Challenging the reengineered toilet

We are satisfied with the results of the field test, although it was very challenging. The goal of the field test was to validate the totally reengineered working model under real conditions. Therefore, 10 people were asked to use the toilet over a period of one month and the public was invited to use it on public usage days and to provide their feedback as well.
The results of the previous field test in Kampala, Uganda, in 2013 led to a complete reengineering of the Blue Diversion Toilet. The reengineering focused on reducing the toilet size and simplifying the use of the toilet because both attributes were criticized by the users. The latter included replacing the foot pump by electrical pumps which led to a more sophisticated electronics set-up. We knew from the beginning that more electronics would pose a challenge, but we wanted to try it anyway, because electronics are comparatively cheap components for an envisaged large volume production. We were also aware that the toilet base (containers) had not yet reached prototype stage. However, early field testing proved to be very valuable and was a reason for conducting this field test with a toilet that was not yet a full prototype.

Let's have a closer look at the results. The field test in Nairobi was accompanied by a social science study funded by Eawag. Sixty interviews with regular users and 300 interviews with one time users were collected. The evaluation was largely positive and showed that people
- like the look of the toilet (100%)
- think it’s easy to use (95%) and
- would also recommend it to friends and family (94%).
Furthermore, a household survey with 1’400 people was conducted to gather information about the current sanitation situation in two informal settlements of Nairobi (Mukuru and Kibera).

Retrofitting possible in 50% of the toilets

The working model was successfully retrofitted in an existing Sanergy superstructure which was a major goal of the field test. However, moving different features for maintenance and servicing was challenging because of the extremely limited space within the latrine. Observations of 227 toilets during the household survey showed that retrofitting is possible in 50% of the toilets. For the field test the doorframe had to be removed temporary to install the toilet. This minor adaption is necessary for most of the superstructures as only 10% of the doors are large enough to fit the Blue Diversion toilet. Yet 72% of the eligible latrines are built with iron sheets and are therefore easier to adapt than other superstructures. Additionally the roof would also need to be raised in 30% of the toilets with a suitable surface area. These minor adjustments would allow avoiding the construction of an expensive new superstructure (~40% of on-site sanitation costs in East Africa).

Largely positive evaluations

We conclude that in general the field test was satisfying: The 60 interviews with regular users and 300 interviews with one time users provided largely positive evaluations of the Blue Diversion Toilet and we now have a clear picture about what needs to be improved: 

• The hydraulic system needs further simplification and the number of components needs to be reduced
  
• Further development of the electronics and the software to make it more robust and less vulnerable to failures
  
• Further design work should focus on maintenance and servicing aspects. The collaboration with Sanergy gave important insights into the running of a reliable collection system and its challenges.
  
• Adapt the pan for muddy and water logged areas e.g. by expanding the product range with sitting module or an in-between sit-squat module to prevent mud from clogging the mechanism.
  

by Rahel Künzle, Ulrike Messmer and Mark O'Keefe

The toilet was loaded onto a handcart and dragged a mere two kilometres through the winding streets, underneath overhanging power lines and squeezed in between many kiosks. Rahel winced with each bump as she thought of all the potential parts that could be damaged. What would happen to the water filter system and all of the electronics linked that control the functioning of the toilet? After reaching the railway line that divides Mukuru Rueben and Mukuru Kwa Njenga, the transport team decided that it would be best to carry the toilet for the final leg of the journey by hand. These final few metres were only made possible by borrowing some gum boots to enable the team to walk through the muddy street that leads up to the installation site.

The toilet was installed next to the home of Joseph and his family. They have kindly agreed to use the Blue Diversion Toilet for a month and provide feedback on the functioning and features of the toilet. In addition, a series of tests will be conducted that will measure the quality of the recycled water and the power requirements of the toilet. Although the toilet hit some bumps it was installed successfully and is now fully operational. The successful installation means that Rahel went home with a big smile on her face when the toilet door finally swung shut. 

And this is what brings us to work with Sanergy: we both seek to develop aspirational, user-friendly technologies is a shared aim for both EAWAG and Sanergy. The evolution of our Blue Diversion Toilet has focused on developing a product that is not only affordable but comfortable and aspirational.

This is the second version of the Blue Diversion Toilet. The first version, designed and tested in April 2013 in two slums in Kampala with our partners at Makerere University, offered some compelling feedback. After interviewing 1500 households, we learned that the toilet was too high so it would not fit into current latrine structures, the foot pump proved difficult to operate for younger children and old or infirmed adults and  we also were challenged by other technical glitches. These issues were tackled by the engineers at Eawag, the design team and new partners Tribecraft. The new collaboration resulted in a re-designed and re-engineered toilet. It is a smaller, more efficient system that can be retro-fitted into existing latrine structures with minimal cost.

Now, with Sanergy, we would like to find out about different issues related to the operation and functioning of the Blue Diversion Toilet within a different informal settlement. The engineers would like to know how the toilet functions during regular day to day usage. The design team would like to find out how users evaluate the features of the toilet. The business team would like to understand the willingness to pay for the new technology. Finally, the social science team would like to understand why households and local business owners decide to invest in sanitation infrastructure. The toilet has arrived and is currently being installed so we are now ready to test the toilet. Watch this space for updates on our progress over the next 3 months.

All photos taken by Callum Jelley