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The report introduces a technology-neutral sustainability assessment method based on five pillars: social, environmental, economic, health and hygiene, and technical/institutional sustainability. Applying this to Montero, Bolivia, the study compares four systems: conventional gravity-fed sewers (System 1), condominial sewers (System 2), septic tanks with soak pits (System 3), and urine-diverting dry toilets (UDDTs) (System 4). Findings indicate that while conventional systems have high social acceptability, they are the least affordable and most vulnerable to water scarcity and flooding. System 4 (UDDTs) performs best in health, water use, and climate resilience. Optimization—such as adding inlet screens, using personal protection equipment (PPE), and implementing scheduled emptying—generally improves health and environmental outcomes but increases technical complexity and reduces economic sustainability. The report argues for a city-wide inclusive sanitation approach using a mix of these systems to balance trade-offs between cost, health, and environmental protection.

The report evaluates four sanitation configurations in Montero, Bolivia, finding that while the city's utility cooperative COSMOL successfully manages a mix of centralized and decentralized systems, significant gaps in governance, technical optimization, and public awareness persist. It highlights that urine-diverting dry toilets (UDDTs) offer the highest environmental potential and that local farmers are open to using treated sanitation by-products as fertilizers, provided quality and price are managed. However, household adoption of non-sewered systems is hindered by perceptions of odors and a view of such technologies as merely transitional.

The report evaluates four sanitation system configurations in Montero, Bolivia, finding that while the utility COSMOL has successfully implemented mixed services, significant gaps remain in environmental sustainability and governance. It highlights that minor technical optimizations can reduce health and environmental risks across all systems, with urine-diverting dry toilets (UDDTs) offering the highest potential for impact reduction. While local farmers show interest in sanitation-derived fertilizers, household acceptance of on-site systems is hindered by concerns over odors and vectors. The report concludes that upscaling sustainable sanitation requires stronger collaboration between local authorities and COSMOL, new policy instruments, and a long-term strategic vision.