Tubular photo-MFC reactors as wastewater polishing treatment step with simultaneous electricity production

Abstract

Wastewater treatment processes energy and emissions issues led researchers to investigate more sustainable alternative technologies, aimed at achieving effective contaminants removal with simultaneous resources recovery (i.e., energy). The combination of microbial fuel cell (MFC) technology with microalgal-based processes in a photo-MFC (PhMFC) could potentially reduce GHGs impact of wastewater treatment, capturing anodically produced CO2 and photosynthetically convert it into oxygen, with a bioelectrochemical, cathodic polishing step. Two tubular PhMFCs were operated with synthetic wastewater under different conditions. Organic matter and nutrients removals and electricity production were monitored under each tested condition. Energy losses and design issues were also analyzed. The two PhMFCs globally proved to be effective in COD (up to 94%), total nitrogen (55%) and total phosphorus (60%) removal, with simultaneous bioelectricity production (up to 5.5 ‧ 10−4 kWh m−3). The presence of microalgae also opens the possibility of recovery opportunities connected to the post-processing of the cathodic effluent