From Waste to Value
With the capacity to safely transform human faeces into pathogen-free fertiliser in a short period of time, Peepoo can contribute to enrich depleted soil and quickly improve food security.
Because fertilisers are expensive and scarce in less-developed countries, economic systems may develop around the collection and distribution of used Peepoos. The fertiliser produced by used Peepoos can be utilised by households or schools, or sold profitably to local farmers.
Faeces into Valuable Fertiliser
Peepoo is made of a high-performance degradable bio-plastic which meets EU Standards 13432. This means that the plastic not only disintegrates, but also that the molecules are broken down into carbon dioxide, water and biomass. The bio-plastic is made up of a mixture of aromatic co-polyester and polylactic acid (PLA) with small additives of wax and lime. When properly sanitised, the human faeces and urine are rich in nutrients, which can be used to increase crop yields. Furthermore, if mixed with the soil, faeces increase the organic matter content and improve the water holding capacity.
When all pathogens in Peepoo have been inactivated, two to four weeks after use, the treated faeces will mainly be a nitrogen fertiliser due to the added urea for sanitation. Other nutrients, such as Phosphorus and Potassium, are also available for the plants and thereby improve the soil fertility. Additionally, the organic matter in the faeces will improve the soil’s structure, buffering capacity, and water holding capacity. In the long term, this will improve the potential harvest from gardens and fields where used Peepoos have been buried.
The used Peepoo thus offer a safe and rational nutrient for rural or urban farming, not the least because fertilisers are expensive and scarce in less developed countries. Together with the University of Nairobi in Kenya, Peepoople are currently developing an economic system around the resale of used Peepoos. Consequently, the used Peepoos represent a local resource instead of a contaminant.
There are two types of fertilisers: organic or inorganic. Organic fertilisers are composed of organic matter, while inorganic fertilisers are made of simple inorganic chemicals or minerals. The latter can be naturally occurring compounds such as peat or mineral deposits, or manufactured through natural processes such as composting. Or, they can be made out of chemical processes such as the Haber-Bosch process.
Fertilisers typically provide, in varying proportions, three major plant nutrients: Nitrogen Phosphorus and Potassium – N-P-K. They can also contain trace elements with a role in plant or animal nutrition such as boron, chlorine, manganese, iron, zinc, copper, molybdenum or selenium. Nitrogen is vital for the growing process of most plants.
There is an enormous need for fertilisers in developing countries. Of the roughly 850 million people living in chronic hunger in the world, smallholder farmers constitute half of the population. Food insecurity, especially in Africa, is primarily a result of the lack of adequate food production.
First and foremost in Africa, there is a great need to enrich arable land, because crops are diminishing each year due to losses of plant nutrients from the soil. In Africa, there is no tradition of using fertilisers and this factor, combined with old soil, leaves the ground in many cases, extremely poor in nutrients.
The lack of agricultural production in Africa, which causes undernourishment, has been identified as one of the major reasons for Disability Adjusted Life Years (DALY). Today, mineral fertilisers are imported from the western world and are very expensive. More than half of all those who lack toilets live in rural areas where cultivation possibilities might be great. Cultivation also takes place in cities. For example, Nairobi produces 60% of all cultivated food within the city’s boundaries.
Refugee camps are often established on nutritionally poor areas of land that are difficult to cultivate and where people have difficulty in arranging their own subsistence cultivation and thus become entirely dependent on aid for their upkeep. The addition of fertilisers and organic material is required so that land in these areas might be, to some degree, cultivatable.
In Asia, human excrement has been utilised as fertiliser for thousands of years. For example, there has long been a tradition of locating toilets directly above fish cultivation ponds. Restrictions on the use of excrement have been introduced in recent years but as of yet have had no major impact. As a consequence, contagious diseases take a heavy toll, both through water and food.
Faecal volume depends on diet and increases with the consumption of fibres and vegetables. An average person’s excreted mass is 30 to 60 kilos of faeces per year. Urine volume is dependent on water intake and levels of perspiration due to manual movement and surrounding temperature. 1.5 litres is considered an average quantity per day. Both urine and faeces are rich in nutrients. Furthermore, faeces, if applied to the soil, increase the organic matter content and improve the water-holding capacity. Expected nutrients from one person in Sub-Saharan Africa per year are:
Total mass N=2.8 kg P=0.4 kg K=0.5 kg
Urine N=2.46 P=0.27 K=0.37
Faeces N=0.34 P=0.13 K=0.13
Transformed into artificial fertilisers, this equals 6 kg Urea, 2 kg TPs and 1 kg KCL artificial fertiliser. Usage of one Peepoo per day adds an additional 1.5 kg urea per year.