Aerobic denitrification of oligotrophic source water driven by reduced metal manganese. (March 2023) - Xue, Ruikang
Abstract: The lack of organic electron donors limits the potential utility of aerobic denitrification in treatment of oligotrophic source water. Here, reduced manganese (Mn) was used as an inorganic electron donor to improve the denitrification of oligotrophic source water under the high dissolved oxygen condition (7–9 mg L −1 ). Over 30 days, the total nitrogen removed by the treatment with reduced Mn was 76.21 ± 2.11% (maximum), substantially higher than that of the control treatment, which was 41.48 ± 2.33%. Furthermore, the addition of Mn resulted in the directional evolution of the microbial community. Water samples with Mn added showed a higher abundance of Limnohabitans, the dominant denitrifying genus, reaching 51.02%, 36.79%, and 20.19% (with 30, 50, and 70 g Mn, respectively), versus only 5.54% in the control. In biofilm, Mn promoted Hydrogenophaga and Brevundimonas growth while Pseudarthrobacter growth was promoted by 30 and 50 g Mn, but inhibited by 70 g Mn. This study demonstrates an improved performance in aerobic denitrification of water sources through the use of inorganic electron donors. Graphical abstract: Image 1 Highlights: Aerobic denitrification is hampered by the low C/N ratio of oligotrophic water. Reduced Mn compensates for the lack of organic electron donors in raw water. Addition of reduced Mn in source water treatment improves nitrogen removal. Reduced Mn leads to the directional evolution of microbial community structure. Inorganic electron donors can be employed in water quality improvement.