Treatment of Pulp and Paper Mill Wastewater with Various Molecular Weight of PolyDADMAC Induced Flocculation with Polyacrylamide in the Hybrid System

Flocculation studies between dual polymers on pulp and paper mill wastewater are reported in this paper. The effects of different molecular weights of polyDADMAC and different dosages of Polyacrylamide (PAM) were studied. The molecular weights of polyDADMAC used were 8.8 × 10, 10.5 × 10 and 15.7 × 10 g/mol. The flocculation performance was analyzed in jar tests with PolyDADMAC and Polyacrylamide dosages ranging from 0.4 2.0 mg·L and 0.4 8.0 mg·L respectively. A higher molecular weight and a 6.0 mg·L dosagepolyDADMAC gave the highest level of flocculation based on turbidity and TSS removal. In addition, increasing the molecular weight of PolyDADMAC increased ζ potential values approaching zero. This indicated that polyDADMAC acts as a destabilizer. Based on TSS, the addition of PAM will improve the size of microflocs created by polyDADMAC. It demonstrates that PAM acts as a bridger between microflocs.