Operational performance of corncobs/sawdust biofilters coupled to microbial fuel cells treating domestic wastewater

• Published in: The Science of the total environment 2022-02, Vol.809, p.151115-151115, Article 151115
• Main Authors: Karla, Montenegro-Rosero, Alejandra, Villamar-Ayala Cristina, Lenys, Fernández, Patricio, Espinoza-Montero
• Format: Article
• Language: English
• Subjects: Animals; Bioelectric Energy Sources; Canna indica (L.); Corncobs/wood chips; Domestic wastewater; Eisenia foetida Savigny; Graphite; Hybrid biofilters; Oligochaeta; Waste Water; Wood; Zea mays
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2021.151115

Biofilters coupled to microbial fuel cells (MFCs) are the most integral treatment technology that generate water-energy nexus for rural zones sanitation. Moreover, biofilters coupled to MFCs, using organic residues as bed filter have not been studied. Therefore, the aim of this study was comparatively to evaluate biofilters based on corncobs/sawdust coupled to MFCs treating domestic wastewater. Biofilters based on corncobs/sawdust (50%, v/v) as bed filter incorporating microorganisms (BM), earthworms/microorganisms (BEM, Eisenia foetida Savigny), plants/microorganisms (BPM, Canna indica L.), and all organisms (HB) were evaluated. These biofilters were coupled to 2 electrochemical systems based on graphite cathodes with graphite (G)/stainless-steel mesh (M) anodes. Three nominal hydraulic loading rates (0.3, 0.5, and 1 m3 m−2 d−1) evaluating removal of organic matter, nutrients and pathogens were monitored. Voltage within electrochemical systems also were registered. Results demonstrated that biofilters based on corncob/wood chips coupled to MFCs reach mean organic matter removal efficiencies over 80% (COD: 86%, BOD5: 91%). Nevertheless, HBG was the most efficient (up to 6%) biofiltration technology monitored. The biofiltration typologies studied reported removal efficiencies of nutrients (NH3-N, PO43−) and pathogens (fecal coliforms) up to 99%. Specifically, BMG and HBG were the biofiltration typologies that registered the highest energy recovery (up to 104 mV, 29 mW m−2). Within all the biofiltration typologies studied, the hybrid biofiltration coupled to MFCs using graphite (HBG) is the one that offers the best water-energy nexus conditions, thanks to its biological complexity. [Display omitted] •HB is the most efficient biofilter, removing 86% of COD, and recovering 104 mV.•Corn cob/sawdust improve (>82%) the removal of nutrients/pathogens within biofilters.•Temperature and hydraulic rate directly influence on voltage from biofilters-MCFs.