| 摘要 |
PROBLEM TO BE SOLVED: To discuss and propose physical properties which a dehydrating agent comprising a water-soluble polymer should have, when so-called hardly dehydratable sludge of a low fiber content such as digested sewage sludge in a sewage treatment plant is dehydrated with the dehydrating agent by using a screw press type or rotary press type dehydrator. SOLUTION: The water-soluble polymer has a charge inclusion ratio of 50% or more and 90% or less and is represented by the following definition. A water-soluble polymer obtained by polymerizing a mixture comprising monomers essentially containing a monomer having a specified structure and a structure modifier is used as the water-soluble polymer to achieve the sludge hydration. Definition: In the case of a water-soluble cationic polymer and a water-soluble amphoteric polymer having a positive difference between a copolymerization rate of a cationic monomer and a copolymerization rate of an anionic monomer, the charge inclusion ratio [%]=(1-α/β)×100, whereinαis a titer obtained by titrating an aqueous solution of the water-soluble cationic polymer or amphoteric polymer whose pH has been adjusted to 4.0 by acetic acid with an aqueous solution of polyvinyl potassium sulphonate;βis a titer obtained by subtracting a titer, obtained by adding the aqueous solution of polyvinyl potassium sulphonate of the amount sufficient to neutralize the charge of the water-soluble cationic polymer or amphoteric polymer to the aqueous solution of the water-soluble cationic polymer or amphoteric polymer whose pH has been adjusted to 4.0 by acetic acid and then titrating the mixture with an aqueous solution of polydiaryl dimethyl ammonium chloride, from a blank value. COPYRIGHT: (C)2010,JPO&INPIT |
