Drainage of the processing device, method of processing waste water and drainage of the processing system, as well as the control device, control method, and program

Performing a biological treatment to be treated water flowing through the aerobic tank 2a~2d that make up the reaction vessel 2. Air is supplied to the reaction vessel 2 from each of the spraying component 6a~6d with each of the aerobic tank 2a~2d, aerating the water to be treated. The first and second predetermined position for each nitrate meter 7a along the flow of the water to be treated in the reaction vessel 2, the provided 7 b, to measure the nitric acid concentration of the respective positions. Nitric acid meter 7a, 7b provides a measured value of the nitric acid concentration of each of the predetermined position to the control unit 9. Controller 9 based on the measurement values ​​of nitrate concentration, all as nitric acid concentration at a predetermined position is within any set target range, and supplies a control signal to the gas supply amount control unit 10a~10d spraying component to control the gas supply amount from the 6a~6d.