In this study, a bio-electro reactor in which H₂ gas produced by electrolysis of water and organic matter were used for the reduction of nitrate was investigated. A mathematical model describing the utilization of both substrates in a biofilm attached on the surface of the cathode was developed. The following three phases were discussed;(1) The relation between distribution of substance concentration and denitrification rate inside of biofilm by using only electrolysis of water as electron donor supply.(2) The relation between distribution of substance concentration and denitrification rate inside of biofilm by using only acetate as electron donor supply.(3) The relation between distribution of substance concentration and denitrification rate inside of biofilm by using both of electrolysis of water and acetate as electron donor supply. The calculation results showed that the denitrification rate was significantly increased when H₂ gas and organic matter were used simultaneously. The model prediction and experimental results were in fairly good agreements.

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Due to an increased eutrophication of rivers and lakes, enhanced biological phosphorus removal (EBPR) process is now taken notice of. But the strategy of controlling EBPR process has not been established yet, because it is sometimes observed that the sludge suddenly loses the phosphorus removal activity. This is mainly because the bacteria which accumulate polyphosphate in the EBPR sludge have not been isolated, and because there is not enough information about the whole bacterial community in EBPR sludge.
Nowadays, new methods for analyzing microbial community such as molecular methods become available. In this study, the microbial community of EBPR sludge were characterized using the PCRDGGE (Polymerase chain reaction-Denaturing gradient gel electrophoresis) method.
Laboratory-scale sequencing batch reactor (SBR) was used, and the polyphosphate accumulating organisms (PAOs) were enriched using anaerobic aerobic configuration. The simple substrate which contained only acetate as a carbon source was fed. The microbial community was monitored usingthe PCR-DGGE method for about 2 months after the seed sludge was inoculated. The community gradually changed and got simple about lmonth later. The major bands on the DGGE gel were excised and the DNA recovered from them was sequenced. As a result, the bacteria that continued to increase during enrichment and became dominant at last were closely related to one of the putative PAO group which Crocetti et al.(2000) and Hesselmann et al (1999) have proposed. This PAO group is closely related to Rhodocyclus group (α Proteobacteria), but has no photosynthetic activity.

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Nitrification and denitrification process is a useful means of nitrogen removal of wastewater including night soil. A current concern about the process is the possibility that N₂O, a green-house effect gas could be released by the nitrogen removal. The mechanism of so called “aerobic denitrification” also remains to be elucidated. In this study, two lab-scale models of the nitrification denitrification process of a mixed liquor recycle type were operated under conditions similar to those of “High Rate Process” amply adopted in night soil treatment and characterized by high MLSS concentration and high volumetric loads of nitrogen and organic matter. During the operation, the content of nutritional metals (Cu, Fe, Zn, Mn, Co and Mo) in the influent was varied to investigate the effects of the metals on nitrification and denitrification. The deficiency of Mo in the influent resulted in a halt of the oxidation of NO₂^-to NO₃^-, which accompanied a prominent aerobic denitrification concomitantly releasing N₂O in a large amount. This finding suggests that Mo is a metal essential for preventing N₂O emission from the nitrification denitrification process.

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Aerated filters have the dual function of biological oxidation and filtration and are expected to replace rapid sand filters in tertiary treatment of sewage. Tertiary-treated sewage can have a high nitrogenous biochemical oxygen demand if there is inadequate nitrification, and it is important to keep nitrification levels in the treatment system high throughout the year. In an effort to develop an aerated filter with high nitrification capabilities, we formulated a new filter with two media. This filter has 2 layers. The upper layer is filled with a plastic medium and the lower with anthracite. We tested the filter with a pilot-scale apparatus on secondary-treated sewage. In the initial experiment, we filled the upper layer with a medium that had a small specific surface area (Type A, specific surface area about 500 m²/m³), and the medium was fixed with perforated plates. In second experiment, we filled the upper layer with a medium that had a large specific surface area (Type B, specific surface area about 800m²/m³), and the medium was fluidized by aeration. Higher nitrification performance was achieved in the second experiment the nitrification rate was 0.87 kgN/m³ per whole bed volume per day, at a water temperature of 20°C. A comparison between this second experiment and the initial experiment suggests that this improvement was due to an increase in the specific surface area of the medium.

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In order to evaluate Testacealobosia Arcella vulgaris as an indicator in nitrification process, the feeding habits on nitrifying bacteria and the effect of nitrogen compounds on the growth characteristics were examined comparing with those of Vorticella microstoma and Opercularia sp. In batch culture experiments, it was clear that A. vulgaris could grow well with Nitrosomonas europaea and Nitrobacter winogradskyi as food bacteria, whereas the growth of V. microstoma and Opercularia sp. was not observed. In addition, the inhibition effects of NH₄-N and NO₂-N on the growth of A. vulgaris were observed significantly. In continuous culture experiments, the strong relation between the concentration of A. vulgaris and nitrification ratio were found due to the close prey-predator relation with nitrifying bacteria and its high sensitivity to NH₄-N concentration. It is suggested that A. vulgaris is a good indicator for nitrifying process.

