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Effect of salinity on denitrification, membrane fouling and bacterial community in a fixed-bed biofilm membrane reactor

Authors :
Ning An
Lei Ma
Dameng Lian
Shuwei Wang
Source :
Water Science and Technology, Vol 89, Iss 5, Pp 1124-1141 (2024)
Publication Year :
2024
Publisher :
IWA Publishing, 2024.

Abstract

In this study, a fixed-bed biofilm membrane bioreactor was used to assess denitrification and carbon removal performance, membrane fouling, composition, and the dynamics of microbial communities across 10 salinity levels. As salinity levels increased (from 0 to 30 g/L), the removal efficiency of total nitrogen and chemical oxygen demand decreased from 98 and 86% in Phase I to 25 and 45% in Phase X, respectively. Beyond a salinity level of 10 g/L, membrane fouling accelerated considerably. The analysis of fouling resistance distribution suggested that soluble microbial products (SMPs) were the primary cause of this phenomenon. The irregularity in microbial community succession reflected the varying adaptability of different bacteria to different salinity levels. The relative abundance of Sulfuritalea, Lentimircobium, Thauera, and Pseudomonas increased from 20.2 to 47.7% as the experiments progressed. Extracellular polymeric substances-related analysis suggested that Azospirillum plays a positive role in preserving the structural integrity of the biofilm carrier. The SMP-related analysis showed a positive correlation between Lentimircobium, Thauera, Pseudomonas, and the SMP content. These results suggested that these three bacterial genera significantly promoted the release of SMP under salt stress, which in turn led to severe membrane fouling. HIGHLIGHTS Fixed-bed biofilm membrane bioreactor maintains good performance at low-salinity levels.; Soluble microbial products are the major cause for fixed-bed biofilm membrane bioreactor membrane fouling.; Azospirillum has a positive effect on carrier biofilms.; Lentimicrobium, Pseudomonas, and Thauera are highly correlated with soluble microbial product concentration.;

Details

Language :
English
ISSN :
02731223 and 19969732
Volume :
89
Issue :
5
Database :
Directory of Open Access Journals
Journal :
Water Science and Technology
Publication Type :
Academic Journal
Accession number :
edsdoj.66d69e3c8a55485e9a7c93d2c0a12161
Document Type :
article
Full Text :
https://doi.org/10.2166/wst.2024.050