Combining sewered and non-sewered sanitation in Montero, Bolivia

This report evaluates the integration of sewered and non-sewered sanitation systems in Montero, Bolivia, focusing on sustainability, user preferences, agricultural reuse of waste, and governance capacity. It highlights the role of the cooperative utility COSMOL in managing mixed systems and identifies technical and policy gaps that hinder the scaling of sustainable on-site sanitation.

• The city of Montero utilizes a mixed sanitation approach managed by the cooperative utility COSMOL, where 36% of the population is connected to a centralized sewer system with waste stabilization ponds, while approximately 1% use urine-diverting dry toilets (UDDTs) and nearly two-thirds use septic tanks or other on-site systems.
• A sustainability assessment of four technical configurations (conventional sewerage, condominial sewerage, septic tanks, and UDDTs) found that all existing setups face significant challenges, particularly regarding environmental sustainability due to the discharge of nutrients and organic matter. However, minor optimizations—such as adding inlet screens, improving sludge treatment, and disconnecting roof drainage—could improve sustainability without requiring major additional investments.
• Urine-diverting dry toilets (UDDTs) offer the highest potential for reducing environmental impact if optimized for the collection and treatment of both urine and faeces for reuse. Despite this, they have the lowest implementation rates and are often perceived by users as only transitory solutions until a sewerage-based system can be acquired.
• Household acceptance of sanitation technologies is primarily driven by cost, the absence of odours and vectors (mosquitos and rodents), and ease of maintenance. While users of on-site systems value low water consumption and reduced environmental impact, the presence of odours and mosquitos remains a major deterrent.
• There is significant demand among local farmers for fertilizers derived from sanitation waste, with the highest interest in treated sludge from wastewater treatment plants (WWTP) and treated wastewater for irrigation. Farmers generally expressed low concern regarding the health or environmental impacts of using these by-products, though the report notes a need for awareness regarding pathogens and contaminants.
• Montero possesses a moderate governance capacity to upscale on-site sanitation. Key enablers include a sense of urgency and willingness to collaborate among COSMOL and non-profit organizations (such as Aguatuya and UNICEF Bolivia). However, significant barriers exist, including a lack of policy instruments, a prevalence of short-term vision in decision-making, and a lack of legal recognition of on-site sanitation as equal to sewer systems for public investment purposes.

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} }