Coliphage concentration and fecal coliform concentration in a river, estuary and sea in series were measured for seven times in a year. Three kinds of host cells, namely E. coli K12 F⁺ (A/λ), E. coli B and E. coli C and application of RNase enabled to detect four groups of coliphages. Coliphage concentration ranged from 40PFU/mL to 410PFU/mL in the river, from 0PFU/mL to 45PFU/mL in the sea in using E. coli K12 F⁺ (A/λ) strain. Coliphage counts obtained by other two strains were almost same as or slightly less than that obtained by E. coli K12 F⁺ (A/λ). Correlation between coliphages and fecal coliform was low. Excluding the effect of the dilution of the river water by sea water using the value of electric conductivity, coliphages transported along the river could be assumed to be constant in number, while fecal coliform was sometimes decreased or increased. Viruses, like coliphages, are possibly transported along a river, being decreased in concentration only with the dilution by sea water.

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Effects of carbon dioxide injection before the chlorination on inactivation efficiencies of E. coli B, S. faecalis and coliphages in the secondary effluent were investigated.
The carbon dioxide injection into the secondary effluent could decrease the pH value of the secondary effluent from 6.1 to 4.8.
The carbon dioxide injection brought about more effective inactivation for E. coli B when the chlorine doses were 1.5mgCl/l and 3.7mgCl/l, respectively.
However, the carbon dioxide injection before the chlorination did not make better efficiency for the inactivation of S. faecalis.
The coliphages were also inactivated more effectively by the carbon dioxide injection before the chlorination when the chlorine doses were 5.0mgCl/l and 12.0mgCl/l, respectively.

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Infiltration strata is an artificially devised soil structure used to reduce urban stormwater discharge. The major functions of this strata are 1) the passage of stormwater at the surface, 2) the retention of this water within the strata and 3) the exfiltration of this water into the natural base soil. We have developed a model to predict the behavior of stormwater within the strata, based on the numerical solution of Richards' Equation with appropriate soil property functions. This model was verified using the drainage data of column experiment. The predicted drainage volume was similar to that of observed one, but rapid changes in the drainage rate produced by changes in the rainfall rate were not adequately predicted. Hysteresis effect which makes the soil property functions irreversible and many-valued was introduced using the Mualem's model, and the rapid changes in the drainage rate could be well predicted. Using this model, the performance of the strata was simulated. Clearly the performance depended on the exfiltration rate into the natural base soil. The drainage infiltration strata, which has a drainage pipe at the bottom of the strata, could be effective when the rate of exfiltration into the natural soil is small.

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Water quality of River Ogawa of Sapporo, located in the northern island of Japan, was analyzed from the data taken every day (every week in winter) frow September, 1986 till August, 1988. R. Ogawa (catchment area: 11km², length: 7.0km, average flow<at sampling point>: about 0.8m³) is flowing down the forest mountain, Mt. Muine (1461m). In this report, we focused the specific behaviors of nutrients during the snow melting period. Results are;
(1) The rate of water load during this season was about 60% of yearly discharge. The rate of nutrients loads was surpassed 60%.
(2) Most of nutrients of this period were scrubbed out from soil and some of them were eluted out from accumulated matters.
(3) Nitrogen flew out mainly in dissolved form (almost as nitrate) and phosphorus in particulate one.
(4) The mean water quality of this period was in meso-eutrophic condition.
(5) Run-off pattern of chemical components during this period which were arranged by L=C*Q=c*Qⁿ (L: chemical component load, C: concentration, Q: flow, c, n: constant) showed nearly the same tendency as one through the whole year. Concentrations of nutrients, except ammonium, became dense as the flow increased (n>1). Concentration of ammonium and ordinary inorganic components was stable or somewhat decreased.(n=1or<1)

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For a rational design and operation of a biofilm reactor for the treatment of water and wastewater it is necessary to clarify the mechanism of biofilm formationand detachment and to estimate the biomass hold-up retained within the reactor. In this study the biofilm development was recorded on video tape and the relationships between the biofilm detachment rate, the content of extracellular biopolymer (ECP) and the area of cavity, which was formed at biofilm/substratum interface, was quantified to investigate the type of biofilm detachment and what factors govern the phenomenon. Experimental biofilm which consisted of denitrifying microorganisms was established on the surface of the polyvinyl chloride plate. Three types of large biofilm detachment were observed. The first type showed that about 30% of the biofilm detached cleanly from the surface of the substratum after about 40 days. It was considered that this type was caused by the formation of the cavity and the decrease of the ECP content. The second type was revealed that a part of the biofilm detached from the middle of the biofilm in the course of 60-90 days. This phenomenon seemed to be attributable to the gas production within the biofilm. The third type displayed a combination of the first and second types after about 100 days.

