| 摘要 |
PROBLEM TO BE SOLVED: To provide a means for demanding no increase of the amount of a polymer flocculant to be added as a method for efficiently dehydrating sludge having low fiber content even when an inorganic flocculant is not used at the same time, since the general means for restraining a cost increase owing to the increase of the amount of the polymer flocculant to be added is to use the inorganic flocculant at the same time but the use of the inorganic flocculant causes an increase of dehydrated sludge and arouses the concern of a bad influence on the environment or the health. SOLUTION: The method for dehydrating sludge comprises the steps of: adding a water-soluble cationic polymer to the sludge the pH value of which is 5-8; adding a water-soluble amphoteric polymer to the cationic polymer-added sludge; and dehydrating the amphoteric polymer-added sludge. The water-soluble cationic polymer has 50-90% charge inclusion rate to be defined in the patent. COPYRIGHT: (C)2010,JPO&INPIT
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