Dear Tore,

Thanks for your interest. We are well aware of the potential benefits of UDDT, and it is clear that ideally, you would have a two-chamber UDDT with local reuse of endproducts. In that particular case, it was not the option chosen by the local stakeholders, and there is a clear issue of social acceptance in that respect. Using raw urine is not something that everyone is ready to do, and the transport of urine also has a cost, as highlighted in other UDDT case studies such as Durban. In general, I would not count on the sale of urine to support operational costs - it is often rather a cost than a benefit.

More than anything else, this report addresses the questions of financial viability when considering to collect and treat feces centrally. Per se, centralising treatment where there is an interest for reuse at municipal level (for example for a tree nursery) is not a bad idea, and such a concept is also pursued by the "container-based sanitation" stakeholders. However, this, as you rightly mention, has financial implications. These may be partially softened by bundling several municipal services.

Best regards,

Philippe Reymond

Fascinating report.
One of the major benefits of a UDDT is the reuse of the urine and feces.  In this report both there was very little discussion of the benefits.  There appears to be agriculture in the area but there was no effort to sell the urine to the farmers as a fertilizer.  The sale of the urine could have provided funds to help support the operation.  I believe in a 2 chambered UDDT where one chamber is used for 6 months and then the other for six months.  If the unused chamber is allowed to heat and dry the product can be used as a conditioner for the agricultural fields.  Setting up a system where the feces are collected weekly is expensive and the feces are difficult to handle correctly, and having a plant the either sanitizes of destroys the feces is expensive and requires parts/materials that are not indigenous to the area.  ie if a part breaks it is difficult to replace.
It needs to be a closed loop system and that can only be accomplished by using both the urine as a main fertilizer source (sold) and using the dry feces as a soil conditioner.

Dear all,

This post is to share with you the case study of 500 urine-diverting dry toilets (UDDTs) built in 2014 in seven neighbourhoods of the municipality of Arbieto, Valle Alto de Cochabamba, Bolivia, along with a faeces composting plant. The international NGO implementing the programme had to leave the country before the plant and any management scheme could start to operate, leaving thehouseholds alone with a toilet system designed for a regular faeces collection service.

In 2016, Eawag-Sandec, in partnership with Fundación AguaTuya and Helvetas, launched a study aimed to analyse the situation two years after implementation, understand users’ perceptions and compare collection service scenarios. The study investigates how the different personal motives for building a UDDT influenced the sustainability of the toilet, and presents different scenarios for the management of faeces, urine and domestic solid waste. The work provides interesting insights into the challenges faced by municipalities to service a higher number of UDDTs, and the condition of sustainability for such services. The results show how a combined collection of solid waste and collected faeces could help increase the viability of the service in a case where households do not want to use the sanitation products onsite. The attached case study report is available in English and in Spanish. Additionally to the report, we also share the cost calculation model (Excel) for the different service scenarios,which may be a useful tool for a first approximation of service costs in similar contexts.

We hope that this study can help address similar situations and contribute to the reflections of service models for UDDTs.

Best regards,

Philippe Reymond & Eva Reynaert