HASHIMOTO*, Nobuo ARAKI*, Kenichi ABE**, Shuji KAWAKAMI**, Takashi YAMAGUCHI**, Kazuaki SYUTSUBO***
*Dept. of Civil Engineering, Nagaoka National College of Technology, JAPAN
**Dept. of Environmental System Engineering, Nagaoka University of Technology, JAPAN
***Watev and Soil Environmental Division, National Institute for Environmental Studies, JAPAN
[Nobuo ARAKI] firstname.lastname@example.org
Fluorescence in situ hybridization (FISH) of intracellular mRNA in sulfate reducing bacteria was carried out with high sensitive detection systems such as tyramide signal amplification (TSA) and two-pass TSA. In addition Oligonucleotide probes of APS8R and SRB385 were used for detecting adenosine-5'-phosphosulfate (APS) reductase gene (apsA) mRNA transcripts and 16S rRNA, respectively, derived from sulfate reducing bacteria. Desulfovibrio vulgaris, a model sulfate reducing bacterium, was chosen to refine the protocol. Specificity of APS8R and optimal hybridization stringency were tested with expression clones. To inhibit endogenous peroxidases, sludge sample taken from an UASB reactor was treated 30 min with 5% of hydrogen peroxide in methanol. The sample was also incubated 30min in 1 mg/mL lisozyme solution at 37˚C for optimal cell permeabilization. Addition of dextran sulphate and blocking reagent to buffer solution in TSA step greatly enhanced fluorescence signal intensity of mRNA FISH. TSA-FISH was the more appropriate for visualizing apsA mRNA in sulfate reducing bacteria in the sludge sample.
Evaluation of Temporal Moment Variation in Space for Estimating NAPL Pool
INOUE Kazuya*, MASAKI Ippei**, SUZUKI Fumiyo***, TANAKA Tsutomu*
*Graduate School of Agricultural Science, Kobe University,
**Nihon Suido Consultants Co., Ltd.
***Graduate School of Science and Technology, Kobe University
[INOUE Kazuya] email@example.com
In this paper, the method of temporal moment (MOM) formulae is applied to analyze breakthrough data from a laboratory miscible displacement experiments of sodium chloride as a conservative tracer and to investigate the influence of the magnitude of entrapped nonaqueous phase liquid (NAPL) to the spatial variation of one-, two- and three-temporal moments at observation points in a horizontally placed flow field filled with silica sand. The results reveal that breakthrough curves measured at downstream side of NAPL pool reflect the evidence of NAPL pool existence through a comparison with the results obtained under the homogeneous flow condition while change of temporal moments in a region where transverse dispersion affects a time series of concentration data shows the magnitude of NAPL pool. Integrated evaluation of temporal moment variation in space associated with the variation ratio according to a monitoring location suggests that the MOM has a potential to provide an additional useful means of the estimation for NAPL source location and the quantity of NAPL present.
The validity of default value of daily soil ingestion evaluated by the amount of soil on children's hands
IKEGAMI Maiko*, YONEDA Minoru*, MORISAWA Shinsuke*
*: Dept. of Urban and Environmental Engineering, Kyoto University, JAPAN
[IKEGAMI Maiko] firstname.lastname@example.org
[YONEDA Minoru] email@example.com
Brownfields are becoming serious problems now. In soil contamination countermeasures law, the soil content standard is calculated by using the amount of soil ingestion each day. This amount is set at 200mg/day in the case of children and 100mg/day adult. The amount of soil particulate was able to be estimated by wiping soil particulate on hands and measuring the amount of Al in some stuff with which wipe hands. The amount of the adhesion of soil on children's hands examined by wiping their hands after they played outside was 50mg, and the estimated value of ingestion of soil particulate from the atmosphere was 0.5mg. If these values are equal to ingestion of soil particulate, they were about a quarter of the amount of soil ingestion each day. This conclusion shows the validity of the amount of soil ingestion used in environmental quality standards for soil pollution.