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The role of Dileptus anser on the detritus chain was studied in batch culture experiments carried out in three 500-ml Erlenmeyer flasks. Culture solutions of bacteria and Tetrahymena pyriformis were suspended in 500-ml Erlenmeyer flasks containing 100 ml of sterilized CE medium. 0, 1 and 8 cells ml^-1 of D. anser were added to each flask on day 0. Three series of experiments were performedusing the control system (No.1) and the systems with D. anser added (No.2, No.3). The batch experiments were carried out over a 7-day period at 20°C. Eight ml of the culture solution was collected from each flask on day 0, 3 and 7. The amount of bacteria was assessed by the plate culture method and direct method, and protozoan species were examined. The concentration of DOC and that of ATP containing one cell of bacteria were measured.
It was shown that the presence of D. anser led to a decrease in density of bacteria when therewas not enough T pyriformis as prey for D. anser. The clearance rate of DOC in each system on day 7 was 14, 26 and 49% respectively. The concentration of ATP contained in one cell of bacteria of each system on day 3 was 5.3×10^-13, 6.1×10^-13 and 8.2×10^-13mg-ATP·mg-cell^-1 respectively. It was found thata high concentration of ATP contained in one cell of bacteria led to a high rate of degradation of DOC. The study confirmed that D. anser greatly influences the population of other microorganisms, and the concentration of ATP contained in one cell of bacteria could enhance the degradation of dissolved organic carbon.

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Laboratory-scale experiments on a microfilter (MF) combined with high-concentration powdered activated carbon (PAC) was carried out using synthetic secondary effluent as a raw water. The MF membrane has a nominal pore size of 0.1μm and a surface area of 0.05m², and it was submerged into a 5-L reactor containing either 0g/L (control), 10g/L, or 40g/L of PAC. As a result of continuous filtration experiments, improvement of filtrate water quality and control ofmembrane fouling was demonstrated by the addition of PAC. However, when the organic substrates in the synthetic raw water were separated into three groups, i.e., 1) peptone and beef extract, 2) humic acid, tannic acid and sodium lauryl sulfate, and 3) arabic gum powder and lignin, it was found that the raw water containing arabic gum powder accelerated the membrane fouling process by creating a cake layer of PAC on the MF membrane. The primary cause of membrane fouling in the PAC-MF process was cake+gel layer formation (>98% of the total resistance), and the membrane pore blocking was very small (<2%), which was further reduced by PAC.

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For the efficient operation of the membrane bioreactors, the timing of the membrane cleaning should be determined not from experiences but from quantitative analysis of the past data thereby avoiding unnecessarily frequent cleaning processes. A physical model describing the fouling process of membrane was applied to Kalman filter algorithm and the prediction of the increase of the filtration resistance was carried out. Time-series discrete experimental data from a laboratory-scale experiment were used for the calculation. Predicted change of filtration resistance was in good agreement with the measured one when parameters in the model are correctly identified through the recurring calculation process. By a long-term prediction, frequency of membrane cleaning necessary for stable operation was predicted as well.

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To develop a garbage recycling system including garbage disposal, lactic acid and biodegradable plastics production, the preservation and deodorization of garbage during storage and the explication of their mechanisms are very important. The changes of counts of viable cell in garbage collected from university's dining hall during the storage were observed. In spite of seasons, lactic acid bacteria became preferential bacteria after the garbage was stored for 24 hours. On the contrary, coliforms and clostridia that are indexes of putrefaction and pollution remarkably decreased. The coliforms were not detected after the 72- or 96- hour storage. No food poisoning bacteria, such as staphylococcus aureus and bacillus cereus, were detected after the 24 hours storage. From the results of experiment adding the staphylococcus aureus to the garbage, it was proved that the lactic acid bacteria also easily became preferential bacteria even if food poisoning bacteria gained predominance at the beginning of the storage. It is clear from this study that lactic acid fermentation during the storage process inhibits the growth of putrefactive bacteria and food poisoning bacteria, which, as a result, makes it possible to realize the preservation and deodorization of garbage.

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Animal and vegetable industrial waste from food manufacturing are being estimated about 2.48 million ton annually, and after the volume reduction (dehydration, drying), the waste is reduced to 1.2 million ton annually. The recycling rate after volume reduction was about 80%. As for this, animal and vegetable industrial waste from food manufacturing generally show a high recycling rate. However, about 0.44 million ton of shochu waste stillage which is the vegetable industrial waste from the local food manufacturing is discharged annually (1997) in Kyushu, and the recycling rate is only 45%. From waste recycling point of view, the purpose of this paper is to show the procedure in making nutritionally well-balanced feed for domestic animals, using mixture of shochu waste stillage, rice straw and flour.
The authors conducted an experiment in making feed for domestic animals by squeezing the mixed sample (shochu waste stillage and rice straw mixture that was milled with a drug mill), producing a filtration residue which was left over in a filter with squeezing equipment, and adding flour to it.
The following results were obtained; 1) By adding rice straw to the shochu waste stillage and milling the mixture it is found that the range of particle size distribution became broad. It was also found that fibers from the rice straw act as a fiber membrane and that a lot of solids were contained in the filtration residue. 2) To produce the feed for domestic animals in this case, 86% of the water content is necessary for filtration residue. 3) The mixing rate of rice straw is 3%, and the milling time suitable for making the mixture sample (shochu waste stillage plus rice straw) is 3minutes. 4) Adding 3% of flour to the filtration residue made it easy to produce the feed.

