Assisting cultivation of photosynthetic microorganisms by microbial fuel cells to enhance nutrients recovery from wastewater.
Spirulina was cultivated in cathodic compartments of photo-microbial fuel cells (P-MFC). Anodic compartments were fed with swine-farming wastewater, enriched with sodium acetate (2.34gCODL-1). Photosynthetic oxygen generation rates were sufficient to sustain cathodic oxygen reduction, significantly improving P-MFC electrochemical performances, as compared to water-cathode control experiments. Power densities (0.8-1Wm-2) approached those of air-cathode MFCs, run as control. COD was efficiently removed and only negligible fractions leaked to the cathodic chamber. Spirulina growth rates were comparable to those of control (MFC-free) cultures, while pH was significantly (0.5-1unit) higher in P-MFCs, due to cathodic reactions. Alkaliphilic photosynthetic microorganisms like Spirulina might take advantage of these selective conditions. Electro-migration along with diffusion to the cathodic compartment concurred for the recovery of most nutrients. Only P and Mg were retained in the anodic chamber. A deeper look into electro-osmotic mechanisms should be addressed in future studies.
Department of Agricultural and Environmental Science (DiSAA), Università degli Studi di Milano, via Celoria 2, 20133 Milano, Italy.
Alessandra
A
Colombo
Department of Agricultural and Environmental Science (DiSAA), Università degli Studi di Milano, via Celoria 2, 20133 Milano, Italy.
Stefania
S
Marzorati
Department of Agricultural and Environmental Science (DiSAA), Università degli Studi di Milano, via Celoria 2, 20133 Milano, Italy.
Giorgio
G
Lucchini
RSE - Ricerca sul Sistema Energetico S.p.A., via Rubattino 54, 20134 Milano, Italy.
Pierangela
P
Cristiani
Separation & Conversion Technology, Flemish Institute for Technological Research (VITO), Boeretang 200, 2400 Mol, Belgium.
Deepak
D
Pant
Department of Agricultural and Environmental Science (DiSAA), Università degli Studi di Milano, via Celoria 2, 20133 Milano, Italy. Electronic address: andrea.schievano@unimi.it.
Andrea
A
Schievano
D000818:Animals; D001674:Bioelectric Energy Sources; D004566:Electrodes; D010100:Oxygen; D010788:Photosynthesis; D013552:Swine; D062065:Wastewater
D010100:Oxygen; D062065:Wastewater
Microalgae; Nutrients recovery; Photo-microbial fuel cells; Spirulina; Wastewater