Comparison of single-vs dual-chamber microbial electrolysis cells performance for biohydrogen production

Abstract In this study, fed batch single- and dual-chamber microbial electrolysis cells (MECs) were operated to compare differences in the electrohydrogenesis performance at 0.8 V applied voltage and hydraulic retention time (HRT) of 48 h. Results showed that current intensity, current density, COD removal efficiency, and H 2 production rate were higher in the dual-chamber MEC than in the single-chamber configuration. Electromethanogenesis and homoacetogenesis scavenged the H 2 from electrohydrogenesis thus reducing H 2 generation, as demonstrated by cathodic efficiencies less than 10%. It appears that homoacetogenesis overshadowed H 2 production in the dual-chamber MEC, as reflected by a coulombic efficiency greater than 100%, likely induced by a high H 2 partial pressure. These results portray MECs as an energy-efficient scheme for bioH 2 production in addition to removal of pollutants (COD). This study presented valuable information when deciding on suitable reactors and optimizing reactor design.