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Estimating Sediment Denitrification Rates Using Cores and N2O Microsensors
Published on: December 6, 2018
Partial Denitrification-Mediated anammox Evolution in anoxic Compartments: Deciphering metabolic activity and
Jianwei Li1, Yufei Wu1, Xiangchen Li2
1National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, China.
None:
The integration of partial denitrification (PD, NO3-→NO2-) with anaerobic ammonium oxidation (Anammox) in anoxic biofilm systems presents a transformative approach for enhanced nitrogen removal from municipal wastewater. Through a 7-month comparative analysis of spatially stratified anoxic zones in an anaerobic-anoxic-oxic bioreactor treating real wastewater (NH4+: 47.6 ± 4.7 mg N/L; COD: 154.8 ± 29.6 mg/L), this study achieved 71.8 ± 5.8% total nitrogen removal (effluent TN: 12.9 ± 3.9 mg N/L), aiming to propose optimization frameworks targeting biofilm carrier deployment in the anoxic zone. Test results showed that functional dominance partitioning emerged as a key determinant: the first anoxic zone (A1) exhibited peak anammox activity (0.034 kg N/m3/d) via rapid acetate-driven nitrate reduction, while the third zone (A3) sustained maximum Ca. Brocadia abundance (1.7%). Metagenomic sequencing further revealed that the highest ratio of NO3- reductase gene (narG) to NO2- reductase genes (nirS, nirK) was 2.06 in A3 compared to 1.39-1.68 in the other biofilms, indicating a stronger ability to supply NO2- to anammox. Carbon metabolic gene distribution revealed A1's acetate/glucose preference versus A3's endogenous metabolism dominance (elevated TCA cycle genes). This study proposes an innovative biofilm management framework for energy-efficient municipal wastewater treatment: front-positioned carriers maximize anammox nitrogen removal under moderate carbon-to-nitrogen ratios (3-5), while rear-positioned units secure anammox biomass retention during carbon surges.
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