Project Results: 

eSOS: efficient and intelligent toilets

Using state-of-the-art technology for public toilets

This pilot tested the prototype of a toilet with smart functions in informal settlements in Nairobi. It supported developer IHE Delft in its design process. The toilet is hygienic, safe and affordable and is separating urine from faeces. It also collects data to support its operation and for the management of waste. The innovation is part of the eSOS: emergency Sanitation Operation System, which makes maximum use of state-of-the-art ICT and technology for faecal and septic sludge treatment. It integrates monitoring, operation and maintenance of sanitation system components.

Key results

  • Making and testing of an advanced prototype of the toilet, including the molds and electronics.

  • The prototypes were successfully tested by Sanergy in Nairobi for ‘slum conditions’: an important step closer to a final, commercial viable project.

  • Improvement of design, including appropriate modular container system for poo, urine and grey water. Some design adaptations are to be made.

  • The solid faecal sludge is usable for reuse (e.g. Sanergy is making compost).

Tips for the future

  • Prototype development takes up quite some time, partly due to the iterative nature of this process: continuous improvements and new ideas.

  • Give enough attention to the logistical part in transport and import, as this is easily underestimated.

  • Reserve enough time for scientifically sound on -the-ground- performance research.

Potential for growth
These eSOS toilets could very well be used for shared facilities in refugee camps and slum areas. There is a lot of interest from big players, such as Red Cross and UNICEF to apply the toilet in refugee camps. Local production and/or assembly is a must to get the price affordable (less than € 800 per unit).

Project partners
IHE Delft, Sanergy, Flex design,

March 2017- June 2019


Nairobi, Kenya


The eSOS concept was developed in 2014 (Brdjanovic et al., 2015). eSOS Smart Toilet is in the hearth of the system. Thanks to funds provided by the Bill & Melinda Gates Foundation and Asian Development Bank, the experimental version of the toilet was manufactured and tested in a temporary human settlement in by hurricane destroyed Tacloban City in the Philippines (Zakaria et al., 2015, 2016, 2017). Based on successful testing, the consortium was encouraged to proceed with the developments. In the meantime the toilet was awarded with several international prizes. With funds of Via Water, we are currently developing a fully functional prototype to be tested in the field in Nairobi as part of the sanitation system of Sanergy.

Brdjanovic D., Zakaria F., Mawioo P.M., Garcia H.A., Hooijmans C.M., Pean T.Y., Setiadi T., (2015) eSOS® - emergency Sanitation Operation System. Journal of Water, Sanitation and Hygiene for Development, 5(1):156-164.
Zakaria, F., Harelimana, B., Ćurko, J., van de Vossenberg, J., Garcia, H.A., Hooijmans, C.M., Brdjanovic, D. (2016) Effectiveness of UV-C light irradiation on disinfection of an eSOS® smart toilet evaluated in a temporary settlement in the Philippines, International Journal of Environmental Health Research, 26(5-6):536-553.
Zakaria F., Hooijmans C.M., Garcia H. and Brdjanovic D. (2015) Decision support system for the provision of emergency sanitation. Science of the Total Environment, 512–513:645–658.
Zakaria F., Thye Y.P. Hooijmans C.M., Garcia H.A., Spiegel A.D. and Brdjanovic D. (2017) User acceptance of the eSOS Smart Toilet in a temporary settlement in the Philippines, Water Practice & Technology , 12(4).

Project Plan

Project implementation plan includes:
1. Prototype design and detailed design documentation including a mock-up in scale 1: 5 and 3D visuals
2. Manufacturing the electronics of the toilet including adjustment of the existing software
3. Manufacturing and purchasing integral structural parts of the toilet prototype
4. Manufacturing, assembling electronic and structural parts, testing and commissioning of the prototype
5. Shipping, transporting, erecting, securing the prototype at field location in Nairobi + other local logistical arrangements
7. Cleaning, deploying and shipping one toilet back to Netherlands
8. Optional testing at the location of Red Cross in NL
9. Exposit at final location (Green Village of TU Delft or garden IHE Delft)
10. Dissemination and communication of project results + reporting

Target group

Target group are inhabitants of the peri-urban location in Nairobi. The exact location is not determined yet.


