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| Inexpensive Composite Filler Coupled with Heterotrophic Nitrification-Aerobic Denitrification Bacteria to Treat Nitrogen Pollution from Groundwater in Rare Earth Mines：Removal Efficiency and Mechanism |
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Received:November 15, 2024
Revised:December 07, 2024
Accepted:December 09, 2024
Published Online:April 19, 2025
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| DOI：doi：10.20237/j.issn.1007-7545.2025.05.020 |
| KeyWord:rare earth mine groundwater; nitrogen remediation; heterotrophic nitrification-aerobic denitrification; composite filler; microbial community structure |
| Author | Institution |
| WU Junzhe |
东华理工大学水资源与环境工程学院 |
| SONG Yong |
江西省地质局有色地质大队 |
| JIANG Tao |
江西省地质局有色地质大队 |
| XUAN Keng |
东华理工大学，水资源与环境工程学院 |
| WU Linwei |
江西省地质局有色地质大队 |
| WANG Shiqi |
湖南省地球物理地球化学调查所 |
| ZHONG Jiale |
东华理工大学水资源与环境工程学院 |
| GAO Bai |
东华理工大学，水资源与环境工程学院 |
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| Abstract: |
| The extraction of rare earth elements through the ammonium sulfate leaching process has resulted in significant nitrogen pollution in the groundwater of rare earth mines. Address to the characteristics of groundwater in rare earth mines, characterized by high ammonia nitrogen concentration, strong acidity, and high concentration of heavy metal ions, a heterotrophic nitrification-aerobic denitrification (HNAD) high-efficiency denitrification reactor was constructed by using corncob, ceramite and cement as composite fillers. The denitrification performance and mechanism of HNAD in rare earth mine groundwater treatment under the coupling effect of composite fillers were studied. The results demonstrate that the removal rates of NO3--N and NH4+-N can be stabilized at over 94.20% and 81.22% within 23 days, respectively. Furthermore, the reactor can provide an alkaline environment conducive to denitrification. FT-IR and CLSM analyses demonstrate that utilizing corncob as a slow-release carbon source allows the composite filler to offer effective attachment points for microorganisms, facilitating the generation of stable extracellular polymers (EPS) that promote denitrification. The results of microbial diversity analysis indicate that Thauera and Treponema are capable of adapting to the groundwater environment found in rare earth mines, and they represent the primary denitrifying microorganisms present in the reactor. This study offers a theoretical foundation and technical guidance for the application of HNAD in the groundwater of rare earth mines. |
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