Simultaneous nitrogen and phosphorus removal in water supply sludge biofilter: Focus on the impact of backwashing and microbial community analysis

• Published in: Process safety and environmental protection Vol. 189; pp. 1323 - 1332
• Main Authors: Gao, Yaoyao, Zeng, Daojing, Liu, Chao, Huang, Xiao
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.09.2024
• Subjects: Backwashing action; Denitrification biofilters; Functional metabolism; Microbial communities; Nitrogen and phosphorus removal; Backwashing action; Functional metabolism; Microbial communities; Nitrogen and phosphorus removal; Denitrification biofilters
• ISSN: 0957-5820
• DOI: 10.1016/j.psep.2024.07.024

The effect of backwashing on pollutant removal performance and microbial communities in the denitrification biofilter (DNBF) is a current research blind spot. Therefore, water supply sludge biofilters were constructed to investigate the effects of different backwashing conditions on nitrogen (N) and phosphorus (P) removal, and the microbial community structure and metabolic pathways were analyzed. Studies indicated that backwashing dislodged the biofilm and reduces pollutant removal. As the biofilm gradually rebuilt, the DNBF operation returned to normal. Chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) were removed at 60 %, 100 %, and 50 % after backwashing for 1 h with a 10 min air flush and 5 min water flush. Proteobacteria, Bacteroidetes and Firmicutes were easily enriched in the biofilm to act on pollutants during the process. Meanwhile, backwashing promoted Brevundimonas, while prolonged backwashing reduced the abundance of Chryseobacterium, Acinetobacter and Hyphomicrobium. This process affected microbial interactions and metabolism being the predominant functional classification. This study provides ideas for backwashing for pollutant removal in the DNBF. [Display omitted]