Development and analysis of an integrated renewable wastewater to energy system for hydrogen production

Wastewater treatment plants can be transformed from energy-intensive facilities into resource recovery systems through integrated waste-to-energy configurations. In this study, a conceptual hybrid renewable energy model is developed for municipal wastewater treatment plants using the Duffin Creek facility in Ontario, Canada, used as a specific case study for a potential application. The proposed system simultaneously generates electricity, hydrogen, and useful heat from sludge-derived biogas, wastewater streams, and solar energy. Anaerobic digestion supplies biogas to a combined gas and steam power cycle, while an integrated bioelectrochemical reactor including microbial fuel cell, microbial electrolysis, and photoelectrochemical units enables hydrogen and supplementary electricity production. The system delivers a net electrical output of 6.32 MW and 2.43 MW of useful heat, while the integrated reactor produces 63.69 kg/day of hydrogen and 26.99 kW of electricity. The overall energy and exergy efficiencies are calculated as 44.48% and 33.74%, respectively. The results show that integrating thermochemical and bioelectrochemical pathways can improve energy recovery and support hydrogen production in municipal wastewater treatment plants.