Related Experiment Video
Updated: Aug 21, 2026

Electrochemically and Bioelectrochemically Induced Ammonium Recovery
Published on: January 22, 2015
High Mn(II) drives Mn cycling to enhance solid-phase denitrification rate for treating nitrate-contaminated
Qi Zhou1, Wangmi Chen2, Xiuwei Ao1
1School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, PR China.
Abstract:
Understanding of the influence of coexisting Mn(II) on solid-phase denitrification (SPD) systems in treating nitrate-contaminated groundwater remains limited. This study investigated the impact of different Mn(II) concentrations on the performance and mechanisms of sawdust-based SPD systems for treating nitrate-contaminated groundwater within 106 days. The SPD systems still maintained high nitrate removal efficiency (>99 % within 48 h) with Mn(II) addition. Surprisingly, 10 mg/L Mn(II) improved denitrification rates, and enhanced PO43--P and DOC removal while Mn(II) itself was not eliminated. Kinetic modeling confirmed that first-order and Gompertz models effectively (R2 > 0.91) predicted nitrate removal under varying Mn(II) concentrations. XPS confirmed the coexistence of Mn(II), Mn(III), and Mn(IV), supporting an active Mn(II) redox process. Microbial community shifts under high Mn(II) favored Firmicutes over Proteobacteria. 10 mg/L Mn(II) promoted enrichment of hydrolysis/fermentative bacteria (Bacteroidetes_vadinHA17), spore-forming/Mn-oxidizing bacteria (unclassified_f__Sporomusaceae), and Mn-reducing bacteria (Paludibaculum and Anaerovorax), revealing that the dual role of high Mn(II) in promoting supply of biomass carbon sources and enhancing Mn redox cycle. Differential functional gene analysis revealed that 10 mg/L Mn(II) stimulated the TCA cycle, electron transfer, and denitrifying enzymes for enhancing denitrification. Mn(II) oxidation was primarily mediated by Fe-Mn superoxide dismutase (Fe-MnSOD) within spore-forming bacteria, whereas MnOx reduction was driven by flagellar and pili and electron shuttles (riboflavin and heme). Based on these findings, we proposed a mechanism driven by 10 mg/L Mn(II), beyond which Mn cycling continuously facilitates N removal. These insights offer a new insight into the Mn redox cycle, contributing to the optimization of sawdust-based SPD systems for groundwater remediation.
More Related Videos
08:05Measurement of the Potential Rates of Dissimilatory Nitrate Reduction to Ammonium Based on 14NH4+/15NH4+ Analyses via Sequential Conversion to N2O
Published on: October 7, 2020
10:29A Microfluidic Platform to Investigate Microbial Precipitation of Metal Oxides in Porous Media
Published on: June 12, 2026
Related Concept Videos
Microbial Wastewater Treatment
Microbial Bioremediation of Uranium
Acid Mine Drainage
Microbial Leaching
Inorganic Nitrogen Assimilation
Microbial Fuel Cells