Wastewater treatment system, air supply amount control device, and air supply amount control method

A control method of a water treatment system including:

• a plurality of reaction tanks configured to perform biotreatment on water to be treated;
• a blowing pipe and an in-pipe pressure measurement unit, which measures a pressure in the blowing pipe, connected with the plurality of reaction tanks;
• a blower unit configured to supply air for performing the biotreatment to the plurality of reaction tanks through the blowing pipe;
• a target in-pipe pressure calculation unit, which is a computing apparatus, configured to calculate pressure losses in the blowing pipe based on a change in a necessary amount of air for performing the biotreatment on the water to be treated;
• and a blowing control unit, which is a computing apparatus, connected to the in-pipe pressure measurement unit and the blower unit, the method comprising:
• performing a blowing control step to control an amount of air supplied from the blower unit so that a pressure in the blowing pipe, which is measured by the in-pipe pressure measurement unit, becomes equal to a target in-pipe pressure,
• determining, in the blowing control step, the target in-pipe pressure for each of the plurality of reaction tanks, in the blowing control unit, based on a necessary amount of air for performing the biotreatment in each of the plurality of reaction tanks and a pressure loss in the blowing pipe in a case where the necessary amount of air is supplied into the blowing pipe, and
• setting the target in-pipe pressure of the blowing pipe, in the blowing control unit, based on the necessary amount of air for each of the plurality of reaction tanks, and controlling, in the blowing control unit, the amount of air supplied from the blower unit, wherein
• the blowing pipe includes a header pipe connected with the blower unit, a plurality of branch pipes branched from the header pipe and connected with the reaction tanks, respectively, with the in-pipe pressure measurement unit operable for measuring pressure in the header pipe and the target in-pipe pressure calculation unit operable for calculating a pressure loss at each of the plurality of branch pipes, and
• the target in-pipe pressure of the header pipe is set, in the blowing control unit, based on the pressure loss at each of the plurality of the branch pipes as calculated by the target in-pipe pressure calculation unit.