Defining economic and environmental typologies across 77 countries to prioritize opportunities for non-sewered sanitation

Lack of access to sanitation is a challenge that persists globally, with low sewerage connection rates in many low and lower-middle income countries. Engineered non-sewered sanitation (NSS) technologies can meet treatment requirements without sewers, but their relative sustainability varies across potential deployment sites. Here, we characterize the costs and carbon intensity (CI) of three emerging NSS technologies – two community reinvented toilets and one Omni Processor – across 77 countries, identify sustainability performance typologies, and map typology prevalence in countries across the globe. Locality-specific factors such as wages, diet, and material costs drive regional variability in NSS costs by up to 15-fold and CI up to 2-fold. Low-cost, low-CI typologies are predominantly in countries with lower human development indices (HDI 2-4), demonstrating alignment between sanitation need and NSS opportunity space. By elucidating key sustainability drivers and defining typologies, this work can support early-stage decision-making for NSS technology research, development, and deployment.