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The characteristics of the cross-flow filtration of polymer suspensions, municipal wastewater and activated sludge were investigated using microfiltration membranes and ultrafiltration membranes. The flux decline was explained by a gel-layer model in which scouring effect at membrane surface was considered. Physical meanings of the parameters in this model were examined by experiments on various conditions. The observed specific filtration resistance implied that the gel-layer consisted of smaller particles than those in the bulk of municipal wastewater and mixed liquor of activated sludge. By adding polymer particles to the activated sludge steadystate flux was not increased but the rate of flux decline was decreased. These phenomena were explained by changes in the structure of the gel-layer.

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An oxygen supply method to wastewater using gas permeable film in the form of tube was investigated for the purpose of reducing energy consumption for supplying oxygen. Oxygen transfer rate was measured in the case with or without biofilm, which proved the high rate of oxygen transfer with nitrifying biofilm supplied with ammonium substrate. Simultaneous nitrification and denitrification occurred, when the tube with nitrifying biofilm was applied to the treatment of wastewater, resulting in the high rate of organic matter removal. However, periodic sloughing of denitrifying biofilm which formed on the nitrifying biofilm was needed to keep the oxygen transfer rate high. Energy comsumptiom of the process using this tube was calculated to be less than 40% of that of the activated sluge process.

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Batch-cultivation experiments were carried out in order to investigate the utilization of various fatty acids and hydrocarbons for Nocardia amarae from foaming activated sludge. The optimum ultrasonic wave time was determined to be 2 minutes for the measurement of vial cell count and OD₆₀₀. It was shown that both low-class fatty acids (C2-C5) and pharaffinic hydrocarbons (C12-C20) were utilized by N. amarae, and that the highest specific growth rate was obtained in case of octadecane (C18), which was 5.20 (1/day). It was observed that the different flocs of N. amarae were formated in accordance with the medium compositions, in particular that the floc in case of hexadecane was the disk type and about 5mm in diameter, which was formated at the hexadecane-solution interface. As the above-mentioned results, the capability of applying the octadecane and/or hexadecane medium to the colony counting method was suggested.

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Phenol removal capability of channel flow process was studied. It was shown experimentally that channel flow process could remove phenol perfectly under volqmetric phenol loading rate below 17mg/l·day. The reaeration coefficients at joint part of water channel were determined experimentally. By taking the oxygen balance, which incorporates surface reaeration, reaeration at joint part and influent DO concentration, the oxygen supplyed by algae (biogenic oxygen) was revealed to play an important role in phenol removal. The amount of attached sludge on string type contactor decreased under conditions in which phenol remained in water channel, but the amount of attached sludge on channel wall increase steadily during experiments. Observed sludge yield (Y_ob) was determined to be 0.270g-MLSS/g-TOC based on the estimated amounts of attached sludge at the end of experiments. The specific microorganisms for phenolic wastewater treatment by channel flow process were Beggiatoa and Oscillatoria. The accumulation of agar-like substances was recognized in first water channel in which Beggiatoa dominated. The protozoa diversity in water channel was decreased with increase of volumetric phenol loading rate.

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In anaerobic waste treatment processes, the acetogenesis stage requires proper control of hydrogen by reducing the concentration of it in the formation of methane and hydrogen sulfide etc. Propionic acid is the most key low molecular acid in the acetogenesis process in terms of hydrogen control. We found that when propionic acid decomposition took place with sulfate reduction, the acetogenesis completed at a much faster rate than that of without sulfate reduction. Results of the experiments indicated the possibility of symbiotic activities between aceto- and hydro-genic bacteria and sulfate reducing bacteria in terms of hydrogen transfer. A mathematical model based upon modified Monod type kinetics was introduced to describe the propionic acid decomposition with and without sulfate reduction. The model could well simulate the experimental results.

