1999 Fiscal Year Final Research Report Summary
Transformation of nitrogen and production of nitrous oxide in an estuary receiving treated wastewater
| Project/Area Number |
09450198
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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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 | KYUSHU UNIVERSITY |
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Principal Investigator |
KUSUDA Tetsuya Graduate School, Division of Engineering, Kyushu University, Professor, 大学院・工学研究科, 教授 (50037967)
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| Co-Investigator(Kenkyū-buntansha) |
YAMANISHI Hiroyuki Graduate School, Division of Engineering, Kyushu University, Research Associate, 大学院・工学研究科, 助手 (20240062)
OHISHI Kyoko Graduate School, Division of Engineering, Kyushu University, Research Associate, 大学院・工学研究科, 助手 (20110835)
KUBA Takahiro Graduate School, Division of Engineering, Kyushu University, Associate Professor, 大学院・工学研究科, 助教授 (60284527)
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| Project Period (FY) |
1997 – 1999
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| Keywords | Treated wastewater / Estuary / Transformation of nitrogen / Nitrous oxide / Field survey / Nitrification / Denitrification / Dissolved oxygen |
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| Research Abstract |
Transformation of nitrogen compounds and the production of NィイD22ィエD2O were investigated in an estuary, the Tatara estuary in Fukuoka, receiving the load from two wastewater treatment plant. Conclusions obtained in this study are as follows :
1) Loading from the wastewater treatment plants to the estuary brings severe impacts through the production of NィイD22ィエD2O ;
2) Nitrous oxide originated from treated wastewater and sediments ;
3) The major production sites of NィイD22ィエD2O in sediments were in the midstream of the Tatara estuary ;
4) Nitrification is a possible source of NィイD22ィエD2O especially in low temperature season ;
5) The highest concentrations of NィイD22ィエD2O in water bodies at the observation stations raged from 1.8 to 20.9μM ;
6) Nitrous oxides has been oversaturated in the water bodies and sediments and its flux to the atmosphere is about 1.07 MmolNkmィイD1-2ィエD1yィイD1-1ィエD1 in this estuary ;
7) The emission rate of NィイD22ィエD2O to the atmosphere is as same order of magnitude as its net production rate in the estuary ;
8) The temporal increases in production rate of NィイD22ィエD2O were found in the denitrification process following the onset of anaerobic conditions ;
9) When temperatures in the culture was shifted up, the temporal increase of NィイD22ィエD2O in production rates were found.
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