| 摘要 |
PROBLEM TO BE SOLVED: To realize, on an occasion for treating nitrogen-containing water through a plurality of reaction tanks of an identical style connected in parallel, a treatment precision similar to that of a case where expensive nitric acid meters are used without using the nitric acid meters within all reaction tanks.SOLUTION: Nitrogen-containing water is fed through a plurality of reaction tanks at an identical flow rate, and not only is aeration controlled within a zone of any one of the plurality of reaction tanks including an upstream zone on the basis of results of measurements by a nitric acid meter(s) configured at a midway position of the reaction tank or at first through n-th specified positions in such a way that optimal denitrification and nitrification will be executed within the corresponding reaction tank but aeration levels of the other reaction tanks are also controlled by setting, based on the dissolved oxygen content measured at a specified position of the corresponding reaction tank, the goal value of the dissolved oxygen content at an identical position of the other reaction tanks. |