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Ammonia-selective zeolite “clinoptilolite” was used to remove ammonia-nitrogen from synthetic river water which also contains Na⁺, K⁺, Ca²⁺ and Mg²⁺ ions. Ammonia-nitrogen between 1.5[mg/l] and 3.5[mg/l] was completely removed from the synthetic water though the above competing cations were present. During service period of an ion-exchange column, 1500-1700 Bed-Volume of water containing 1.5[mg/l] NH₄⁺-N was applied before experiencing a break-through. The applicable water volume was reduced to 900-1100 BV, however, when the influent NH₄⁺-N concentration was raised to 3.5[mg/l]. Two models, i. e. the equilibrium model and the non-equilibrium meodel, based on the independent characteristics of selectivity coefficients of an arbitrary pair of cations, were presented to predict effluent cation concentrations. Both models showed good agreement with experimental results, whereas, within the range of this experiment, the equilibrium model seemed to be superior because of its simplicity. Once an ion-exchange column had experienced a break-though, regenerating solution containing 0.3N NaCl was passed through the zeolite bed and, then, introduced to the nitrification-denitrification reactors. After a short period of bacterial acclimation to salinity, more than 95% of NH₄⁺-N in the waste regenerant was removed biologically, giving evidence to the effectiveness of the proposed process.

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Effects of local urbanization on the regional-scale climate and air quality have been examined by analyzing historical data of meteorology and air quality in 1975 and 1985 in Nobi Plain, which is located on the Pacific Ocean side of central Japan. During the decade, about 12%(-400km²) of total land area in the region was changed from rice paddy field or forest to urban or bare soil area, resulting in an increase in ratio of urban (plus bare soil) area from 40.4% in 1975 to 53.1% in 1985. The analysis was performed for total eighteen days under high pressure system from May through September in both years. The results show that:(1) Daily-high-temperature zone shifted from intense urban-complex in coastal area in 1975 to inland in 1985, while temperatures in the urban-complex did not change significantly in these years. The shift can be attributed to horizontal transport of the heat accumulated in sea breeze layer, which heated up over newly urbanized surfaces in the sea breeze's fetch by artificial sources and increased-sensible-heat-flux.(2) Shift of the zone of high NO₂ concentration also well-correlated with that of the high temperature. These results suggest that urbanization in coastal area affects climate and air quality in inland area (i. e., regional effect of local urbanization), and thus necessity of the planning of land-use to preserve atmospheric environment in regional scale.

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Sewage sludge generated in Japan amounted to approximately 1.3 million tons per year as solids in 1986, and some 60% of the total amount was incinerated. Currently, most incinerated ash has been disposed by landfill and coastal reclamation, but effective utilization of incinerated ash is urgently required due to a reduction in disposal sites and for reuse of resources. This investigation intended to establish techniques to judge the soil conditioning effect of incinerated ash of sewage sludge when used as a soil conditioning additive for excavated soil and others. It also studied the hydration characteristic of incinerated ash and the strength of the conditioned soil. The results show that the soil conditioning effect of incinerated ash of sewage sludge depends on the degree of the hydratior reactivity. In addition, a hydration rate test is proposed as a simple method to judge the soil conditioning effect.

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Risk assessment and benefit estimation of TBT compounds used as anti-fouling paint to prevent hull and culturing net being protective from propagation of sessile organisms was performed in perspevtive of regional basin, Osaka Bay in Japan. It was based on environmental fate simulated by using Basin-wide ecological model which was validated by comparing of regional observed data. Predicted concentrations in each compartment were respectively 1.9-466.8ppt in water, 3.0-155.0ppb in sediment and 0.02-0.93ppm in fish, which were almost same order of regional observed data. Risk of TBT was evaluated very high on aquatic life in some places which was estimated by dividing predicted concentration in Benthos (very sensitive species) with MATC. While it was low on human being to extent negligible which was evaluated by dividing predicted intake with ADI. Benefit of TBT was estimated as relative benefit to copper paint by using the indicators of energy saving and dry docking period of ship.

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A set of nutrients (T-N and T-P) removal equations for anaerobic-anoxic-oxic process has been proposed for municipal wastewater treatment plant designs. The equations were composed with some parameters, such as biomass concentration (X), BOD volumetric loading (L_L), nitrifier recycling rates (R) and hydraulic detention time (T). The proposed equations were evaluated by data acquired at some laboratory and full scall plant tests.
Laboratory tests using 6 set of 30-litre sequencing batch reactor with nitrifier storage tank each have been carried out dosing artificial wastewater. Three cases of substrate loads supplied and four cases of R have been applied at the tests.
The data of full scale plant tests were acquired in Arakawa basin-wide (Saitama) and Toba (Kyoto) wastewater treatement plants. T-N and T-P concentrations in wastewater was ranges 10 to 25mg·1^-1 and ranges 1 to 5mg·1^-1 respectively. R applied were from 1.1 to 1.3.
The calculated T-N and T-P were fairly comformed to the data acquired by laboratory tests, except R=1 and 1.4 data which were varied widely. Calculated T-N and T-P were lower than 15 to 25% and 10 to 20% respectively, compared to the full scale-plant data.

