Preparation and Dewatering Property of Two Sludge Conditioners Chitosan/AM/AA and Chitosan/AM/AA/DMDAAC

Two new chitosan-grafting copolymers (chitosan- g -PAM-AA and C-chitosan- g -PAM-AA) as sludge conditioners (flocculation and aggregation) have been prepared by employing ceric sulfate as a free radical initiator under nitrogen atmosphere in aqueous solution. The optimum condition for synthesizing chitosan-grafting copolymer was determined by orthogonal experiments. The structure, morphology and property of the obtained graft polymers were characterized by FT-IR, XRD, SEM, TGA and contact angle. Further, the municipal activated sludge dewatering performance of the synthesized copolymers was evaluated by the filter cake moisture content. Herein, the effects of pH value and dewatering temperatures of activated sludge, loading dosage or cationic degree of C-chitosan- g -PAM-AA on the filter cake moisture content were investigated. The synthesized amphoteric flocculant C-chitosan- g -PAM-AA showed a highly effective flocculation capability for activated sludge compared with chitosan- g -PAM-AA, chitosan, polyacrylamide (PAM). Also, the lowest filter cake moisture content was up to 61.41%.