Sustainable electroless nutrient recovery from natural agro-industrial and livestock farm wastewater effluents with a flow cell reactor

Nutrient removal using renewable/green energy sources and their impact on the surrounding environment is still limited. To fill this knowledge gap, we studied the simultaneous production of struvite, hydrogen, and electricity with no applied voltage/current or chemical adjustment using a flow-cell reactor in farm wastewater compositions, and their impact on the surrounding environment by using life cycle assessment (LCA). In a 3 h experiment, the flow cell reactor removed up to 87 % of phosphate and 77 % of ammonia thus improving water quality. The produced electricity decreased over time due to the formation of a passivating film and hydrogen bubbles on the magnesium anode. Surface characterization techniques (FT-IR, XRD, SEM) indicated that the obtained struvite was of good quality, while chemical analysis showed < 2.6 % of Ca²⁺as co-precipitate. The LCA showed that generation of struvite, hydrogen, and electricity provided major environmental credits, but the manufacturing of magnesium anode had environmental burdens.