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Bacterial population in mixed culture is evaluated from the property of removal activity of selected substrates in considering of the substrate interaction. When the substrate interaction does not occur in removal of the mixture of two substrates, i. e., the TOC removal rate of the mixture is shown by the summation of the TOC removal rate of each substrate, it is recognized that there are two kinds of bacteria which uptake different substrates, respectively. When this interaction occurs, i. e., the TOC removal rate of the mixture is shown by the TOC removal rate of one of substrates, it is recognized that identical bacteria uptake one of two different substrates each other. The concept of the substrate interaction is also valid from the respiration rate of mixed culture. The activated sludge acclimated with acetate is composed of three kinds of bacteria which uptake acetate, glucose and medium-chain saturated fatty acids, respectively, however medium-chain fatty acids such as butyrate, valerate and caproate, are uptaken by identical bacteria.

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The reuse system of city domestic wastewater are now coming to be rather popular in Tokyo metropolitan area. In the water quality aspects of reuse of treated wastewater, the remained odor problem is one of the most urgent ones to be solved. The purpose of the present study is to initiate the first step to identify the odorous substances themselves, to find the main source of production of the odorous substances, and to investigate the efficient methods of removal of the odorous substances.
It has been reported that the principal odorous substances from sewage treatment plant are sulfur compounds. Gas chromatography with flame photometric detector (FPD), which is sensitive to sulfur compounds, was used for the chemical analyses of the odorous substances, Analyses of head-space gas showed that sulfur compounds were sharply removed through an aeration tank and sludge treatment processes were related to production of odorous substances. Using a purge & trap concentration method, sulfur compounds such as methyl mercaptan, dimethyl sulfide, and dimethyl disulfide are isolated and identified from the final effluent of the conventional activated sludge process. For the removal of the odorous substances, the aerated filtration of the activated carbon bed was found to be effective.

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We studied on the optimum condition for micro-organism to produce biodegradable plastic (PHB) in activated sludge. The first experiment was made to confirm the production of PHB under nitrogen limited condition. Carbon content of dried activated sludge had risen rapidly after nitrogen in medium was completely consumed, white precipitate was extracted from dried activated sludge with hot chloroform and n-hexane after another 48 hours. We identified it was PHB by use of X-ray diffraction, DTA and CHNS-elemental analyzer. The second experiment was made to investigate the effect of carbon sources and cultivation period on PHB content under nitrogen limited condition. Consequently, CH₃COONa was better than glucose as carbon source for production of PHB. Content of PHB was stabilized to its maximum stage around 250 hours by continuous process and it was achieved to 12% of dried sludge weight basis. The third experiment was performed to grasp the difference of production rate of PHB and carbohydrate. PHB was slowly accumulated than carbohydrate. Consumption of PHB, observed with decrease of TOC in medium was also slow.

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Photographic processing wastewater bears high level of COD which is partially biodegradable. The process comprising three steps has been proposed. The wastewater is treated biologically in the first step, and the remaining nondegradable components are converted into biodegradable compounds by ozone in the second step and are treated again biologically in the final step. In this study, the activated sludge process combined with membrane separation has been applied to this first biological step and its effluent was ozonated.
MLSS was about 10, 000mg/l for 5 days of the hydraulic retention time (RT) for the wastewater from color developing process, and the overload, RT less than 5 days, caused great depression of sludge activity. MLSS was about 60, 000mg/l for one day of RT for the mixture of wastewater from various photographic processes. Five or more days of RT was necessary to obtain 90% or more COD removal for the wastewater from color developing process, and 10 or more days of RT was for the mixture. BOO of effluent from the first biological step increased in the beginning of ozonation and reached a maximum level, and then decreased gradually. Results of liquid chromatography and UV spectrophotometry suggested that ozone broke down the benzene ring of nondegradable aromatic compounds and converted them into biodegradable compounds. On-off control of ultra-filtration membrane unit was successful in long-term stable operation without cleaning because the clogging was prevented by waterhammer and bachwashing when the circulation pump was switched on and off.

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