The Potential of Non-sewered Sanitation (NSS) in Urban Settings: Exploring Core Value Propositions across Global and Local Contexts

Non-sewered sanitation (NSS) systems, such as Multi-Unit Reinvented Toilets (MURTs) and Omni-Processors (OPs), have emerged as viable on-site systems capable of providing safe sanitation with treatment and resource recovery capabilities. In this analysis, the opportunity space of NSS systems as alternatives to the centralized sewer collection and treatment was evaluated by cost per user per day (USD·capita-1·day-1) calculated from capital and operational costs of centralized and NSS systems as the performance indicator. The results were discussed in the context of three NSS core value propositions: (i) expanding coverage, (ii) distributing treatment, and (iii) enhancing resilience. The results showed that NSS implementation can often outperform centralized systems across facilities in the US and global cities in terms of cost per user per day when considering country, city, or facility-specific contextual features for analysis and characterization. Case studies on previous implementation highlighted the importance of context-specific NSS deployment to address climate change and city dynamics. The results from this work can contribute towards effective planning and decision-making to ensure globally sustainable sanitation coverage.