In-depth insight into improvement of simultaneous nitrification and denitrification/biofouling control by increasing sludge concentration in membrane reactor: performance, microbial assembly and metagenomic analysis
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Updated: Jun 22, 2026

Electrochemically and Bioelectrochemically Induced Ammonium Recovery
Published on: January 22, 2015
Rui Huang1, Mingyue Geng2, Shanshan Gao2
1School of Civil and Transportation Engineering, Hebei University of Technology, Tianjin 300401, China; Guangdong GDH Water Co. Ltd, Shenzhen 518021, China; School of Environment, Harbin Institute of Technology, Harbin 150090, China.
Abstract:
Currently, severe membrane fouling and inefficient nitrogen removal were two main issues that hindered the sustainable operation and further application of membrane bioreactor (MBR). This study aimed to simultaneously alleviate membrane fouling and improve nitrogen removal by applying high sludge concentration in MBR. Results showed that high sludge concentration (12000 mg/L) enhanced total nitrogen removal efficiency (78 %) and reduced transmembrane pressure development rate. Microbial community analysis revealed that high sludge concentration enriched functional bacteria associated with nitrogen removal, increased filamentous bacteria fraction in bio-cake and inhibited Thiothrix overgrowth in bulk sludge. From molecular level, the key genes involved in nitrogen metabolism, electron donor/adenosine triphosphate production and amino acid degradation were up-regulated under high sludge concentration. Overall, high sludge concentration improved microbial assembly and functional gene abundance, which not only enhanced nitrogen removal but also alleviated membrane fouling. This study provided an effective strategy for sustainable operation of MBR.
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