| 摘要 |
PROBLEM TO BE SOLVED: To optimally and automatically set the set value of waste ozone in the ozone treatment system of a water treatment process aiming at discoloration corresponding to chromaticity. SOLUTION: In controlling the concn. of waste ozone by diffusing ozone from an ozone generator 1 into an ozone contact tank 2 to react ozone with the raw water (sand filtered water) passing through the tank to treat the raw water with ozone and controlling the discharge power of the ozone generator 1 so as to reduce the amt. of the unreacted waste ozone gas, the set value of the concn. control of waste ozone corresponding to chromaticity 11 is automatically set by a controller 15. This setting is performed on the basis of the relation between the chromaticity of raw water capable of ensuring preliminarily experimentally calculated objective chromaticity and the set value of the concn. control of waste ozone. Therefore, the optimum set value of the concn. control of waste ozone can be automatically set. A PI controller 16 sets the concn. objective value of injection ozone from the moving average value of this set value and ozone concn. 13 and a PI controller 17 controls discharge power from the set value and injected ozone concn. 12.
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