| Project/Area Number |
11558074
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 展開研究 |
|---|
| Research Field |
環境保全
|
|---|
| Research Institution | KANAZAWA UNIVERSITY |
|---|
Principal Investigator |
KAWANISHI Takuya KANAZAWA UNIV, GRAD. SCHOOL SCI. & ENG, ASSOC. PROFESSOR, 自然科学研究科, 助教授 (80234087)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
FUKUURA Kiyoshi MAEZAWA INDUSTRIES, INC. TECHNICAL SECT. MAANAGER, 土壌環境部, 技術課長(研究職)
HANAKI Keisuke UNIV. TOKYO, GRAD. SCHOOL ENG. PROFESSOR, 大学院・工学系研究科, 教授 (00134015)
HAYASHI Yoshishige KANAZAWA UNIV DEPT. CHEM. CHEM ENG, PROFESSOR, 工学部, 教授 (60019750)
|
|---|
| Project Period (FY) |
1999 – 2001
|
| Project Status |
Completed (Fiscal Year 2001)
|
| Budget Amount *help |
¥9,700,000 (Direct Cost: ¥9,700,000)
Fiscal Year 2001: ¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 2000: ¥4,100,000 (Direct Cost: ¥4,100,000)
Fiscal Year 1999: ¥3,700,000 (Direct Cost: ¥3,700,000)
|
|---|
| Keywords | NITRATE / REMOVAL / SOIL / DENITRIFICATION / SULFUR / PERMEABILITY / GAS DIFFUSION / ANOXIC / 地下水 / 浸透水 / 脱窒 / 拡散係数 / 硫黄脱窒 / 透水係数 / 窒素除去 / 保水性 / 酸素拡散速度 / 窒素 / 酸素供給 / モデル |
|---|
| Research Abstract |
The objective of this research is to develop a method for removing nitrate directly from soil percolate. We construct a low permeability layer (LPL) below the level where nitrogen is sufficiently nitrified. By "low permeability layer" we mean the soil layer whose saturated hydraulic conductivity is approximately equal to the infiltration rate of the site. As the water percolates in the soil, LPL becomes saturated and acts as a barrier to oxygen supply. In addition, we put electron donor for denitrification, such as sulfur, etc. below the LPL. Thus, below LPL, oxygen concentration will be suppressed and there exist electron donors, then denitrification will occur. Two soil columns of 0.15 m in diameter and 0.8 m in height are prepared. For the one column (LPL column) we set LPL whose saturated hydraulic conductivity is approximately 0.1 m d^<-1>(20℃) at depth from 0.16 to 0.32 m. Below the LPL, sulfur (electron donor) and calcium carbonate was added to the soil in a (mass) ratio of S : CaC0_3 : soil = 5 : 5 : 90, at depths from 0.32 to 0.48 m. For the other (control) column, LPL is not prepared but sulfur and calcium carbonate was added to the soil in the same ratio at the same depths. Potassium nitrate solution of 20 mg-N∫^1 was supplied from the top of the column continuously at several different rates.
In a 3-month experiment, LPL column revealed apparent nitrate removal efficiency of 0.79, 0.84 and 0.94 for the water feed rates of 0.025, 0.05 and 0.1 m d^<-1>, respectively. Thus, we concluded this Low Permeability Layer Oxygen Barrier method really works.
|
