| 摘要 |
<p>Disclosed is a process of dewatering an aqueous suspension, in which the aqueous suspension is a sewage sludge, comprising (a) dosing the suspension with a flocculating amount of a first flocculant, in which the first flocculant is a cationic organic acrylamide polymer of a molecular weight of at least one million, to form a thickened suspension involving initial flocculation and the release of free water, (b) introducing and mixing into the thickened suspension a dewatering amount of a second flocculant, in which the second flocculant is selected from cationic polyacrylamides in which the intrinsic viscosity is between 4 dl/g and 10 dl/g, or a polymer formed from 50 to 100% by weight methyl chloride quaternary ammonium salt of dimethyl amino ethyl (meth) acrylate and 0 to 50% by weight acrylamide of intrinsic viscosity between 4 dl/g and 10 dl/g, and (c) subjecting the thickened suspension to mechanical compression dewatering to form a cake, wherein the second flocculant comprises a water-soluble or water swellable polymer that is mixed into the suspension in the form of (i) substantially dry polymer particles having a weight average particle diameter of at least 50 microns or (ii) an aqueous composition comprising dissolved or hydrated polymer having a polymer concentration of at least 2% by weight.</p> |
