The present disclosure generally relates to dewatering aqueous sludge that is produced by waste water or sewage treatment facilities such as from municipal and industrial processes. The method includes treating an aqueous sludge with a cationic polyacrylamide terpolymer that includes an acrylamide; a first cationic monomer and a second cationic monomer that is different from the first monomer, and dewatering the treated aqueous sludge.