This paper shows how to evaluate the flow conditions in droughty and polluted streams in urban area, and also shows how to improve it. The environmental standard of flow (ESOF) is proposed here to give the target for improvement.
ESOF is decided with the scenic and ecological standpoints.
ESOF is compared with the flow without man-made effects (FWMMF), the equilized flow of whole rainfall in basin (EFWRB), the effluent from sewage treatment plants (ESTP), other effluents (EF), intaked water volume in the upstream (IWVU), and observed flow (OF), in order to evaluate the condition of flow and to adopt proper remedial measures.
This evaluating method is applied for 2 streams in Tokyo urban area, and flow of both streams are found to be much smaller than ESOF after the whole urban effluent is taken into sewer pipes.
(1) Flow augmentation from other basins or sewage treatment plants, or
(2) Change of stream's configuration into series of many ponds, is necessary in this case.

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A method for determining concentrations of 12 volatile organic pollutants which were added newly to the environmental standard for soil in Japan has been developed. By many conventional extraction methods for determining the pollutants, they could not be extracted completely from actual polluted soil samples.
In this study, it was found that concentrations of the pollutants in soil could be determined accurately and simply by the following procedures and conditions: (1) Put c.a. 5g of soil in a weighed centrifuge tube to which 10ml of ethanol has been added. (2) Weigh it to determine the accurate weight of the soil. (3) Shake vertically the centrifuge tube for 20min. (4) Leave the centrifuge tube for 48h to extract completely. (5) Shake hard for c.a. 20s after adding 20ml of pure water and 3-10ml of n-hexane for determination of MC, TCE, PCE and CCl₄, with ECD-GC or n-decane for simultaneous determination of all the pollutants. (6) After centrifuge, take 2-5ml of n-hexane layer or n-decane layer by glass syringe, and pass it through a cartridge filled up 0.3ml of silica for clean up. At this time, throw away from 0ml to 0.5ml of effluent and collect from 0.5ml to 4ml of it. (7) Analyze with ECD-GC or GC/MS.

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Scrubber-washed wastewater of Sludge drying process in sludge melting system contains both ammonium nitrogen and dissolved organic carbon (DOC) in high concentrations, and is also found to contain compounds which show inhibition to nitrification. In batch experiments, the inhibitory compounds are found to be biodegradable and also absorbable to activated carbon. Nitrification activity can be recovered immediately after the inhibition compounds are removed.
Therefore in this study, biological treatment process using a expanded-bed activated carbon reactor is applied to accomplish nitrification as well as removal of organic compounds from the wastewater. Under the condition where DO is more than 1mg·l^-1, TKN loading rate can be raised till 5mgN·(gGAC)^-1·d^-1 to attain more than 90% nitrification of influent nitrogen. DOC concentration in the bio-reactor should be maintained less than 40mgC·l^-1 for avoiding inhibition and assuring nitrification.

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The ecological role of sulface-reducing bacteria (SRB) in anaerobic degradation of a long-chain fatty acid (LFA) was investigated using three anaerobic sludge consorita cultivated at different sulfate loading rates. The three kinds of sludge (referred to as Sludge A, B and C) were cultivated in a fill-and-draw mode for 100 days by feeding with plamitate as a major carbon source (feeding concentration : 1.0g COD·l^-1), but with different levels of sulfate, i.e., 600mg-SO₄^2-·l^-1 for Sludge A, 300 for Sludge B, 0 for Sludge C.
Degradation of palmitate into acetate in the presence of sulfate can be performed by either of the following three trophic groups : 1) symbiosis between palmitate-degrading proton-reducing acetogens (P-PRA) and hydrogen-utilizing SRB (H-SRB), 2) symbiosis between P-PRA and hydrogen-utilizing methanogens (H-MPB), 3) palmitate-oxidizing SRB (P-SRB). Three sludge consortia exhibited different behavior of palmitate degradation, depending on their sulfate loadings. As for Sludge A, the first group, P-PRA+H-SRB had the greatest contribution in palmitate degradation, and the extent of the second, P-PRA+H-MPB and the third, P-SRB were about half of the first, respectively. For Sludge B, P-PRA+H-MPB had the superior contribution over P-PRA+H-SRB and P-SRB. The lowest contributor, P-SRB was only one-tenth of the largest contributor, P-PRA+H-MPB. For Sludge C, palmitate degradation was accounted for only by P-PRA+H-MPB, and the contributions by P-PRA+H-MPB and P-SRB were negligible small.

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The method of rapid infiltration through soil lacks the ability in removing nitrogen from wastewater reason of insufficient of organic substances for denitrification in the anaerobic region. To urge the denitrification it was tried by pouring organic compounds into the deep region of the infiltrator, where the process of nitrification completed and the soils get to be anaerobic. For understanding the processes occurred in this procedure, the mathematical models (with the Finite Element Method) are presented to simulate the flowing and mixing processes occurred within the two-dimensional designed experimental apparatus. Because the hydraulic conductivity of water in variably saturated soils depends on pressure head and water content, this problem is strongly nonlinear. To solve this problem, the Newton-Rampson method have been utilized and the calculated results agree well with that of experimental ones. From the calculated results, a low ratio of denitrification is presumable according to the low mixing between these organic matters and nitrate by means of supplying organic substancs from single point.

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