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The effect of pH on the hydrogen production from the noodle manufacturing wastewater by anaerobic microflora was investigated using batch experiments with pH control at 35°C. Soluble carbohydrate was the main organic substance in the noodle manufacturing wastewater. The pH was changed from 4.0 to 8.5. The hydrogen yield was significantly influenced by pH. At pH of 5.2, the maximum hydrogen yield was 1.47 mol H₂/mol hexose (0.12gCOD H₂/g COD hexose) and 12% of COD was converted into hydrogen gas. At pH of 4.5, the hydrogen yield drastically decreased. At pH of 4.0, no hydrogen production was observed and lactate was predominantly produced, suggesting that hydrogenase was inhibited by the low pH. On the other hand, the hydrogen yield gradually decreased with increasing pH from 6.0 to 8.5. The concentrations of acetate and butyrate were changed by pH. In particular, the hydrogen production was accompanied with the butyrate production between pH 4.5 and 8.5. The results indicate that pH is a key factor affecting hydrogen gas recovery from the noodle manufacturing wastewater.

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Basic research was carried out to study sludge reduction by ozonation in an activated sludge process. This basic research was done towards the development of a wastewater biological treatment method with minimized excess sludge. Continuous tests were conducted, mainly to study the relationship between sludge liquefaction by ozonation and sludge reduction, as well as the stability of treatment in which activated sludge is deactivated in the liquefaction process. Studies were also made, through batch tests of activated sludge liquefaction by ozone injection, on the behavior of matter and changes in the degree of activated sludge nitrification activity. The liquefied sludge amount (ΔL) increased along an increase in the amount of injected ozone per day, as did the amount of sludge reduction (ΔX_R). The amount of sludge reduction versus the amount of sludge liquefaction (ΔX_R/ΔL) immediately after ozonation was 13, while that versus the same including the liquefied amount in the aeration tank was approximately 0.8. The S-BOD in treated water showed almost no increase, while the S-TOC, S-COD_Mn, and TP did. Comparing treatment by acidic ozonation, by which activated sludge was deactivated after the liquefaction process, and conventional ozonation, it was found that the quality of treated water worsened especially under high BOD sludge loads (0.2kg/kg/d), indicating that an effective sludge reduction was not being achieved. Batch test results showed that there was a progress in activated sludge liquefaction along an increase in the injected ozone. However, there was a drop in the relative sludge nitrification degree, a drop to 20% at an ozone injection rate exceeding 40 mg-O₃/g-MLVSS. A relation was also indicated between the elusion of K (Potasium) and the degree of activated sludge activity.

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Recently, the effluent standard of nitrogen and phosphorus was reexamined for the prevention of the eutrophication in Suwa Lake river-basin sewerage since 1995. The simultaneous phosphorus precipitation process has been introduced as a phosphorus elimination countermeasure. The phosphorus is surely removed by the flocculant, and it is finally removed as sludge and incinerated ash. However, phosphorus is rare resources. It is being estimated, when 10-15% phosphorus of phosphate rock imported as a fertilizer is included in the municipal wastewater. Therefore, it seems to be more important that it is recycled than disposing of the phosphorus in the sludge. With the basic experiment, it was confirmed that elution amount of aluminum of flocculant metal composition and phosphorus increased by treating the sludge of the simultaneous phosphorus precipitation process with alkali. It was confirmed that it could recover the phosphorus as hydroxylapatite, when calcium chloride is added to elution liquid, and can recycle elution aluminum as a flocculant. In addition, it was confirmed that it solubilized the sludge by the alkali treatment and can drastically reduce the sludge disposal cost.

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The toxic metal pollution is one of the major problems in environmental waters. Although the metal pollution has not been recently reported because of the development of successful removal technologies, the problem at relatively low concentration of metals still remains. The enhanced recovery of metals from water and wastewater becomes the social needs because metals have the toxicity to humans even at such low concentrations. Metals in wastewater adsorb easily to proteins in activated sludge and metals adsorbed are immediately dissociated with the increase of hydrogen ion concentration. These properties are available for both a metal recovery from environmental waters and a recycling after the metal recovery.
In this study, proteins that had the high affinity to copper (copper-binding proteins) were isolated from activated sludge culture using the affinity chromatography. As the result of the SDS-PAGE, the proteins were divided into two groups by their molecular weights. One group was from 43kDa to 30kDa and another was less than 30kDa. The latter group was the copper-binding proteins produced when copper ion was present as an inducer in the activated sludge culture.

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The reason of circulating treated wastewater (WW) in UASB reactors is the effective use of alkalinity. Generally, treated WW is circulated into the bottom of UASB reactor. Such method of circulation, however, does not ensure a stable condition in the reactor under higher loading rates. An improved method of circulation of treated WW in UASB reactor was investigated in this study. In this new method, called partial circulation method, WW was circulated into the middle of sludge bed. The experimental results confirmed that the method is not only capable of tolerating higher loading rates, but also can use the alkalinity more effectively. Experiments were conducted to investigate the shifting of the position of microorganisms in the reactor due to relocation of circulation. Methane producing bacteria was found to be shifted to upper parts of the sludge bed, while bottom parts of the bed was predominantly occupied by acid forming bacteria. Similarly, laboratory experiments were conducted to compare USAB reactors with complete circulation, partial circulation, and no circulation. In the partial circulation method, wash-out of SS was less and consequently effluent quality was better as compared to complete circulation. The investigation on the effect of reduction of buffer solution in substrate revealed that partial circulation method has a higher tolerance under low buffer conditio as compared to the complete circulation method.

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Water quality and aquatic insect were investigated over a year in the River Tamoki where river improvement works were conducted from 1991 to 98. Recovery of aquatic insect based on the diversity index by Shannon was late where supply of aquatic insect from the upper stream is resicted by a soil saving dam and the river bed was covered with foot protection blocks. On the other hand, it was fast where loose and settled stones with several centimeters and emerged plants are present. It was concluded that a soil saving dam and bed materials are important factors to recover water environment in rivers at which improvement works were carried out.

