2002 Fiscal Year Final Research Report Summary
A development research of activated sludge process without excess sludge using electrolytic process
| Project/Area Number |
13680664
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
環境保全
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| Research Institution | Ube National Colledge of Technology |
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Principal Investigator |
MURAKAMI Sadaaki Ube National College of Technology, Department of Biological and Chemical Engineering, Professor, 物質工学科, 教授 (00035065)
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| Co-Investigator(Kenkyū-buntansha) |
FUKAGAWA Masayuki Ube National College of Technology, Department of Biological and Chemical Engineering, Professor, 物質工学科, 教授 (20043870)
SHINAGAWA Emiko Ube National College of Technology, Department of Biological and Chemical Engineering, Professor, 物質工学科, 教授 (20116726)
TAKEUCHI Masami Ube National College of Technology, Department of Biological and Chemical Engineering, Professor, 物質工学科, 助教授 (30043889)
IMAI Tsuyoshi Yamaguchi University, Faculty of Engineering, Department of Civil Engineering, Associate Professor, 工学部, 助教授 (20263791)
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| Project Period (FY) |
2001 – 2002
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| Keywords | activated sludge process / excess sludge reduction / excess sludge substrate / electrolysis chlorine / cell killing / organic wastewater / biological wastewater treatment |
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| Research Abstract |
(1)Purpose
The purpose of this study is the establishment of the processing technology to recover nickel and phosphorus, organic substance and ammonia for the wastewater, and the guideline of design and operation of the processing plant necessary for the commercialization of this technology.
The sludge, which arises from treatment plants of domestic and industrial wastewaters, occupies the maximum proportion in the industrial wastes, and the enormous costs are spent for its treatment and disposal. In this study, the activated sludge process without excess sludge was developed using electrolytic process that converts the excess sludge into the substrate and is returned to the aerator.
(2)Principle.
The microorganisms (excess sludge) are killed by chlorine (hypochlorous acid) created electrochemically, and it is returned to the aeration tank. The killed microorganisms are extinguished by the other microorganisms through the bacteriolysis with the immediate digestion of the easily decomposabi
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lity materials and the long time digestion of refracoty substances such as the cell wall components.
(3)Results
The sludge was added with NaCl to be 1% and converted to the substrate by the electrolysis process for 10 minutes at 3.0V and 1.0A under agitation with anode plate of IrO_2 coat titanium and cathode plate of titanium.
The killed rate of the microorganism by the electrolysis was almost 100%. The process operation was optimized for NaCl dosage and electrolysis condition. About 20% increase by the return of sludge substrate was estimated for the load of the aeration tank with SRT of 20 days. MLSS was increased up to 16% of that in the control. The cell wall components were digested for several day. Several months were needed for the domestication of bacteria concerning the digestion of the sludge substrate. When the process water quality was compared with the control, BOD was same level, and COD and TOC increased a little. The treatment system without the excess sludge was established, and the workability and stability of the system were confirmed through continuous operation for one year.
(4)Prospect
In the future research, the demonstration experiment is necessary to be carried out in the public sewage treatment facility by cooperating with the private enterprises to commercialize this technology after the technology recognition. Less
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