Phosphorus recovery from artificial wastewater by microbial fuel cell and its effect on power generation

• Artificial wastewater containing phosphorus was treated by single chamber MFCs.
• With NH4 and Mg, struvite precipitated on the cathode, with Mg alone, cattiite.
• As the amounts of NH4 and Mg were increased, the more precipitate was observed.
• Formation of precipitate caused a decrease in performance of the cathode.
• By the removal of precipitate, cathode performance recovered to the initial level.

The effects of ammonium (NH4) and magnesium (Mg) on the precipitation of phosphorus in artificial wastewater by an air–cathode single-chamber microbial fuel cell were investigated. When both NH4 and Mg were added to the wastewater, phosphorus was precipitated as struvite. Almost no precipitation occurred with the addition of only NH4, while phosphorus was precipitated as cattiite with the addition of only Mg. However, the amount of precipitate was less than that observed in experiments in which NH4 was also added. As the amounts of NH4 and Mg were increased, more precipitate was observed. Precipitated phosphorus on the cathode was recovered by dissolution in Milli-Q water and MES buffers. It was discovered that the formation of a precipitate reduced the performance of the cathode. Dissolution treatment caused the performance of the cathodes to increase to their initial level.

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