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Dispersal tendency of the adults of the water strider, Metrocoris histro, was clarified along a stream by the mark-recapture method, over a two-month's period Phenetic differences among members of 6 local populations from 6 streams within 3 rivers was estimated using the apterous males by multivariate morphometrics. Although the adult water striders generally seemed to be sedentary within a pool, the migrants showed a downstream bias in dispersal distance and in numbers of insects moving. Discrimination analysis showed that 67%-100% of the local group members were correctly classified into the original groups, and misclassification only occured among members sampled within a radius of 8-km. Thus the present result indicated that morphological similarity among members sampled from neighbor streams was higher than that among members sampled from the distant streams in a same river. Based on these results, patterns of dispersal and phenetic differentation of M. histro were discussed.

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Salt water from the sea flows up-and down-ward in tidal rivers due to tides. When mixing in a tidal river is relatively weak, a saltwater wedge is formed in it. The Kita river, the objective field in this study, located in eastern part of Kyushu island in Japan is in this state. When external forces are applied in an ecosystem, then changes might occur in response to any impact. The ecosystem in such a river is to be with more impact, because its aquatic zone in the tidal range is fragile and high in productivity. This study attempts to investigate the behavior of Deiratonotus japonicus, known as a scarce kind in the world, in association with salt wedge movement, to show relationships between water quality (ex. salinity, pH, turbidity, temperature, and dissolved oxygen) and hydraulic factors (ex. velocity and salt water intrusion) and to study the environmental condition on the habitat of Deiratonotus japonicus. Based on field observations, the habitat of Deiratonotus japonicus has a wide distribution correlated to salinity in the longitudinal direction in the tidal range.

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The scientific technique such as genetic engineering is important in both classification of the cyanobacteri a and analysis of the evolution process. The purpose of this research was to decide the base sequence of such cyanobacteria by 16S ribosomal RNA for the classification and its applications.
From the result of the experiments, the base sequences of musty odor and toxin producing cyanobacteria were determined, and cyanobacteria have many species specificity. Moreover, cyanobacteria were identified by PCR and FISH methods using proves with different species specificity. Musty odor producing cyanobacteria and toxic compound producing cyanobacteria were divided into two groups in phylogenetic tree. The former also could divide two groups, one was 2-methylisoborneol producing group and another was geosmin producing group. It is interesting when evolution is argued.
It was found out that the various forms of Phormidium tenue existed in Kamafusa Lake from the base sequences and its phylogenetic tree. For example, dark-brown P. tenue does not change from the indigo-blue P. tenue. Furthermore, occurrence of musty odor of summer and winter is caused by different P. tenue.

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A limiting substance on algal growth in Lake Koyamaike and influent rivers was studied. A chelating substance was found to be a limiting substance except during the summer period. The effect of the chelating substance on inhibition of algal growth by copper ions was examined. Detergents and domestic discharge were examined as the source of the chelating substance. The water bloom growth in Lake Koyamaike was shown to have a close relationship with treatment percentage in the discharge area. Both the treatment of domestic waste water and the usage percentage of paddy fields, which were demonstrated to be another source of chelating substance in the form of fertilizer outlet, affected water bloom growth.

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This research is the one that studied the effect and subject of the pre-reservoir based on the present condition of the Eutrophication of Miharu dam.
The following result was obtained about the effect of the pre-reservoir.
(1) The pre-reservoir is grasping 10% of T-N and 17% of T-P to the inflow load of when that is usual flow based on the surveys completed on Sep. to Dec.1998.
(2) It is grasping 28.4% of T-N, T-P to the inflow load at the time of the flood based on the surveys completed on Oct. 27-28, 1999.
Also, we understood the following as the load grasp characteristic of the pre-reservoir.
(5) The T-N and T-P load grasp quantity is correlated to flow fluctuation quantity
(6) It interlocks it to the fluctuation of SS load grasp quantity except the period in which flow decreases.

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In this study, we surveyed the species and the number of seedlings germinated from soils sampled from secondary stands of Quercus serrata in the Musashino terrace in the Tokyo Metropolitan area in order to grasp the relationships between the seed banks, actual stand floor vegetation and the land use around the stands. The following results were obtained. 1) The numbers of germinated seedlings were negatively correlated with the area of the stands. 2) The percentage of summer-annual and winter-annual plants, including man-dispersed species, were higher in soils sampled from the sites of smaller stands having a sparse shrub layer. 3) The percentage of plants dispersed by gravitation, which are characteristic in secondary stands of Quercus serrata, was higher in the larger stand sites having a dense shrub layer. 4) The results showed that the potential of seed banks is not as great as the reconstruction material for stand floor vegetation. This is because the percentage of common species germinated from sampled soil and those living in actual stand floor vegetation was low. 5) The soil at the smaller stands sites having a sparse shrub layer was tend to contain more weed species than characteristic species of the actual stand floor vegetation. Therefore if the soil taken from that site was used for the reconstruction material of the stand floor vegetation, the weed species would be dominated in the stand floor vegetation.

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We studied the growth of Sophora flavescens (Kurara) seedlings by the growth test for two years on the practical field at Nagano Pref., Japan to understand the methods for preservation and management for the grass field with Sophora flavescens growing. As results, many seedlings died under the dark condition that high grass species; Miscanthus sinensis (Susuki), Erigeron annuus (Hime-john) and Astilbe microphylla (Chidake-sashi) grow. It was considered that removing such as high glasses by the weeding to create the bright condition was effective to promote the growth and survival of Sophora flavescens seedlings.

