Chemical Cleaning-Triggered Release of Dissolved Organic Matter from a Sludge Suspension in a Ceramic Membrane Bioreactor: A Potential Membrane Foulant

Abstract

Ceramic membrane bioreactors (MBRs) have attracted a great deal of interest due to their robustness in the treatment of various kinds of wastewaters. So far, in situ chemical cleaning with sodium hypochlorite (NaClO) has been the most prevalent MBR cleaning method. This study showed that in situ NaClO cleaning in MBRs triggered a significant release of dissolved organic matter (DOM) from a sludge suspension, while the generated DOM could facilitate fouling development, especially irreversible fouling in a ceramic MBR. It was found that biopolymers with a molecular weight (MW) of >10 kDa and humic substances could be effectively rejected by the ceramic membranes. As such, the membrane fouling rate (dTMP/dt) of the supernatant from a NaClO-treated sludge suspension was closely related to the rejected levels of biopolymers and humic substances. However, hydrophobic DOM and low-MW organics (MW < 500 Da) could easily pass through the membranes, indicating an insignificant contribution to the observed membrane fouling. Consequently, this study verified the contributions of DOM released from a sludge suspension after in situ membrane cleaning with NaClO with respect to subsequent membrane fouling development in a ceramic MBR.

Bacteria and Virus Inactivation: Relative Efficacy and Mechanisms of Peroxyacids and Chlor(am)ine

“…Therefore, POAs may have promising potential in controlling cell lysis and IPS/ARG release. For example, free chlorine can trigger IPS release, which in turn leads to aggravated membrane fouling and DBP formation, during membrane cleaning of MBRs. ,, Thus, POAs that inactivate bacteria intracellularly should be considered for in situ membrane cleaning and biofouling control in MBRs. Moreover, UV/POAs may outperform UV/H 2 O 2 and UV/chlorine for pathogen inactivation, due to the photogeneration of radicals inside the cells, which has been demonstrated with PAA. ,, …”

Sustainable Recovery of Ionic Resources from Resin Regeneration Wastewater: Long-Term Evaluation, Membrane Fouling Analysis, and Cleaning

“…17,18 The physical, chemical, and electrical cleaning methods have been widely reported membrane cleaning methods. 19,20 According to the characteristics of different wastewaters, different cleaning methods are always chosen for recovering membrane fouling. For example, Guo et al proposed a chemical cleaning method of ion exchange membranes in plant-scale ED for treating oily wastewater.…”