| Project/Area Number |
05558073
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| Research Category |
Grant-in-Aid for Developmental Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
環境保全
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| Research Institution | THE UNIVERSITY OF TOKYO |
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Principal Investigator |
YAMAMOTO Kazuo Univ.of Tokyo, The Graduate School of Engineering, Associate Prof., 工学系研究科, 助教授 (60143393)
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| Co-Investigator(Kenkyū-buntansha) |
FUTAMURA Osamu Ebara Co.Ltd., Ebara Research Institute, Team Leader, チームリーダー
NAGAOKA Hiroshi Musashi Insitute of Tech., Faculty of Engineering, Lecturer, 工学部, 講師 (90207986)
OHGAKI Sinichiro Univ.of Tokyo, The Graduate School of Engineering, Professor, 工学系研究科, 教授 (20005549)
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| Project Period (FY) |
1993 – 1994
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| Project Status |
Completed (Fiscal Year 1994)
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| Budget Amount *help |
¥7,800,000 (Direct Cost: ¥7,800,000)
Fiscal Year 1994: ¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 1993: ¥5,000,000 (Direct Cost: ¥5,000,000)
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| Keywords | small-scale treatment / advanced treatment / membrane separation / phosphorus removal / membrane separation activated sludge process / MSB / column treatment / hollow fiber membrane / 高度処理 / 小規模排水処理 / 水循環 / 窒素除去 / 吸着 / エネルギー評価 |
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| Research Abstract |
This research has been done to develop an advanced wastewater treatment system for household water-reuse. Main results are summarized as below.
(1) Membrane Separation Treatment : Applying a single-stage intermittent-aeration process for nitrogen removal, it is recommended to operate the process with a cycle of 90 min-aeration and 90 min-nonaeration, at volumetric nitrogen loadings of less than 0.06 kgN/(m^3d). Then, we could achieve high nitrogen removal even at very low temperature as low as 5ﾟC.Hollow fiber or flat sheet membrane modules are suitable to immersed-type membrane separation activated sludge processes. It is recommended to make membranes flexible and give aeration beneath the membrane modules. Thus, air scrubbing is the best way to prevent flux decline. Intermittent suction gives a stable flux : even the intermittent cycle as long as 12 hours is allowable. We can adjust the intermittent cycle corresponding to flow-fluctuation. In order to get a stable operation of hollow
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fiber modules, it is recommended to keep tansmembrane pressure less than 30 kPa and the ratio of air babble upflow velocity to flux greater than 1800.
(2) Phosphorus Removal Column : Dewatered sludge granules from a water purification plant were very effective for phosphorus removal from the effluent of membrane separation activated sludge process. Almost 100% removal was achieved by them in two-stage in-series columns of each 3.5-hour detention.
(3) Photoreactivation of fecal coliform following ultraviolet disinfection was at most about 50%. Thus, it is recommended to use ultraviolet disinfection just before use-point. If a higher removal in terms of color and refractory organic carbons is required, a biological activated carbon-microfiltration process is available. 80% of TOC from refractory organic matters was removed at a dose of 20g/l of powdered activated carbon.
(4) Life cycle energy was estimated for various water recycle systems in urban area including membrane separation treatment. It was revealed that a household membrane separation treatment/reuse system was energy-saving comparing to existing water supply and sewerage systems, when density of household was less than 90 houses/km^2. Less
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