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Zizania latifolia is profitable for nutrients uptake and the nutrient elimination of a enclosed system, serving as food for migrating swans. Experiments in the laboratory scale were conducted to inhibit the nitrification process and to estimate the nitrogen uptake as well as the nitrification in the rooting zone of the Zizania latifolia. In order to eliminate the effects of soil adsorption, experiments were carried out on water culture. Inhibition of the nitrification can be achieved by ATU and ATU did not influence Zizania latifoliain nutrient uptake for 7 days. It was found that the amount of removal of NH₄-H by the nitrification process was 4.7 times higher than that of the uptake in Zizania latifolia in September. It was also found that the reaction rate (K) by both uptake and nitrification was 0.146mg·L^-1·day^-1·g-Zizania latifolia^-1 and that by uptake alone was 0.0165mg·L^-1·day^-1·g-Zizania latifolia^-1.

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Adsorption behaviors for suspended particles such as kaolin, iron oxide (Fe₂O₃) and graphite were examined for a several kinds of protein (casein, gelatin, hemoglobin, albumin). Using iron salt coagulant and each protein, coagulation and foam separation experiments were carried out on kaolin suspension.
Casein and gelatin showed a high adsorptive activity on kaolin and Fe₂O₃. In contrast, the adsorptive activities of albumin on these particles were extremely low. Furthermore, the adsorbed amount of albumin on graphite as an index of the hydrophobicity evaluation was also little. As a result of suspension treatment by the coagulation and foam separation method, the turbidity removal rates of casein and gelatin were 98.6±0.3%(n=3) and 99.5±0.3%(n=3), respectively. In contrast, the removal rates of albumin and hemoglobin were less than 40%.
The high adsorptive activity of surface-active material on solids means that the potential of changing the hydrophilic interface of the solids to a hydrophobic interface is high. The hydrophobic solids are easily adsorbed on the bubble interface and are accumulated on the water surface. The characteristics of appropriate protein for the coagulation and foam separation method are the high adsorptive activity on solids and the high hydrophobicity. Casein has the high ability to make hydrophobic solids.

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In recent years, various on-site water purification systems have been introduced to cope with water pollution in urban areas. In spite of a large number of construction of the systems, engineering of the systems has not been developed and still been in immaturated stage since database of experiences from previous works has not been established. Establishment of the database was done and then publicized in a WWW, which will help an engineering planner avoiding from an arbitrary decision and client to make construction orders toward an ideal picture.The database system included databases of previous works, technical reports and research papers from academic journals and search systems for selecting appropriate. processes and providing how to manage the processes for users.

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In this study, the coagulation and foam separation for collection of red tide phytoplankton Peridinium bipes in fresh water was examined in a batch system. The coherency ofP.bipeswas worse than other phytoplankton. During the treatment of P.bipessuspension by the coagulation and foam separation without pretreatment, the cells were difficult to catch in the iron hydroxide floc, and the recovery rate was low. By pretreating with ozone or UV, however, the coagulation and foam separation method was remarkably improved, and the recovery rate was above 90%. The adequate coagulant dosages of ozone and UV pretreating methods were 3mg-Fe/l and 5mg-Fe/l, respectively. The casein dosage was 15mg/l in each case. The ozone method was faster than the UV method. The ozone method was accomplished in only 9 minutes. Iron and casein chemicals were scartely detected in the treated water of the ozone method. As a result of the AGP test, in a control medium and the treated water of the ozone method, the significant difference could not be observed. In conclusion, ozone aeration is the appropriate pretreatment for collectingP.bipesby the coagulation and foam separation.

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Ralstonia eutrophaKT-1 is a bacterium able to degrade trichloroethylene (TCE) by its phenol or toluene-degrading enzyme. Quantitative detection of strain KT-1 was examined with a real time PCR apparatus, in order to monitor the strain released into a field for TCE degradation. A 800 base-DNA fragment, PCR-synthesized by using a primer pair designed based on a repetitive extragenic palindromic (REP) sequence, was used as a target DNA for the detection. A primer pair with hybridization probes, designed from the sequence of the PCR-synthesized fragment, successfully detected strain KT-1 and detection limit was 20 cell-DNA/PCR-tube. This developed method was applied to the detection of strain KT-1 injected to ground water of a TCE contaminated site in Chiba prefecture. Strain KT-1 in the groundwater was monitored for approximately two months after the injection. The monitoring of strain KT-1 was successfully attained until the detection limit, showing the effectiveness of the quantitative PCR.

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Air sparging coupled with soil vapor extraction has been developed and applied to remove volatile contaminants from subsurface environment instead of groundwater extraction coupled with soil vapor extraction. The groundwater extraction requires water treatment like aeration on the ground. On the other hand, air sparging facilitates contaminant volatilization with air injected into groundwater and removes contaminant gas by soil vapor extraction in the unsaturated zone. Additionally, this technology accelerates aerobic biodegradation of contaminants like petroleum hydrocarbons by increasing dissolved oxygen concentrations in groundwater. This paper presented the results of the field test conducted to estimate the removal effect of volatile organic compounds with air injection into groundwater. The summary was as follows. Toluene and tetrachloroethylene concentration in groundwater smoothly decreased and were below the environmental quality standard within the zone of influence of injected air. Toluene concentration in groundwater decreased due to volatilization and aerobic biodegradation. And in the aerobic zone, biodegradation rate was larger than volatilization rate.

