Design and thermodynamic assessment of a sustainable waste to energy system for multiple useful outputs

This study includes the development and thermodynamic performance assessment of a new sustainable multigeneration system, with the Woodward Avenue Wastewater Treatment Plant in Hamilton, Ontario, Canada selected as a potential implementation site. The integrated configuration covers sludge incineration, dark fermentation, hydrochar production (HTC), Organic Rankine Cycle (ORC), Multi-Effect Desalination (MED), and a wind farm subsystem to simultaneously produce hydrogen, hydrochar, freshwater, and electricity from wastewater sludge and renewable energy sources. The proposed system achieved an overall energy efficiency of 48% and an exergy efficiency of 42%, demonstrating strong thermodynamic balance and effective heat recovery. The present system is potentially designed to produce approximately 13,950 kg of hydrogen, 1,490 tonnes of hydrochar, 35,500 m 3 of freshwater, and 160 MWh of electricity annually. The results confirm that the integrated system provides an efficient and sustainable approach for waste-to-energy conversion and resource recovery, enabling simultaneous production of clean energy and valuable by-products. An exergoeconomic analysis further highlights the dominant cost drivers and confirms the economic feasibility of the proposed integrated system. The proposed configuration represents a feasible pathway toward low-carbon, circular, and energy-positive wastewater treatment infrastructure. • An integrated multigeneration system for wastewater sludge valorization is proposed. • Hydrogen, hydrochar, freshwater, and electricity are produced simultaneously. • Overall energy and exergy efficiencies of 48% and 42% are achieved. • Exergoeconomic analysis confirms sludge disposal avoidance as the main economic driver.