| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a method which can immediately cope with a deterioration in settlability of activated sludge and surely promote the settling of activated sludge in a waste liquid treatment method where a mixed liquid is introduced to a settling tank to be settled and separated and a part of separated sludge is returned to an aeration tank in activated sludge processing for introducing the waste liquid to the aeration tank retaining activated sludge to biologically treat it. <P>SOLUTION: In the waste liquid treatment method where a mixed liquid is introduced to a settling tank to be settled and separated and a part of separated sludge is returned to an aeration tank in activated sludge processing for introducing the waste liquid to the aeration tank retaining activated sludge to biologically treat it, a water-soluble polymer having an amidine structure, which can be produced by carrying out the Hofmann reaction of a copolymer of (meth)acrylamide and (meth)acrylonitrile, and then subjecting it to neutralization with an acid and heating treatment is added to a passage from the aeration tank to the settling tank as a precipitant. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
