Phosphate recovery as struvite within a single chamber microbial electrolysis cell.
An energy efficient method of concurrent hydrogen gas and struvite (MgNH(4)PO(4)·6H(2)O) production was investigated based on bioelectrochemically driven struvite crystallization at the cathode of a single chamber microbial electrolysis struvite-precipitation cell (MESC). The MESC cathodes were either stainless steel 304 mesh or flat plates. Phosphate removal ranged from 20% to 40%, with higher removals obtained using mesh cathodes than with flat plates. Cathode accumulated crystals were verified as struvite using a scanning electron microscope capable of energy dispersive spectroscopy (SEM-EDS). Crystal accumulation did not affect the rate of hydrogen production in struvite reactors. The rate of struvite crystallization (g/m(2)-h) and hydrogen production (m(3)/m(3)-d) were shown to be dependent on applied voltage and cathode material. Overall energy efficiencies (substrate and electricity) were high (73 ± 4%) and not dependent on applied voltage. These results show that MESCs may be useful both as a method for hydrogen gas and struvite production.
Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, PA 16802, USA.
Roland D
RD
Cusick
Bruce E
BE
Logan
D004566:Electrodes; D004572:Electrolysis; D017616:Magnesium Compounds / Q000302:isolation & purification*; D008855:Microscopy, Electron, Scanning; D010710:Phosphates / Q000302:isolation & purification*; D013052:Spectrometry, X-Ray Emission; D000069877:Struvite
D017616:Magnesium Compounds; D010710:Phosphates; D000069877:Struvite