Learning agenda is about what we learn from outcomes and results of development and field testing of the eSOS Nairobi Pilots. It makes extensive use of experiences from the previous field testing in Tacloban (which is well-documented in scientific publications and technical reports) and lessons learned from other’s similar actions in the past. The main topics of research are: 1) testing functionalities of the toilets and associated software and communication system, 2) evaluation of structural strength hand resilience to use and theft, 3) operational, maintenance and managerial aspects, and 4) social acceptance and gender issues. All relevant project outcomes and results including lessons learned will be documented and shared as agreed.

1. Testing functionalities of the toilets and associated software and communication system
The following functionalities of the will be tested and evaluated in Delft and Nairobi:
• Functioning and efficiency of odour management system which includes odour stop components of the urine, faeces and grey water collection tanks, odour stop activation/deactivation system in the above-structure, odour evacuation system (ventilation) in both under- and above-structure, and odour treatment;
• Usefulness and functioning of an interchangeable toilet seating/squatting arrangement;
• Functioning of separation devices between urine, faeces and grey water;
• Functioning of solar power panel;
• Functioning and usefulness of rain water harvesting roof arrangement;
• Function of GSM and GPS positioning and communication components;
• Functioning of sensors for occupancy, volume of urine and faeces and grey water collected, and , volume of service water;
• Working of exterior and interior lights and illumination;
• Functioning of UV disinfection lights;
• Role of nano-coating;
• Functioning and usefulness of smart card entry system;
• Functioning and necessity of SOS panic button;
• Functioning of the water usage control elements;
• Functioning of the operation and monitoring software.
2. Evaluation of structural strength and resilience against usage and theft.
Valuable information will be obtained concerning:
• Materials choice and durability against sunlight, dust, wind and moisture/rain;
• Waterproofness and detection of leaks;
• Structural strengths of components and the toilet as whole;
• Resistance to theft;
• Issues related to transport and storage;
• Stability of structure with full and empty tanks and combinations in between;
• Structural strength of electronic components;
• Stability of server and communication components.

3. O&M and managerial aspects
• Experience with employment/deployment in the field;
• Characterization of faeces, urine, grey water and service water (quantitative and qualitative);
• Visitor analysis (number, day-night, male-female, child-adult)
• Handling collection tanks (easiness to empty/replace tanks, weight, ergonomics, health and safety);
• Filling time / emptying frequency;
• Dependence on solar energy, length of battery life;
• Availability of GSM coverage and options;
• Issues with GPS signal and connectivity;
• Issues with data transfer, storage, accessibility and cyber security;
• Communication with server and software;
• Protection of data and privacy;
• Filling rate of service water and source(s);
• Vector attraction (day and night);
• Algae formation in service and grey water tanks and mitigation measures;
• Cleaning practices (frequency, efficiency/cleanness, agents and means, coverage;
• Guarding / attendance;
• Security issues;
• Hand washing practices;
• Role of location and usage;
• Frequency and reasons of using the SOS panic button;
• Responsiveness of the operator/service;
• Arrangements (two pilots in parallel) regarding separate male and female use vs combined use.

4. Social acceptance and gender
• Privacy;
• Gender;
• Less able users;
• Perception of toilet design;
• Like and dislike features and functionalities;
• Cultural issues (squatting vs seating, wipers vs washers, menstrual hygiene)
• Characterization/statistic of users groups;
• Type of location vs type of users;
• Type of users vs character of the toilet (public vs household);
• Frequency and reason to use;
• Role of education vs usage of toilets;
• Safety and dignity (intruders, being self-locked, harassment inside and in vicinity);

Overview of Goals

The new eSOS Nairobi Pilot project includes (i) development, manufacturing, assembling and testing of the full-size prototype (3 units) in the Netherlands, (ii) shipping, installation and testing in real life conditions in Nairobi, and (iii) evaluation, feedback, outlook, sharing and dissemination of results and experiences. Implementing consortium consists of IHE Delft, FLEX / design B.V.,, and Sanergy. Arrangements between IHE Delft and individual consortium partners are already in place. The project is on schedule and the design phase is completed. In the coming months manufacturing of the toilet will take place.

Results and indicators

  • eSOS prototype design completed
  • eSOS Monitor developed