Sodium dodecyl sulfate removal from synthetic greywater using microbial fuel cells

Abstract

The increasing freshwater scarcity imposed by the global climate crisis has positioned greywater (GW) reuse as a viable solution to increase the water budget. Microbial electrochemical technologies are emerging as an alternative to enhance the energy efficiency of GW treatment by reducing aeration costs and facilitating the removal of organic compounds. Nevertheless, the presence of sodium dodecyl sulfate (SDS) in greywater poses an environmental risk that requires effective treatment. This study assesses the removal of SDS from synthetic greywater using microbial fuel cells (MFCs) by evaluating water quality and electrochemical performance and characterizing the microbial community formed. To accomplish this objective, triplicated MFC reactors were operated using synthetic greywater (SGW) and SGW with only SDS as the electron donor (SDS-SGW). MFCs with SGW and SDS-SGW showed no significant differences (p > 0.05) on removal percentages of surfactant (96.2 +/- 1.78 %) and soluble chemical oxygen demand sCOD (80.9 +/- 0.67 %). The coulombic efficiency was low, but the SDS-SGW systems presented a higher coulombic efficiency (similar to 13% vs 1.25%) than SGW. Microbial community analysis revealed enrichment of genera associated with organic matter degradation, such as Tesaracoccus and SAR-86_clade, in MFCs with SDS-SGW. Additionally, genera associated with electrochemically active bacteria, including Comamonas, Azoarcus, and Acidovorax, were observed, indicating the development of an electroactive microbial consortium that facilitates surfactant removal. Thus, this study provides new critical insights into evaluating the effectiveness of MFC systems for treating synthetic greywater and linking SDS degradation to the enriched electroactive microbial community.