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J Environ Manage

Title:		Influence of polyelectrolyte architecture on the electrokinetics and dewaterability of industrial membrane bioreactor activated sludge
Author(s):		Yousefi SA; Nasser MS; Hussein IA; Judd S;
Address:		"Gas Processing Center, College of Engineering, Qatar University, P.O. Box 2713 Doha, Qatar. Gas Processing Center, College of Engineering, Qatar University, P.O. Box 2713 Doha, Qatar. Electronic address: m.nasser@qu.edu.qa"
Journal Title:		J Environ Manage
Year:		2019
Volume:		20181224
Issue:
Page Number:		410 - 416
DOI:		10.1016/j.jenvman.2018.12.067
ISSN/ISBN:		1095-8630 (Electronic) 0301-4797 (Linking)
Abstract:		"Improvement of sludge dewaterability is greatly hindered by the presence of large amounts of interstitial water molecules trapped in the sludge as a result of strong hydrophilic characteristics. This study has investigated the influence of six different polyacrylamide (PAM) flocculants with different molecular architecture (linear, slightly and highly branched), charge density (CD) and molecular weight (MW) on the electro-kinetics and dewatering of highly stable industrial membrane bioreactor (MBR) sludge. The impact of PAM on flocculation is manifested in the supernatant turbidity, particle zeta potential, sludge capillary suction time (CST), floc size and settleability. Turbidity removal and reduction in zeta potential are used to identify the optimum polymer dose. An optimum dose of 70?ª+mg.L(-1) has been determined for linear PAM of 40% CD. However, a highly-branched PAM, with the same CD, has shown an optimum value of 30?ª+mg.L(-1). In all cases, a turbidity removal of more than 99% and CST reduction of 51-64% is attained; the linear PAMs have resulted in the highest CST reduction. Higher PAM doses have resulted in larger flocs and the maximum particle size is observed at the saturation point. The reduction in sludge volume relates with the floc size and PAM dose. For sludge conditioning and dewaterability, highly branched PAM with low MW has shown superior performance over linear high MW PAM. Enhancement of flocculation and dewatering is correlated with the surface charge neutralization and bridging mechanisms"
Keywords:		Bioreactors Flocculation *Polyelectrolytes Sewage Water *Water Purification Activated sludge Charge density Membrane bioreactor Polyacrylamide Polyelectrolyte Volume reduction;
Notes:		"MedlineYousefi, Shiva A Nasser, Mustafa S Hussein, Ibnelwaleed A Judd, Simon eng England 2018/12/28 J Environ Manage. 2019 Mar 1; 233:410-416. doi: 10.1016/j.jenvman.2018.12.067. Epub 2018 Dec 24"