| 摘要 |
In a water treatment system (1) that treats water to be treated by an activated sludge process, a mixed liquid of the water to be treated and the activated sludge flows from an oxygen-free tank (23) to an aerobic tank (24), and part of the mixed liquid that flows out of the aerobic tank (24) is returned to the oxygen-free tank (23) by a reflux pathway (41). The water treatment system (1) is provided with: a measurement means (92) that measures the nitrate-nitrogen concentration in the mixed liquid within the oxygen-free tank (23) or within the aerobic tank (24) or in the mixed liquid flowing between the oxygen-free tank (23) and the aerobic tank (24); a supply means (63) for supplying organic matter to the oxygen-free tank (23); and a control device (7) that controls the supply means (63). The control device (7) determines whether or not a change in the amount of organic matter supplied by the supply means (63) should be made on the basis of measurement values from the measurement means (92) for each of a fixed time interval, and when the determination is to change the amount of organic matter supplied, the supply means (63) is operated such that the amount of organic matter supplied is changed by a prescribed amount. |