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A simple method to measure PAH and PAE in soil without time-counting operations, such as extraction, separation and concentration, or use of a large quantity of organic solvents was developed. Head Space Solid-Phase Microextraction (HS/SPME) method was adopted in the method. The appropriate condition to measure PAE and PAH was decided for the method, and the precision of the method was studied. Then, some samples of soil beside a heavy trafic road and near a plastic molding factory were investigated under the measurement condition decided in this study. The results showed that the density of PAH and PAE in soil decreased with distance from the road or the factory. This means that the HS/SPME method was effective for the measurement of semi-volatile organic matters in soil. With HS/SPME method, we can expect to get more information about the pollution of soil by semi-volatile organic matters like PAH and PAE, because we can execute operations more quickly and measure more samples with less contamination from measurement operations than with common extraction methods.

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A new simulation model was developed for predicting the fate of volatile organic compounds (VOCs) in activated sludge process. This model considers adsorption, surface and buble volatilization, and biodegradation from the dissolved phase as removal mechanisms. This model has the following characteristics compared with existing models: Oparameter values which can be determined from hydrodynamic conditions and controlled condition by operation, are calculated. 2) this model considers active heterotrophic bacteria that only degrade the target compound, and autotrophic nitrifying bacteria in acitive biomass. 3) mass balance about biochemical reactions, is considered. 4) data about biodegradation by specific active bacteria can be estimated by biodegradation tests and simulation tests validating the tests. The model was evaluated with experimental data using pilot plant. Target compounds were benzen, dichloromethane, toluene, and m, pxylene. As a result, the model fairly simulated the fate of the target compounds in activated sludge process. However, further improvements were considered.

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This study was conducted to evaluate the environmental safety of varius municipal solid wastes by acute toxicity test using Daphnia magna. Samples examined were fly ash from 3 municipal waste incinerator plants, treatment matters of fly ash, compressed plastic and residue of incombustible wastes. The bioassay was conducted by using a leachate of each waste. Toxicity of fly ash leachate to D. magna was very strong, and the toxicity level was dependent on the incineration type. The toxicity was influenced not only hazardous substances such as heavy metals but also by salts that were contained at high concentrations in the leachate. However factors affecting the toxicity level were much complicated it was impossible to specify the reason. Toxicity of fly ash was lowered by both cement solidification and melting, which are the typical treatment methods for fly ash. Compressed plastic and residue of incombustible wastes showed no acute toxicity to D. magna. But the leachate contained high concentrations of Cu, which might cause strong toxicity. Therefore, other constituents in the leachate had an effect of reducing the toxicity to D. magna.

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The objective of this study is to properly evaluate the potential health risks of residents near the antimony smelter. The critical pathways of antimony exposure to the residents around the smelter are considered to be a vegetable intake and inhalation from our previous study. In this study, antimony concentrations in ambient air at two sites near the smelter were measured for one week to improve the value of inhalation intake. Parameter values in the metabolic model of antimony were estimated more precisely. Health risks for the residents wereevaluated by comparing the calculated concentration of organs or tissues to the epidemiological data.
The results obtained in this study can be summarized as follows;
1) Antimony concentrations in ambient air around the smelter were varied day by day. It might depend on the meteorological condition or operation of the smelter.
2) Wet digestion- ICP-MS method was considered to be effective for the measurement of antimonyconcentration in suspended particulate of ambient air.
3) Antimony concentrations in lung of residents might excess the concentration in which man will onset a lung cancer.
4) Antimony concentrations in a human body of the resident were estimated two to ten times larger than the reference Japanese.

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Characteristics of estrogenic effect formed by chlorination of drinking water were investigated focusing on chlorination by-products. The MVLN assay was carried out to detect estrogenic effect. It was suggested that 17 β-estradiol would be a possible chemical that contributes to the estrogenic effect detected in the Lake Biwa water. It was speculated, however, that the effect of 17 β-estradiol is greatly suppressed by coexisting with organic matter in the Lake Biwa water. The main factor affecting the increase of estrogenic effect by chlorination would be the effect of chlorination by-products. The estrogenic effect of the Lake Biwa water was reduced by coagulation and granular activated carbon treatment. The estrogenic effect disappeared almost after activated carbon treatment. The reduction of the estrogenic effect by granular activated carbon treatment was consistent with the removal of TOC. In the meantime, the estrogenic effect of water after coagulation and activated carbon treatment increased by ch lorination. The important result is to find that there is a problem equal to the production of trihalomethanes even in the estrogenic effect of drinking water. The result shows that the estrogenic effect is formed as a result of the reaction of chlorine with organic matter remained after water treatment.

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The lab-scale experiments were performed to study suspended growth of heterotrophic bacteria and decay process of free and combined chlorine in reclaimed water. It was found that suspended growth of bacteria was suppressed by combined chlorine and that the rapid growth began after combined chlorine had been consumed completely. It was also found that the initial dose of the chlorine could delay their growth, but could not control the maximum count of bacteria. Decay process of free chlorine was described by the simple first-order reaction. To simulate disappearance of combined chlorine, two steps model of first-order reaction was required. The values of rate constants for the first-order reactions depended on the initial chlorine concentration. The simple model for simulating bacteria growth was developed with aid of the activated sludge model No.2 and data from experiments without chlorine dose. It was found that the simple model was also applicable to the experimental results with chlorine dose.

