| Project/Area Number |
14550553
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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 | Kisarazu National College of Technology |
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Principal Investigator |
UEMURA Shigeki Kisarazu National College of Technology, Civil and Environmental Engineering, Associate Professor, 環境都市工学科, 助教授 (60300539)
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| Co-Investigator(Kenkyū-buntansha) |
OHASHI Akiyoshi Nagaoka University of Technology, Environmental Systems Engineering, Associate Professor, 環境システム工学系, 助教授 (70169035)
HOAKI Toshihiro Taisei Corporation, Technical Research Center, Senior Research Engineer, 生物工学研究室, 課長(研究職)
TAKAHASHI Katsuo Kisarazu National College of Technology, Civil and Environmental Engineering, Professor, 環境都市工学科, 教授 (20005490)
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| Project Period (FY) |
2002 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 2003: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2002: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Keywords | livestock waste / methane fermentation / indicator microorganisms / total coliform / fecal coliform / fecal streptcocci / coliphage |
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| Research Abstract |
Digested sludge from a biogas plant treating livestock waste should be recycled to agricultural land as a liquid fertilizer. To fully guarantee the safety of the digested sludge, it is necessary to focus our attention on how the pathogen indicator microorganisms are removed/inactivated in the biogas plant. In this study, inactivation of indicator microorganisms through methane fermentation process was investigated in a full-scale biogas plant treating livestock waste. The plant was built to establish a circulative system to use livestock waste and local organic resources from the livestock breeders in the large-scale dairy farming area in eastern Hokkaido. The by-products, such as biogas and liquid fertilizers, are co-used by the livestock breeders.
Indicator microorganisms used in this study were as follows :
Total coliphages : indicator of virus pollution
Fecal coliforms : standard of EPA, 2 x 10^6/gTS for recycle of digested sewage sludge to farmland
Total coliforms : typical standard for wastewater discharge
Fecal streptococci : an indicator for microbiological safety in biogas plant proposed by Danish Government
Removal of the indicators by each step of the plant was investigated during the start-up period for 200 days. Furthermore, inactivation of the indicators in a mixture of caw manure and digested sludge was investigated at 37, 45, 55, 60, and 70℃, respectively.
All the indicators tended to decrease step wise through the plant. The fecal coliforms in the heat-inactivated sludge successfully achieved EPA standard. The removals of the indicators in the plant were in the order fecal coliforms>total coliforms>fecal streptococci>total coliphages. The indicators tended to decrease with time at each temperature. In activation of each indicator with temperature can be explained in Chick's law. This might be useful for the design of heat-inactivation process.
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