Polyacrylamide as coagulant aid with polytitanium sulfate in humic acid-kaolin water treatment: Effect of dosage and dose method

This study focused on the application of polyacrylamide (PAM) as a coagulant aid of polytitanium sulfate (PTS) in humic acid-kaolin water treatment. Coagulation performance and floc properties were all measured in terms of dose amount and dose sequence of PAM and PTS which is meaningful for the practical application. Results showed that PTS-PAM (PTS dosed firstly) attained better natural organic matter (NOM) removal and PAM-PTS (PAM dosed firstly) attained better turbidity removal. Floc size was significantly enhanced by the PTS-PAM, while floc size of PAM-PTS attained similar size as that of PTS alone. Floc strength and recovery ability were also significantly improved by PTS-PAM. Moreover, PTS-PAM floc had a looser structure than that of PTS, while PAM-PTS floc and PTS floc had similar and more compact structure. The effect of PAM on the sludge reuse process was also studied. Results showed that the addition of PAM had a positive effect on the photocatalytic activity of sludge prepared TiO2. (C) 2016 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.