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Groundwater denitrification using electro-assisted autotrophic processes: exploring bacterial community dynamics in a
Javiera Toledo-Alarcón1, Eduardo Ortega-Martinez1, Javier Pavez-Jara2
1Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez, Viña del Mar, Chile.
Frontiers in Bioengineering and Biotechnology
|February 6, 2025
Summary
Bio-electrochemical reactors (BER) effectively remove nitrate from groundwater. Applying 1V achieved complete nitrate removal in 4 days, showcasing an eco-friendly solution for cleaner drinking water.
Area of Science:
- Environmental Science
- Microbiology
- Electrochemistry
Background:
- Nitrate contamination in groundwater is a significant environmental and health concern.
- Bio-electrochemical reactors (BER) offer a sustainable approach for nitrate removal through microbial denitrification.
- Understanding the microbial dynamics and operational parameters is crucial for optimizing BER efficiency.
Purpose of the Study:
- To evaluate the effectiveness of two batch bio-electrochemical reactors (BER) at different voltages (1V and 2V) for nitrate removal from groundwater.
- To analyze the bacterial community shifts during the denitrification process.
- To assess the feasibility of using BER with a simple, membrane-free design for groundwater remediation.
Main Methods:
- Two batch bio-electrochemical reactors (BER) were operated at 1V and 2V, with a control system.
- Anaerobic digestate served as inoculum.
- Monitoring included nitrate, nitrite, sulfate, total ammoniacal nitrogen, and 16S rRNA gene sequencing for bacterial community analysis.
Main Results:
- Both 1V and 2V BER demonstrated effective nitrate removal, outperforming the control.
- Complete nitrate conversion to nitrogen gas (N2) was achieved in 4 days at 1V and 14 days at 2V.
- Bacterial analysis identified electroactive genera like *Desulfosporosinus* and *Leptolinea*, and *Hydrogenophaga* was enhanced at 2V.
- No significant reduction in sulfate or total ammoniacal nitrogen was observed.
Conclusions:
- Bio-electrochemical reactors are effective for autotrophic denitrification in groundwater remediation.
- The 1V configuration showed faster nitrate removal kinetics compared to 2V, likely due to oxygen inhibition at higher voltages.
- The study confirms the potential for scaling up membrane-free BER systems using conventional power sources for groundwater treatment.
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