| 摘要 |
PROBLEM TO BE SOLVED: To efficiently remove org. nitrogen by incorporating an nitrite into water contg. org. nitrogen such as urea which can not be removed by means of an ultrapure water production system. SOLUTION: A stock water such as industrial water is introduced into an NaNO2 injecting tank 3 through a pipeline 20 and a pipeline 21 provided with a stock water tank 1 and sodium nitrite (NaNO2 ) is injected therein from an NaNO2 tank through a pipeline 22. In this instance, the concn. of org. nitrogen is detected by means of an org. nitrogen analyzer 2 provided on the pipeline 20 and the org. nitrogen is efficiently removed by controlling the amt. of injection of NaNO2 based on this detected value. The water injected with NaNO2 in the injection tank 3 is then fed into a flocculation-solid-liq. separation means 5, wherein a flocculant is incorporated to perform solid-liq. separation. Then, the separated water is introduced from a tank 6 for separated water to a filter device 7 to store it in a tank 8 for the filtered water and then, ion exchange treatment is performed by means of an ion exchange pure water apparatus 9 and then, the org. nitrogen is removed by means of a reverse osmotic membrane separation apparatus 11. |
