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Electrochemically and Bioelectrochemically Induced Ammonium Recovery
Published on: January 22, 2015
Autotrophic denitrification in microbial fuel cells treating low ionic strength waters
Sebastià Puig1, Marta Coma, Joachim Desloover
1Laboratory of Chemical and Environmental Engineering (LEQUiA), Institute of the Environment, University of Girona, Campus Montilivi s/n, Facultat de Ciències, E-17071 Girona, Spain. sebastia@lequia.udg.cat
Environmental Science & Technology
|January 20, 2012
Summary
Microbial fuel cells (MFCs) show potential for removing nitrates from low-conductivity water. However, low ionic strength limits efficiency and leads to nitrous oxide production, with cathodic overpotential causing significant energy loss.
Area of Science:
- Environmental Science
- Water Treatment Technology
- Microbiology
Background:
- Elevated nitrate levels in drinking water pose a global health risk.
- Microbial fuel cells (MFCs) offer a potential solution for water denitrification.
- The application of MFCs in low ionic strength waters (<1600 μS·cm(-1)) remains largely unexplored.
Purpose of the Study:
- To assess the feasibility of using MFCs for denitrification in low ionic strength water.
- To identify and quantify energy losses associated with MFC denitrification.
- To understand the factors influencing nitrogen removal efficiency and energy production.
Main Methods:
- Autotrophic denitrification using MFCs.
- Evaluation of water conductivity impact on nitrogen removal.
- Analysis of energy losses, particularly cathodic overpotential.
- Quantification of nitrous oxide (N(2)O) production.
Main Results:
- Low water conductivity (<1600 μS·cm(-1)) significantly limited nitrogen removal efficiency and power output.
- Incomplete nitrate reduction resulted in nitrous oxide (N(2)O) production (4-20% of removed nitrogen).
- Cathodic overpotential accounted for the majority of energy losses (83-90%), influenced by denitrification intermediates and microbial metabolic activity.
Conclusions:
- MFC technology is feasible for denitrification but performance is constrained by low water conductivity.
- Nitrous oxide emission is a concern in MFCs treating low ionic strength water.
- Addressing cathodic overpotential is crucial for improving MFC efficiency and energy recovery in such applications.
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