Combining sewered and non-sewered sanitation in Montero, Bolivia

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.

• A sustainability assessment of four sanitation system configurations in Montero revealed that all existing setups face significant challenges. Systems involving condominial sewerage, household septic tanks, and UDDTs primarily struggle with environmental sustainability due to high nutrient and organic matter discharge, while centralized sewerage faces issues with household affordability, technical adaptability, and economic sustainability.
• Minor technical optimizations can improve the sustainability of all four examined systems, particularly regarding health and environment, without requiring major additional investments. Optimized systems show lower risks to health and hygiene and reduced contaminated discharges, although they increase technical and managerial complexity.
• Urine-diverting dry toilets (UDDTs) have the highest potential to reduce environmental impacts if optimized and if both urine and faeces are collected and treated for reuse. However, they currently have the lowest implementation rates and are often perceived by users as only transitory solutions.
• Household acceptance of on-site sanitation is primarily determined by cost, ease of maintenance, and the absence of odors, mosquitoes, and rodents. While users appreciate the low water consumption and reduced environmental impact of these systems, the presence of vectors and odors often leads them to prefer sewerage-based technologies.
• There is a promising demand among farmers in Montero for fertilizers derived from sanitation waste, with the highest interest in treated sludge from wastewater treatment plants and treated wastewater for irrigation. Farmers generally expressed low concern regarding the health, environmental, or market impacts of using these products, though there is a noted need for awareness regarding pathogens and contaminants.
• Montero possesses a moderate governance capacity for upscaling on-site sanitation. Key enablers include a sense of urgency and willingness to collaborate among the utility COSMOL and non-profit organizations. However, significant barriers include a lack of policy instruments, insufficient monitoring and evaluation, and a prevailing short-term vision in local decision-making processes.

APA

Liera, C., García, M., Andersson, K., & Kvarnström, E. (2022). Combining sewered and non-sewered sanitation in Montero, Bolivia. Stockholm Environment Institute. https://www.sei.org/wp-content/uploads/2022/02/monterosewageseireport032022.pdf

Chicago

Liera, Carla, Mónica García, Kim Andersson, and Elisabeth Kvarnström. Combining sewered and non-sewered sanitation in Montero, Bolivia. Stockholm Environment Institute, 2022. https://www.sei.org/wp-content/uploads/2022/02/monterosewageseireport032022.pdf.

Wikipedia

{{cite report |last1=Liera |first1=Carla |last2=García |first2=Mónica |last3=Andersson |first3=Kim |last4=Kvarnström |first4=Elisabeth |title=Combining sewered and non-sewered sanitation in Montero, Bolivia |publisher=Stockholm Environment Institute |date=March 2022 |url=https://www.sei.org/wp-content/uploads/2022/02/monterosewageseireport032022.pdf |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{liera2022combining, author = {Liera, Carla and García, Mónica and Andersson, Kim and Kvarnström, Elisabeth}, title = {{Combining sewered and non-sewered sanitation in Montero, Bolivia}}, institution = {Stockholm Environment Institute}, year = {2022}, month = mar, url = {https://www.sei.org/wp-content/uploads/2022/02/monterosewageseireport032022.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }