Fe3+ augmentation enhancing the nitrogen and phosphorus control in denitrification biofilter based on water supply sludge: Performance and microbial characteristics

• Published in: Journal of environmental chemical engineering Vol. 12; no. 5; p. 114002
• Main Authors: Gao, Yaoyao, Yan, Xiaofei, Huang, Xiao
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.10.2024
• Subjects: Denitrification biofilter; Functional metabolism; Iron ions; Microbial community; Nitrogen removal; Phosphorus removal; Nitrogen removal; Functional metabolism; Denitrification biofilter; Phosphorus removal; Iron ions; Microbial community
• ISSN: 2213-3437
• DOI: 10.1016/j.jece.2024.114002

The intricate mechanisms of iron (Fe) enhancing the simultaneous nitrogen (N) and phosphorus (P) removal in the denitrification biofilter (DNBF) remain enigmatic and warrant further investigation. Fe2+ and Fe3+ were added to compare the enhancing performances and the dosage concentration was optimized in this study, and the effects of Fe3+ on microbial characteristics were elucidated furtherly. Results demonstrated that the N removal performance with Fe3+ enhancing was better than Fe2+, and the optimal FeCl3 concentration was 0.56 mg/L. The effluent concentrations of total phosphorus (TP), total nitrogen (TN), and chemical oxygen demand (COD) lowed to 0.27, 4.2, and 13.4 mg/L, respectively. Fe3+ promoted microbial richness and diversity, with Proteobacteria, Bacteroidetes and Firmicutes emerging as the advantageous phyla for N and P removal in the DNBF. Microorganisms facilitated Fe3+ reduction to enhance denitrification process, and P was predominantly removed through the precipitation formed by the interaction of Fe and P. Furthermore, Fe3+ was noted to promote functional metabolism, thereby aiding in N removal. This study can reveal the effect of Fe3+ on N removal in the DNBF, and provide a theoretical foundation for advanced N and P removal. •Microbial diversity and richness changed with Fe3+ addition.•Fe3+ promoted denitrification and inhibited nitrification.•Microbial function prediction was influenced by Fe3+.•Metabolism was the main functional classification.