Enhancing bioelectrochemical hydrogen production from industrial wastewater using Ni-foam cathodes in a microbial electrolysis cell pilot plant

Microbial electrolysis cells (MECs) have garnered significant attention as a promising solution for industrial wastewater treatment, enabling the simultaneous degradation of organic compounds and biohydrogen production. Developing efficient and cost-effective cathodes to drive the hydrogen evolution reaction is central to the success of MECs as a sustainable technology. While numerous lab-scale experiments have been conducted to investigate different cathode materials, the transition to pilot-scale applications remains limited, leaving the actual performance of these scaled-up cathodes largely unknown. In this study, nickel-foam and stainless-steel wool cathodes were employed as catalysts to critically assess hydrogen production in a 150 L MEC pilot plant treating sugar-based industrial wastewater. Continuous hydrogen production was achieved in the reactor for more than 80 days, with a maximum COD removal efficiency of 40 %. Nickel-foam cathodes significantly enhanced hydrogen production and energy efficiency at non-limiting substrate concentration, yielding the maximum hydrogen production ever reported at pilot-scale (19.07 ± 0.46 L H