Nutrients removal and recovery in bioelectrochemical systems: A review

• Nutrients are key contaminants to be removed in bioelectrochemical systems (BES).
• Nitrogen is removed by biological and bioelectrochemical reactions.
• Nitrogen is recovered through ammonia migration and volatilization.
• Phosphorus is removed and recovered in precipitates due to high electrolyte pH.
• Effective and efficient nutrients removal/recovery will make BES more competitive.

Nutrient removal and recovery has received less attention during the development of bioelectrochemical systems (BES) for energy efficient wastewater treatment, but it is a critical issue for sustainable wastewater treatment. Both nitrogen and phosphorus can be removed and/or recovered in a BES through involving biological processes such as nitrification and bioelectrochemical denitrification, the NH4+/NH3 couple affected by the electrolyte pH, or precipitating phosphorus compounds in the high-pH zone adjacent a cathode electrode. This paper has reviewed the nutrients removal and recovery in various BES including microbial fuel cells and microbial electrolysis cells, discussed the influence factors and potential problems, and identified the key challenges for nitrogen and phosphorus removal/recovery in a BES. It expects to give an informative overview of the current development, and to encourage more thinking and investigation towards further development of efficient processes for nutrient removal and recovery in a BES.

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