Low-Cost Urine and Greywater Treatment System

The Design Challenge

My first challenge was designing an efficient and low-cost composting toilet that fits low-income communities in urban and highly populated areas. However, after a great deal of research, my focus changed to treating greywater and urine as my niche as a pose to tackling sewage as a whole.

Summary of Research

In the 21st century, 2.1 billion people lack access to quality sanitation and clean water. The statistics about sewage containment globally and specifically in Kenya are what kick-started this project. Overall, sewage coverage in Kenya, the leading economy in Eastern Africa and home to the United Nations Environmental Program, is only 16%. Many large sewage treatment plants responsible for the sewage of Nairobi have shut down leaving only 33% of fecal matter in Nairobi to be treated safely. 12% of Nairobi’s fecal matter is dumped raw without any treatment into the environment, this matter ends up in the Nairobi river and becomes a hazard for the city. Kenya spends about 27 billion KSH annually due to these poor sanitation problems.

The task now came to pinpointing the problem. While Nairobi is the capital of a leading East-African economy, it is also the home of the largest urban slum in Africa, which sits in the center of the city, bordering the business district. Kibera has an estimated population between 200,000 to one million and has open sewage which flows directly into the Nairobi River. With further research, it was discovered that if the containment problem was mitigated in Kibera it would greatly impact the rest of Nairobi. Around this time in the research project, Netflix released a documentary on entrepreneur and philanthropist Bill Gates. It showed the projects that Gates’ foundation was working on. Bill Gates had chosen to focus on WASH, “Water, sanitation, and hygiene”. He turned his focus specifically to sanitation and hygiene since he felt it is more overlooked than clean water. He now holds huge global fares every year where designers show their prototypes for a most “effective” toilet to solve the world hygiene problem; however, these designs are well over the budget of any small town or village that can not afford to keep its waste contained in the first place. At first, it was very intimidating to see that a billionaire was tackling the same problem as me with little progress but, after finishing the documentary I could take away a lot from his experience.

Результат пошуку зображень за запитом kibera slums
Kibera Slums in Nairobi

At this time I was also introduced to Diego, a WaSH specialist who worked at “Sanivation”, a company that focused on sewage containment in developing countries. The company was building a treatment plant in Naivasha and also had many different projects, including making charcoal out of feces. Diego brainstormed with me and we highlighted two main focuses for me, containment and cost. Diego pointed me in the direction of composting toilets, which are ideal for small scale projects. After brainstorming with teachers at school we decided to go ahead with building a cost-effective toilet that fits the Kenyan setting. I have been taking inspiration from a few existing designs.

SunMar Composting Toilet
Self-Contained Composting Toilet

After researching for a long time I started finding that to make a more efficient and effective composting toilet on a small scale I would need to do some type of Urine Diversion Dry Toilet version. I went to an expert who I was in contact with before and asked him for some resources to help me understand. He shared some papers from the UNHCR and other research papers and I learned that even with a Urine Diversion toilet it will still take roughly 2 years for the compost to be safe to use. I decided this was too long for my type of project so I started thinking about what can be done with the urine instead. I started looking into Evapotranspiration and I found something that I could really build on. I decided to deepen my research about Evapotranspiration and potentially even use it for my final design.

Link to Process Journal & Final Reflection Video

This is the link to the process journal, it shows my journey through the design cycle this year.

Low-Cost Urine and Greywater Treatment System

Link to Process Journal