Method for preventing the bulking of activated sludge

Abstract

A method for preventing the bulking of activated sludge, which comprises adding to the activated sludge a water-soluble cationic polymer obtained by a reaction of a dialkylamine with epichlorohydrin, in an amount of from 0.1 to 25 parts by weight relative to 100 parts by weight of the dried solid content of the activated sludge.

I claim: 
     
       1. A method for preventing the bulking of activated sludge, which comprises adding to the activated sludge a water-soluble cationic polymer having a intrinsic viscosity of .[.at least.]. .Iadd.from .Iaddend.0.05 .Iadd.to 0.26 .Iaddend. as measured in a 2M K BR aqueous solution obtained by the reaction .Iadd.consisting essentially .Iaddend.of a dialkylamine with epichlorohydrin, in an amount of from 0.1 to 25 parts by weight relative to 100 parts by weight of the dried solid content of the activated sludge.   
     
     
       2. The method for preventing the bulking of activated sludge according to claim 1, wherein the water soluble cationic polymer is selected from those having an intrinsic viscosity of .[.at least.]. 0.1 .Iadd.to 0.26 .Iaddend.is measured in a 2M KBr aqueous solution. 
     
     
       3. The method for preventing the bulking of activated sludge according to claim 1, wherein the dialkylamine is dimethylamine, diethylamine, dipropylamine, methylethylamine, methylpropylamine or ethylpropylamine. 
     
     
       4. The method for preventing the bulking of activated sludge according to claim 1, wherein the water-soluble cationic polymer is added in an amount of from 0.5 to 10 parts by weight relative to 100 parts by weight of the dried solid content of the activated sludge.