Sustainable wastewater-to-hydrogen systems in Canada: A scenario-based decision support analysis

abstract

Canada's commitment to single-family residences, supported by a 2/3 home ownership rate, clashes with the environmental issues caused by residential wastewater, highlighting the need for innovative solutions to align housing expansion with environmental sustainability. The presence of untreated wastewater and emerging contaminants also necessitates substantial investments in innovative treatment approaches, like converting wastewater into hydrogen. Faced with the burgeoning issue of wastewater management from single-family residences in Canada, this study employs the Fuzzy Combined Compromise Solution (CoCoSo) methodology to reconcile residential expansion with sustainable waste management. The approach evaluates three scenarios (private sector management, state governance, and AI monitoring) against expert-defined criteria grouped into twelve indicators across three categories: technical-environmental, economic-operational, and regulatory-social. Results show that the AI monitoring scenario ranked highest overall, with defuzzified scores of 5.91 in the economic-operational category and 6.90 in the regulatory-social category. The private sector management scenario led in the technical-environmental category with a score of 5.89, surpassing AI only when the weight of technical criteria exceeded 0.7. These findings support the adoption of an AI-integrated circular system that leverages smart technologies to balance performance, regulatory compliance, and sustainability in residential wastewater-to-energy conversion. © 2025 Elsevier Ltd