Pre-coagulation for membrane fouling mitigation in an aerobic granular sludge membrane bioreactor: A comparative study of modified microbial and organic flocculants

This mini-review reports the effect of aerobic granular sludge (AGS) on performance and membrane-fouling in combined aerobic granular sludge–membrane bioreactor (AGS–MBR) systems. Membrane-fouling represents a major drawback hampering the wider application of membrane bioreactor (MBR) technology. Fouling can be mitigated by applying aerobic granular sludge technology, a novel kind of biofilm technology characterized by high settleability, strong microbial structure, high resilience to toxic/recalcitrant compounds of industrial wastewater, and the possibility to simultaneously remove organic matter and nutrients. Different schemes can be foreseen for the AGS–MBR process. However, an updated literature review reveals that in the AGS–MBR process, granule breakage represents a critical problem in all configurations, which often causes an increase of pore-blocking. Therefore, to date, the objective of research in this sector has been to develop a stable AGS–MBR through multiple operational strategies, including the cultivation of AGS directly in an AGS–MBR reactor, the occurrence of an anaerobic-feast/aerobic-famine regime in continuous-flow reactors, maintenance of average granule dimensions far from critical values, and proper management of AGS scouring, which has been recently recognized as a crucial factor in membrane-fouling mitigation.

Download Full-text

Reactor performance and membrane fouling of a novel submerged aerobic granular sludge membrane bioreactor during long-term operation

Journal of Water Reuse and Desalination ◽

10.2166/wrd.2017.019 ◽

2017 ◽

Vol 9 (1) ◽

pp. 1-9 ◽

Cited By ~ 1

Author(s):

Jianfeng Li ◽

Yanjun Liu ◽

Xiaoning Li ◽

Fangqin Cheng

Keyword(s):

Membrane Fouling ◽

Membrane Bioreactor ◽

Sewage Treatment ◽

Granular Sludge ◽

Synthetic Wastewater ◽

Aerobic Granular Sludge ◽

Municipal Sewage ◽

Reactor Performance ◽

Term Operation

Abstract The aerobic granular sludge membrane bioreactor (AGS-MBR) has the potential for simultaneous carbon/nitrogen removal and membrane fouling mitigation. Most studies have focused on comparison of granular sludge MBR and flocculent sludge MBR in short-term tests using synthetic wastewater. In this study, two identical AGS-MBRs were developed, and the reactor performance and membrane fouling were examined systemically over 120 days for synthetic wastewater and municipal sewage treatment, respectively. Results showed that regular granules with good settling ability were developed and maintained throughout the experimental period. Regardless of the substrate type, AGS-MBR demonstrated a stable removal of carbon (85–95%) and nitrogen (50–55%) in long-term operation. In addition, the membrane fouling propensity is apparently lower in AGS-MBRs with no membrane cleaning for 4 months at a flux of 20 L m−2h−1. The filtration resistance analysis indicates that the main membrane resistance was caused by irreversible fouling in both of the reactors. Membrane foulant analysis indicates that proteins in extracellular polymeric substances are more prone to be attached by the membrane of AGS-MBRs because of their hydrophobic nature. This study shows that AGS-MBR is effective and stable for municipal sewage treatment and reuse during long-term operation.

Download Full-text