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The survival of the Cryptosporidium oocysts are affected in water temperature and storage time. We evaluated the survival of Cryptosporidium parvum oocyst under the conditions of controlled temperature from 4 to 60°C The survival ratio of oocysts was obtained using in vitro excystation-flow cytometry assay. As the result, the survival ratio of the oocysts rapidly decreased with the rise in water temperature. The required time for the decrease in the oocysts survival ratio of 90% at 60, 55, 50, 45, 40, 30 and 20°C was 3 min, 42 min, 3 hours, 31 hours, 7 days, 31 days and 150 days, respectively. The decrease of the survaival ratio of the oocysts at 10 and 4 °C was less than 10% after 150 days of storage.

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A new method was developed to detect viable Cryptosporidium parvum oocysts. For the excystation of viable C. parvum oocysts, Hank's Balanced Salt Solution with 1.5% taurocholic acid was used to excyst the oocysts, and nucleic acid binding membrane filters were used to recover chromosomal DNA from C. parvum sporozoites after DNA extraction with proteinase K. Polymerase chain reaction (PCR) method was applied to the final detection of the DNA extracted from excysted oocysts. For the PCR, a polythreonine gene region was targeted to amplify the C. parvum specific DNA. Amplified PCR product which was detected by agarose gel electrophoresis was confirmed by restriction enzyme digestion profiling and DNA sequencing. The method developed in this study is useful to detect viable C.parvum selectively. Therefore, this method is applicable to assessment of the actual infection risk of C. parvum and to evaluation of disinfection efficiency in the water supply systems.

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The aim of this study is to estimate water quality characteristics in up-stream area of Nagaragawa estuary barrage based on statistical analyses of “Nagaragawa Estuary Barrage Monitoring Data”. First, spectra of chlorophyll-a and DO data are evaluated by means of FFT (First Fourier Transform). Chlorophyll-a data have fluctuation component of about 10 day period affected by flood inflow in addition to fluctuation components of seasonal period and day period. Secondly, governing factors of chlorophyll-a and DO and their characteristics are investigated by means of Quantification Theory I. It is found that water temperature and growth of thermal stratification are the most important factors for the absolute value of chlorophyll-a and DO, though the governing factors seasonally change.

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Several studies have been made on the effect of the artificial reef construction on the algae and seaweed. But little is known about the transition of the algae on the surface of newly constructed reef This paper is intended as an investigation of the transition of the algae and seaweed on the artificial reef in the Hirota bay.
The results of this investigation showed that the transition of the ecosystem on the artificial reef could be showed by the index of diversity, and that the algae and seaweed on the artificial reef would be influenced by the wave and current around the artificial reef.

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Continuous samplings of atmospheric aerosols, gas and fallout were carried out from July 1998 to December 1999 at the peak of Mt. Birao in Teshikaga town, eastern Hokkaido, Japan. Also, we collected lake water both in Lake Masyu near Mt. Birao and Lake Kuttara in Shiraoi town, southern Hokkaido. Atmospheric concentrations of total particulate mass (TPM), carbonacious matter and sulfate were not shown seasonal variations, however, the concentrations of heavy metals such as lead, zinc and arsenic etc. significantly increased in winter. From the results of isentropic trajectory analyses, the pollutant was supposed to be transported from the direction of northeastern China and Siberia in winter season. Also the metals in insoluble atmospheric fallout significantly increased from winter to spring. Pollutant such as nickel and lead, which supposed to fall out from the atmosphere, in both lakes. Moreover, the concentrations such as zinc, nickel, vanadium and copper, tend to increase from those measured in 1981.

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Nitrogen and acid leaching from agricultural soil fertilized with compost was examined during acid rain fall conditions using soil columns. The pH value in the effluent from the soil columns increased to>8.0 although pH of rain water was 4.1. Exchangeable calcium and magnesium neutralized the hydrogen ions and eluted from the soil. Carbonate produced from the organic carbon in the compost was also useful for neutralization. Nitrification and denitrification occurred in the soil during low rainfall conditions, Sulfate reduction and sulfur denitrification also occurred in the soil. Supplement of exchangeable calcium by compost promoted to ion exchange in the upper layer. IC produced from the soil organic matters and the compost was also effective to neutralize the acid rain. In the lower soil layer, denitrification occurred and neutralized the acid rain. Fertilization with compost accelerated denitrification and sulfate reduction in the lower soil layer, and decreased nitrate concentration in the effluent.

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Dry deposition of particulate matter, organic carbon and PAHs (Polycyclic Aromatic Hydrocarbons) were measured at two stations in an urban area. While the deposition fluxes of particulate matter and POC were nearly constant, those of PAHs had seasonal variability. The inflow flux into a combined sewage treatment plant at this area was also measured during non-rainy and rainy periods, respectively. Diurnal changes in water discharge, particulate matter and PAHs were observed during each of the non-rainy periods, thereby suggesting diurnal cycle of human activity. The first flush phenomena that is faster runoff of particulate matter and PAHs than water discharge were clearly observed at all the rainy periods. Although their PAHs contents agreed fairly with those of dry deposition, their fluxes were a few times larger than those of dry deposition.

