Assessing wastewater treatment configurations for performance and greenhouse gas emissions: a simulation-based study for a plant in Ecuador
Academic Article in Scopus
Wastewater treatment plants (WWTPs) lie at the water¿climate nexus, emitting greenhouse gases (GHGs)¿particularly methane and nitrous oxide¿often unaccounted for in Global South regulations. Using high-quality influent data (2017¿2020) from an Ecuadorian plant, we simulated four common configurations in STOAT: conventional activated sludge (CAS), anaerobic¿anoxic¿aerobic (A2/O), trickling filter (TF), and sequencing batch reactor (SBR). All met local effluent standards, but their climate footprints differed significantly. The SBR had the lowest emissions (12,160 t CO¿-eq/year)¿28% less than A2/O¿due to superior nitrogen removal that minimized N¿O, despite higher energy demand. A2/O emitted the most (16,961 t CO¿-eq/year), revealing a critical design¿performance gap. In hydroelectric-dominant grids, where indirect CO¿ is low, nitrogen management¿not energy use¿becomes the primary lever for decarbonization. Our results show that regulatory compliance alone does not ensure climate sustainability. We provide a replicable, data-driven framework to guide low-carbon, climate-resilient WWTP planning in data-scarce regions.
