| 摘要 |
PROBLEM TO BE SOLVED: To provide a nitrate nitrogen removing apparatus which is small in size of equipment and low in cost. SOLUTION: The apparatus which removes nitrate nitrogen in underground water to the standard value or less has a raw water tank 1, a raw water supply system 7 to the raw water tank 1, an electrodialyzer 2 that electrodialyzes the raw water supplied from the raw water tank 1 to remove the nitrate nitrogen, a generated water line 3, a bypass line 8 that returns a part of generated water to the raw water tank 1, a conductivity meter 10 that detects the electric conductivity of the generated water, a first flow control valve 11 on the generated line 7 and a second flow control valve 12 on the bypass line 8, and a controller 50 that controls the nitrate nitrogen concentration in the generated water introduced to the outside of a system at the standard or less by using the data of correlation between nitrate nitrogen concentration in the underground water and the electric conductivity, and controlling the first and second flow control valves 11, 12 based on the detection results of the conductivity meter 10 to adjust the circulation amount of the generated water circulating through the electrodialyzer 2. COPYRIGHT: (C)2004,JPO
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