Examination of fixing method of optimal sampling location using stochastic methods considering subjective information
Tomoyuki FUKUSHIMA*, Minoru YONEDA*, Shinsuke MORISAWA*, Osamu BANNAI*
*:Department of Arban and Environmental Engineering, Kyoto University, JAPAN
[Tomoyuki FUKUSHIMA] firstname.lastname@example.org
A new method of using subjective information was proposed on occasions when the arrangement of optimal sampling locations were selected for the survey of concentration distribution of soil pollutants in a target area. The hybrid algorithm that combined genetic algorithm with the steepest descent node method was used to explore the arrangement of optimal sampling locations. First of all, various evaluation functions were set, and then, their performances of fixing method of the optimal locations were compared using the Monte Carlo method. The evaluation function which had the highest estimation accuracy determined from the comparison was adopted to analyze the influences of increasing the number of samples in the Monte Carlo method and the effects of considering subjective information. The results showed that some evaluation functions with true subjective information gave better arrangement of sampling locations than lattice-like arrangement or optimal arrangement under the condition of no-prior information.
Development of the Phosphorus Recovery Process for Anaerobic Digested Sludge Using crystallization
Kazuaki SHIMAMURA* , Asei MIZUOKA* , Hideyuki ISHIKAWA* , Izumi HIRASAWA**
*Ebara Environmental Engineering Co., Ltd.
**Department of Applied Chemistry, Waseda University
Removal and recovery of phosphorous from swage in form of MAP (magnesium ammonium phosphate) have attracted attention from the view point of eutrophication prevention, phosphorus resource recovery. In this work, we conducted the basic investigations on the phosphorus recovery process for anaerobic digested sludge using crystallization, and the demonstration tests using a pilot scale and full-scale experimenral plant. A total-phosphorus recovery ratio higher than 30% was achieved, and a reacted soluble phosphorus recovery ratio higher than 95% was achieved. A case study in applying this phosphorus recovery process for treatment of sludge from an anaerobic-aerobic process of 21,000 m3/d sewage plant, evidenced that 30% of phosphorus concentration can be reduced in the final effluent and recovering 315 kg/d as MAP.
Improvement on anaerobic biodegradation of excess sludge by subcritical water process
ARAKANE Mitsuhiro*, IMAI Tsuyoshi*, YOSHIDA Kenichi**, HIGUCHI Takaya*, SEKINE Masahiko*, MURAKAMI Sadaaki***, TAKEUCHI Masami***
*:Graduate School of Science and Engineering, Yamaguchi University
**:Chugai Ro Corporation, Ltd.
***:Dept. of Chemical and Biological Engineering, Ube National College of Technology
[IMAI Tsuyoshi] email@example.com
Due to the large amount of excess sludge produced from treatment plants, sludge solubilization technology is introduced as excess sludge reducible technology. For solubilization processes, subcritical water process has become the center of attention for higher solubilizing rate characterization and easiness of resources recovery such as methane or phosphate. Beside 50-65% of TOC removal is due to the production of difficult biodegrade matter from subscritical water process. In this study, factor influences on solibilization process (temperature, alkali and acid additions) are carried out. As results, the suitable condition for methane recovery from excess sludge by subcritical water process is treating temperature at 150℃ and acid addition rate at 0.1-0.5 (g-HCl/g-TS).
Rheological Characterization of Mesophilic and Thermophilic Anaerobic Digestion Sludge
Mitsuharu TERASIMA*, Rajeev GOEL*, Kazuya KOMATSU*, Hidenari YASUI*, Hiroshi TAKAHASHI**, Li Yu-You. Y.***, Tatsuya NOIKE****
* Kurita Water industries Ltd.
** Graduate School of Environmental Studies, Tohoku University
*** Department of Civil Engineering, Tohoku University
**** Advanced research Institute, Nihon University
[Mitsuharu TERASIMA] firstname.lastname@example.org, [Rajeev GOEL] email@example.com, [Kazuya KOMATSU] firstname.lastname@example.org, [Hidenari YASUI] email@example.com, [Hiroshi TAKAHASHI] firstname.lastname@example.org, [Li Yu-You. Y.]
