Treatment of pulp and paper mill wastewater with various molecular weight of polyDADMAC induced flocculation

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 166; no. 2; pp. 529 - 535
• Main Authors: Razali, M.A.A., Ahmad, Z., Ahmad, M.S.B., Ariffin, A.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier B.V 15.01.2011; Elsevier
• Subjects: Applied sciences; Chemical engineering; Chlorides; Crack opening displacement; Exact sciences and technology; Flocculating; Flocculation; General purification processes; Liquid-liquid and fluid-solid mechanical separations; Mills; mixing; Molecular weight; neutralization; Pollution; PolyDADMAC; Polyelectrolyte; pulp and paper mills; Reduction; Settling; total suspended solids; turbidity; Waste water; wastewater; Wastewater treatment; Wastewaters; Water treatment and pollution; Zeta potential; Polyelectrolyte; PolyDADMAC; Zeta potential; Flocculation; Mixing; Chemical oxygen demand; Turbidity; Electrokinetic potential; Sedimentation; Waste water; Paper industry; Neutralization
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2010.11.011

The flocculation performances of different molecular weight of polydiallyldimethylammonium chloride (polyDADMAC) in the treatment of pulp and paper mill wastewater were studied. The molecular weights used were 8.5×104, 8.8×104, 10.5×104 and 15.7×104g/mol. The flocculation performance test was carried out in jar tests with polyDADMAC dosages ranging from 0.4 to 2.0mgL−1. The test was conducted with rapid mixing at 200rpm for 2min, followed by slow mixing at 40rpm for 10min and a settling time of 5min. The effectiveness of the flocculation was measured based on the reduction of the turbidity, the total suspended solids (TSSs), chemical on demand (COD) reduction and zeta potential measurements. It was found that the flocculation performance of higher molecular weight samples was more efficient compared with that of lower molecular weights. This might be due to the bridging mechanism, which occurred concurrently with the charge neutralization effect during flocculation.