TY - JOUR
T1 - Effects of NaClO shock on MBR performance under continuous operating conditions
AU - Sun, Ming
AU - Hou, Bingdong
AU - Wang, Shengli
AU - Zhao, Qiannan
AU - Zhang, Lanhe
AU - Song, Lianfa
AU - Zhang, Haifeng
N1 - Publisher Copyright:
© The Royal Society of Chemistry.
PY - 2021/2
Y1 - 2021/2
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=85101175266&partnerID=8YFLogxK
U2 - 10.1039/d0ew00760a
DO - 10.1039/d0ew00760a
M3 - Article
AN - SCOPUS:85101175266
VL - 7
SP - 396
EP - 404
JO - Environmental Science: Water Research and Technology
JF - Environmental Science: Water Research and Technology
SN - 2053-1400
IS - 2
ER -