In our project, the name of the game is EcoSan, which of course is apparent throughout this blog. But what does EcoSan, or ecological sanitation, to be more exact, actually mean?
The ecological sanitation approach perceives human waste as a resource that can be utilized safely in agriculture. The aim of the EcoSan approach is to close the loop between waste production and agriculture in a sustainable way while protecting the environment. This can be conducted with a variety of methods and toilet types. When managed appropriately, the nutrient-rich urine, as well as composted faeces we all produce, can be used as efficient low-cost fertilizers. This is also a way to help tackle the current scarceness of phosphorus and potassium, which are relatively abundant in urine, in addition to nitrogen and micronutrients. During our field trip to Dar es Salaam, we saw some amazing plant-growth results that local farmers had produced with urine alone.
Ecological Sanitation is nothing new – using human waste as fertilizer has been a popular practice for example among the Chinese for over 2,500 years (Lüthi et al., 2011), and compost from outhouses in Finnish summer cottages has also been utilized in gardens for hundreds of years. Today, however, what is widely considered the most modern approach is collecting and treating human waste via sewerage networks. In an article published by the Conversation (2017), Tamara Avellán states that “today the flush toilet probably stands as one of the most unsustainable innovations in human history”. This is because the most common type of centralized systems needs vast infrastructure, huge resources to treat the waste in treatment plants, and of course an immense amount of water that greatly increases the volume of waste that needs to be treated.
The EcoSan dry toilets that have been built within this project are urine-diverting dry toilets (UDDT) that separate urine and faeces into their own containers. The faeces are composted with sawdust, and the urine is stored for six months in order to eradicate pathogens from respective containers. This means that the excreta can be securely treated on the spot to the point that safe reuse of the nutrients in the waste is possible, instead of having to build large scale sewage and treatment infrastructure. This is ideal in a place like Dar es Salaam where the sewage network only covers a small fraction of the population – approximately 10 %. Another bonus of the UDDT toilets is the fact that the dry toilet process requires close to no water. Furthermore, the raised toilets with waste containers suit the conditions of the city very well because of the extremely high water table. The majority of toilets in Dar are pit latrines – most of which are basically pits in the ground – that contribute to the spread of pathogens to the environment especially during the rainy season when rainwater flushes human waste out to the streets.
Currently, 70 % of the population in Dar live in informal settlements without proper sanitation – and to make matters worse, the population of the city is about to double by 2030 (Jaeger & Spiegel, 2017). That being the case, there is a pressing need to deal with the sanitation issue as soon as possible. Because of the reasons described in this text, EcoSan toilets could be part of the solution in offering sustainable solutions to sanitation, the lack of which has been described as the most severe problem in urban settings in the Global South.