A novel pico-hydro power (PHP)-Microbial electrolysis cell (MEC) coupled system for sustainable hydrogen production during palm oil mill effluent (POME) wastewater treatment

Abstract

Due to accelerating global efforts toward decarbonization, a clean hydrogen (H2) producing technology, Microbial Electrolysis Cell (MEC), has garnered considerable attention. However, MEC's external energy requirement has raised concerns about its sustainability, scalability and application costs. The objective of this research was to build a renewable energy generating system for MECs' performance enhancement during the treatment of Palm oil mill effluent (POME). A novel integration of a pico-hydro-power generator (PHP) with single-chambered MECs exceptionally improved its performance. The performance boost was observed as 1.16 m3-H2/m3d H2 and 113 A/m3current production in concomitant with 73% organics removal from Palm Oil Mill Effluent (POME) wastewater, which is higher than the previous single-chambered MECs studies. 78% H2 recovery rcat (H2) along with 57% coulombic efficiency (CE) corroborated the removal of a high percentage of electrons from POME organic materials to generate >96% pure H2. The MEC nourished POME wastewater degrading communities while stimulating growth of electroactive Geobacter in the anodic biofilm which produced H2. The overall H2 recovery, COD removal rate and energy efficiency of PHP-MEC are superior than other MECs powered by other external renewable energy sources reported to date. The PHP-MEC prototype paves the path of scale up studies to build a renewable energy dependent future.