2000 Fiscal Year Final Research Report Summary
ELUCIDATION OF REMOVAL MECHANISM OF ARSENIC FROM SEWAGE SLUDGE AND INCINERATED ASH OF SEWAGE SLUDGE AND DEVELOPMENT OF ITS REMOVAL METHOD
| Project/Area Number |
11650555
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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 |
Civil and environmental engineering
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| Research Institution | IWATE UNIVERSITY |
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Principal Investigator |
UMITA Teruyuki IWATE UNIVERSITY, FACULTY OF ENGINEERING, PROFESSOR, 工学部, 教授 (30117072)
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| Co-Investigator(Kenkyū-buntansha) |
ITO Ayumi IWATE UNIVERSITY, FACULTY OF ENGINEERING, RESEARCH ASSOCIATE, 工学部, 助手 (90312511)
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| Project Period (FY) |
1999 – 2000
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| Keywords | ARSENIC / SEWAGE SLUDGE / INCINERATED ASH OF SEWAGE SLUDGE / SULFUR OXIDIZING BACTERIA |
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| Research Abstract |
Alkaline condition eluted arsenic in the sewage sludge more than acidic one. Alkalization of sewage sludge to pH 9 and 11 eluted arsenic more than 80 and 95%, respectively. It was found that the predominant form of arsenic eluted from the sludge was arsenic acid at pH5, 7, 9 and 11 by using a HPLC-MS, whereas it was arsenious acid at pH1. The eluted amount of of monomethylarsonic and dimethylarsinic acids was small compared with those of arsenic and arsenious acids. This result indicated that the form of arsenic eluted depended on the pH-EH diagram of arsenic in an aqueous system. It was shown that the addition of iron oxidizing bacteria and ferric iron was effective for the elution of arsenic on the acidic condition since arsenic sulfide in the sludge was oxidized by them and it caused the elution of arsenic.
The possibility of continuous arsenic elution from incinerated ash of sewage sludge was studied. The pH of ash dropped below 1 by adding waste containing sulfur produced from desulfurization process of digested gas and sulfur oxidizing bacteria surviving in the digested sewage sludge. It was found that more than 80% of arsenic in incinerated ash could be eluted continuously on the condition of a solid retention time of 10 days, solid concentration of ash of 20 gD.S/L and waste concentration of 20gW.T./L.
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Research Products
(10 results)
