| 摘要 |
PURPOSE:To dehydrate sludge with less operating labor and good efficiency by measuring the air permeability of an endless traveling filter cloth either after stripping cake therefrom or after washing the filter cloth and controlling a chemical feed rate, washing water amt., etc. according to the measured value thereof. CONSTITUTION:Sludge 11 generated in a sewage treatment plane, etc. is added with chemicals such as a flocculating agent, etc. in a thickening stage, etc. and thereafter the sludge is introduced to a thickening part A of a roll press dehydrator provided with an endless traveling filter cloth 5. The sludge 11 dewatered by a gravity effect in said part is compressed and dehydrated between the filter cloth 5 and other filter cloth 6 in a compression dehydrating part B. The sludge is then stripped as cake by a scraper 7 from the filter cloth in a cake stripping part C. The cloth 5 is thereafter washed in a filter cloth washer 8 and is returned again to the part A. The air permeability of the cloth 5 after the washing is measured with a detector 1. At least one among the amt. of washing water, chemical feed rate, the rate of the sludge to be supplied, the traveling speed of the filter cloth, the tension on the filter cloth, the agitating speed in the stage for flocculating the sludge, etc. is controlled in accordance with the difference in the air permeability between the measured value and the air permeability of the cloth 5 in the unused state. |
