Rapid screening approach to evaluate MEC performance for biohydrogen production using synthetic and real organic waste-derived substrates

In this study, a rapid screening strategy was developed to accelerate the identification of optimal operating conditions in dual-cathode microbial electrolysis cells (MECs) for hydrogen production from synthetic and real waste-derived substrates. The approach consisted of progressively increasing the hydraulic loading while evaluating system performance through current production, COD removal efficiency, hydrogen recovery, and electrochemical efficiencies, enabling rapid identification of operational boundaries and the onset of the performance plateau, guiding the selection of the most fitting operating regime for subsequent steady-state investigations. The real substrate, obtained from dark fermentation of food waste and sewage sludge, exhibited a high organic acid content (82% OA/CODsol) and a low redox potential (≈ −0.278 V vs SHE), confirming its suitability for bioelectrochemical conversion. The dual-cathode configuration achieved complete cathodic electron recovery into hydrogen (CCE ≈ 100%) demonstrating performance improvements, consistent with those expected from enhanced cathodic architecture. Finally, potentiostatic polarization further characterized the electrochemical response of the bioanode. Combined with the proposed screening methodology, these results provide a practical framework for rapidly assessing MEC performance and selecting promising operating conditions before more detailed long-term investigations and scale-up.