| 摘要 |
PURPOSE:To improve the treatment efficiency by controlling the amt. of air to be delivered and the total amt. of sludge to be retained within the limits where a nitration reaction does not occur to save the power cost of a blower, and preventing the flotation of sludge in a settling pond. CONSTITUTION:An oxygen utilizing velocity measured by a device 16, the amt. of air delivered from a blower 6, the sludge concn. at the outlet of an aeration vessel 2 and the preset upper and lower values of the blower output outputted from an on-line simulator 20, and the standard value of the oxygen utilizing velocity by removing BOD per unit weight of sludge are inputted to an arithmetic unit 21, and the set value of the dissolved oxygen concn. in the aeration vessel and the set value of the total amt. of sludge -to be retained in the system are calculated. The set value of the dissolved oxygen concn. outputted from the unit 21 and the actual dissolved oxygen concn. are compared in a blast amt. controller 22, and the blast amt. is controlled so that the actual disolved oxygen concn. may be regulated to the set value. The set value of the total amt. of sludge to be retained outputted from the unit 21 and the total amt. of sludge to be retained calculated in the simulator 20 are compared in a controller 23 for contr-olling the total amt. of sludge to be retained, and the discharge of excess sludge is controlled so that the values may be equalized.
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