Rheological characteristics of anaerobically digested mesophilic and thermophilic sludge was studied using pipe-line pressure-drop measurement apparatus. Anaerobically digested mesophilic and thermophilic sludge samples were collected from anaerobic digesters operated at 35 °C and 55 °C respectively. Rheology of both the sludge was similar to pseudoplastic fluid and was modeled using power equation . The value of model parameters of pseudo-plastic viscosity (μp) and flow behavior index (n) were found to depend on sludge concentration (X). The empirical equations describing the relationship between sludge concentration and model parameters were μp=0.018e(0.071X) ; n=0.68e(-0.0069X) for thermophilic sludge and
μp=0.0095e(0.070X) ; n=0.66e(-0.0069X) for mesophilic sludge. The value of μp for thermophilic sludge was found to be significantly lower than mesophilic sludge. Reducing the temperature from 55 °C to 32 °C during viscosity measurement of thermophilic sludge resulted in a μp value, which was still lower than the mesophilic sludge. These observations suggest that the characteristic of solid in sludge is more influential than temperature in governing the sludge viscosity. The lower viscosity of thermophilic sludge can be used to operate high rate anaerobic digestion process at high solid concentration without additional energy input.
Sequential Removal of Phosphate and Heavy Metals from Sewage Sludge
by Applying Sulfur Cycle
Masanobu TAKASHIMA1 and Yoshihito TANAKA2
1Dept. for the Application of Nuclear Technology, Fukui University of Technology, Japan
2Technology Division, Hokukon Ltd., Japan
In this research, a sludge treatment system consisting of sulfate-added anaerobic digestion and bacteria leaching was constructed, and the sequential removal of phosphate and heavy metals from sewage sludge was examined. The sewage sludge used was ordinary one in Run 1 and chemical precipitation sludge artificially added with ferric phosphate in Run 2. Sulfate was added as sulfuric acid to the mesophilic anaerobic digesters at the level of either 0, 80 or 160 μL/d (0, 29-33 or 59-66 μL/g SS fed respectively) throughout this study. The average phosphate concentration obtained was about 110 mg/L in Run 1 (T-Pin 302 mg/L), and about 460 mg/L in Run 2 (T-Pin 855 mg/L) with the sulfuric acid addition of 160 μL/d. Then, the settled sludge from the anaerobic digesters was treated by bacteria leaching at 5 day HRT. It was estimated that about 91% of Zn and 43% of Cu were solubilized at its maximum. The above results indicate the capability of removing phosphate and heavy metals from sewage sludge by applying this proposed system.
Upgrading of the anaerobic digestion of waste activated sludge by conbining temperature-phased anaerobic digestion and intermediate ozonation
Takuro KOBAYASHI*, Yu-You LI*, Hideki HARADA*, Hidenari YASUI**
and Tatsuya NOIKE***
*Depertment of Civil and Eivironmental Engineering, Tohoku University, JAPAN
**KURITA Water Industries Ltd., JAPAN
***Advanced Research Institute for the Sciences and the Humanities, Nihon University, JAPAN
[Takuro KOBAYASHI] email@example.com [Yu-You LI] firstname.lastname@example.org
Upgrading of the anaerobic digestion of waste activated sludge (WAS) by the combination of temperature-phased two stage and intermediate ozonation was investigated by a continuous experiment with two processes, TM and TOM. The TM process is a temperature-phased two stage system which
consists of a thermophlic digester with 5 liters of volume and mesophilic digester with 5 liters of volume in series. The TOM process is a temperature-phased two stage process with the intermediate ozonation. Two processes were operated at a hydraoulic retention times of 30 days for over 123 days. Methane production rate, CODCr removal efficiency and dewaterability of TOM process were superior to those of TM process. It is the effect of temperature-phase that enhancing hydrolysis at thermophilic temperature and degradation of remaining soluble organic matters at mesophilic temperature, which leads to the improvement of dewaterability and decreasing CODCr in the supernatant effluent. The intermediate ozonation can save the ozone dose amount compared to the pretreatment and promote degradation of particle organic matters in the effluent from thermophilic reactor. The effects of the temperature-phase and the intermediate ozonation resulted in increasing CODCr removal efficiency of TOM process, 1.36 times higher than that of mesophilic anaerobic digestion.