| 摘要 |
PURPOSE:To prevent defective addition of a chemical even to an area where serious variation of the concn. of sludge is occuring and to stabilize the operation of a plant thus to reduce the running cost by deciding the amt. of the chemical to be added basing on the solid quantity and concentration of the sludge. CONSTITUTION:A flow rate and concn. of sludge fed from a sludge tank 1 to a dehydrator 2 are measured, and the measured values are inputted to an operator 6, and the quantity of solid in the sludge is calculated by the operator 6. The calculated value of the solid quantity in the sludge and the measured value of the concn. of the above-described sludge are inputted in an operator 7, and the quantity of a chemical to be fed to a dehydrator 2 is calculated by the operator 7 basing on the solid quantity and concn. of the sludge. A pump 9 for feeding the chemical from a chemical tank 8 to the dehydrator 2 is controlled basing on the calculated value. As described above, the quantity of the chemical to be added is decided taking the concn. of the sludge also into consideration, defective addition of the chemical is not caused even in an area where serious variation of the concn. of the sludge is caused. Therefore, stabilization of the operation of the plant and reduction of the running cost are realized.
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