Effects of NaClO shock on MBR performance under continuous operating conditions

Ming Sun, Bingdong Hou, Shengli Wang, Qiannan Zhao, Lanhe Zhang, Lianfa Song, Haifeng Zhang

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

In situ chemical cleaning with sodium hypochlorite (NaClO) is frequently employed to maintain a constant permeability in membrane bioreactor (MBR) systems. In this study, the effects of NaClO shock on MBR performance under continuous operating conditions were investigated. A lab-scale MBR was operated for three runs with in situ chemical cleaning. Experimental results demonstrate an obvious increase of the membrane fouling rate (13.7, 23.5 and 23.3 kPa d-1) on day 1 of cleaning, followed by a rapid reduction (6.4, -0.2 and 3.5 kPa d-1) on day 2 of cleaning. This indicates the rapid self-recovery ability of the NaClO-shocked sludge. Furthermore, as the operating time increased, the sludge extracellular polymeric substance (EPS) content initially increased, followed by a subsequent decrease, with the gradual improvement of sludge filterability that consequently reduced membrane fouling. Thermodynamic analysis revealed that the shocked-sludge surface properties, including the surface electron donor component (γ-), hydrophobicity, adhesive energy and self-cohesive ability, were gradually restored to the raw sludge level, which reduced the membrane fouling potential.

Original languageEnglish
Pages (from-to)396-404
Number of pages9
JournalEnvironmental Science: Water Research and Technology
Volume7
Issue number2
DOIs
StatePublished - Feb 2021

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