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The authors previously proposed a new model for manhole base shape with the invert located on the side wall of a manhole with right-angle pipes to reduce energy losses (1999). However, the alignment of connecting pipes in this model is different from the conventional position. For a new manhole model with a flat guide cover on the invert for a coventional manhole with right-angle pipes, the energy loss coefficient K (the total head loss/velocity head) is by about 0.6 to 1.3 smaller than the values of the conventional manhole type used in Japan. However, when rainfall in an urban area significantly exceeds the design value for rainfall on the storm sewer network, flood damage is unavoidable even if the energy losses at manholes in the area have been reduced. Recent changes in local rainfall patterns in Japan have caused frequent deluges that saturate the ground surface resulting in sever flood damage in low-lying areas. It might be possible to reduce flood damage in these areas by increasing energy losses at manholes upstream, and the intentional overflow from these manholes may delay the spread of flow over the ground surface downstream. When four kinds of baffle plate are installed in manhole outlets in straight pipes in order to reduce the cross-sectional area of flow to the downstream pipe, the energy loss coefficient K is by about 0.1 to 4.4 larger than the values of a conventional manhole type.

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In order to reduce leachate which is to reach to bottom of the landfill, diversion of rain at landfill surface must be indispensable. In this study, surface runoff over the cover soil and lateral flow within the cover were investigated to promote water removal from landfill surface. For the purpose, field measurement and laboratory experiment were conducted. From the result of field measurement and laboratory experiment, surface runoff were mainly dominated by hydraulic conductivity of cover soil. And lateral flow was generated at the condition that hydraulic conductivity of waste is lower than that of cover soil. However, even opposite condition of it, lateral flow derived by capillary barrier was generated at their boundary. Because of simulation results based on the theory of unsaturated flow and kinematic wave method were coincident with experimental results, runoff coefficients at steady state for various hydraulic conductivity were calculated and were summarized. Estimated runoff ratios gained from the simulation at varying slope length and rainfall pattern, designated that hydraulic conductivity lower than 10-5cm/s was necessary for effective surface water removal.

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Simouke Reservoir located at Ooita prefecture is equipped with fence as flow control device for countermeasure of freshwater red tide. In this study, the influence of fence on the flow and freshwater red tide in Shimouke Reservoir are studied. First, the accuracy of numerical analysis model for flow and water quality is evaluated by comparison with observed data. The results obtained by this analysis model are good agreement with observed flow data and water quality data. Secondly, the influence of fence on the flow characteristics and red tide (chlorophyll-a distribution) are studied under various fence establishment conditions. From the analysis result, it is found that though plankton increases in the case of existing fence, the influence of fence is to disperse planktons.

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Field observations have been made with respect to the diel vertical migration of dinoflagellate, Peridinium bipes and nutrient concentration profiles in a thermal stratified reservoir. Results showed that P. bipes could take nutrients and photosynthesize by migration in a calm thermal stratified mesotrophic reservoir. Faster migration from surface layer to middle layer was advantageous to take nutrients, and the possibility of active migration of P. bipes was suggested from the estimation of setting velocity. Furthermore, observational results suggested that P. bipes migration played an important role in nutrient cycling in a stratified reservoir.

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Nitrogen is considered as one of the limiting substrates of the primary production in Lake Kasumigaura. The concentrations of dissolved nitrogen (referred to as DTN) in Takahamairi area during wet weather periods were measured and the fate of DTN in the area under the storm conditions were analysed by a numerical model on the basis of measured data.
The conclusions are settled as described below;
1) 79 to 86 percent of DTN in the lake are attributable to the river inflows during wet weather periods, while the rest are supplied by scouring of lake sediment.
2) Unlike the movement of particulate nutrients, most of the DTN remain in the lake water over a period of 5days after the passage of a storm.
3) The rate of DTN transported from the inner water of the sediment by scouring (referred to as “exchange rate of di ssolution”) during wet weather periods was estimated from 30 to 95 times higher than the rate of diffusive DTN from the sediment during dry weather periods.

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Air pollutants which are emitted from municipal refuse incinerators, like chlorinated organic compounds, are generated corresponding to the state of combustion in the furnace. The combustion behavior of wastes is very complicated because the solid waste consists of various kinds of components and its reaction such as drying and combustion proceeds from the surface to the center of the solid, with time. In this paper, two types of experiments, each of which uses an electric furnace or an actual batch combustor, are conducted to analyze pyrolysis and combustion processes of the solid waste. CO, CO2 and hydrocarbon concentrations are continuously measured in each experiment. Hydrocarbons with low boiling point, which are major gas components generated at waste combustion and pyrolysis, were measured semi-continuously by a micro gas chromatograph, and concentration of total unburned hydrocarbons are measured as total organic carbons by a gas chromatograph. It was shown that the flow rate o the total organic carbon was similar to that of the CO. The similar and different of the gas generation processes in the electric furnace and the batch combustor were discussed.

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In this study, it is the purpose to determine the destruction efficiency of PCBs for various kinds of iron compounds. Fe, Fe₃C, α-Fe₂O₃, Fe₃O₄, α-FeOOH and so on, were used as iron compounds. 200μg of PCBs (a mixture of Kanechlor-400 and 600) was heated at 250-350°C with each iron compounds (0.1g) in a sealed glass ample. Fe₃C had the highest activity for decomposition of PCBs among the iron compounds under the experimental conditions. It was found that the combination of the carbon and iron contributed to the decomposition of PCBs.
Next, the destruction experiments of PCBs were performed using a tube type reactor to understand the effect of atmospheric condition on PCBs destruction. The decomposition ratio was high using both Fe₃C and the iron powder pretreated by H₂ gas under the N₂ and the N₂+O₂ atmosphere.

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