ECOLOGICAL SANITATION SYSTEM USING HUMAN URINE AS A FERTILIZER TO REPLENISH NUTRIENT-DEPLETED AGRICULTUREAL SOIL  REMIX 

Ecological sanitation system using human urine as a fertilizer to replenish nutrient-depleted agricultural soil

This proposal involves an ecological sanitation system which uses urine as fertilizer and dried fecal matter as a fuel source, and proposes the design of a simple urine-separation toilet system that can be made by women for their households at minimal cost using recycled plastic containers. 

In addition to soil replenishment this proposal also addresses the need for low-cost safe sanitation, and the protection of water supplies.  Implementation of an eco sanitation system has the potential to improve health, nutrition, social and economic conditions, especially for women in impoverished communities. 

Ecological Sanitation is based on the philosophy that wastewater is seen as a source for nutrients for agriculture or as an energy source using the high organic content in excreta.  Humanure, the term for using this waste has been studied for its nutrient potential for soil remediation and for safety of use.  The research has shown that humanure, both urine and feces contain significant amounts of nitrogen, potassium and phosphorous in a form that plants can absorb easily, and are a viable alternative to commercial fertilizers.  In developing countries with highly pathogenic populations, composting of feces requires skill, has severe health implications if done incorrectly and requires several years to see results, whereas urine is safer, requires little skill and produces almost immediate results.   There are a number of designs for urine separation toilets/dry toilets that direct the urine and feces into separate holding tanks.   The current designs require the construction of an elevated platform to accommodate tanks below the toilets for varying commercial pedestal and squat pan toilets accommodating a sitting or squat position only.  Complete separation of fecal matter and urine is safer, more efficient, and a more pleasant experience especially in public toilet situations, due to the higher ratio of urine deposits to feces deposits per person per day.  Separation also avoids possible contamination of the urine by fecal matter, a reduction of flies, and reduction of odors. 

In my opinion the deterrents to the adoption of Eco Sanitation systems is cost, skill and time required to construct the systems.  Designs are needed that require little skill, are inexpensive or free to build, and can be constructed quickly.  As an architect/ designer with a sculpture background  and training in green building, regenerative design and permaculture, I think my love for problem-solving and low tech solutions gives me the skills to tackle the design problem.  I have done some preliminary experiments using recycled containers (video and photographs can be viewed at http://www.greendesignstrategies.com/id91.html ) and am currently researching and testing design ideas in rural Mexico.  My plan for implementation is to continue research in Africa as to design possibilities using locally available materials, to research social customs related to sanitation and the use of urine as fertilizer and feces as a fuel source, and to begin working on implementation strategies based on that research.   I have the unique opportunity of meeting with farmers across African and to visit farms in Malawi, Zimbabwe and South Africa as a participant of the Permaculture Convergence, a bi-annual meeting of Permaculture experts from around the world.  The event will be held in November 2009 in Malawi, and I am looking forward to attending a hosted three week tour of farms in Malawi, Zimbabwe and South Africa.  The Convergence is an excellent opportunity to disseminate information on Eco Sanitation systems through a panel presentation, and I hoping to have the resources to arrive early to construct a prototype toilet diversion system on the site to promote participation and dissemination of the concepts and to explore the cultural issues for different areas of Africa.   

 Needs Assessment-

The majority of people in sub-Saharan African are depend on agriculture for their livelihoods. Africa cannot produce enough food to keep pace with its needs, and per capita food production is declining. Low soil fertility, including depleted nutrients, organic matter and poor water holding capacity are the major factors responsible for depressed yields on small-scale farms across Africa.

Severe soil depletion results in a vicious cycle of declining yields, deepening poverty, and increased degradation of the natural resource base that farmers depend upon.  Subsistence farmers have little access to fertilizers, as soils decline and farm yields drop, impoverished farmers move on to clear forests and savannah, where the cycle begins again.

Fertilizers enhance crop growth and increases nutrition for those who depend on subsistence farming.  Access to fertilizers which are free, plentiful, locally available, and easily applied are needed to create healthy, fertile soils that retain nutrients, water, essential microbes and other soil organisms that promote plant growth and are vital for sustained agricultural development.  Farmers reliant on external inputs are in need of a commercial fertilizer replacement as oil prices escalate the price of oil-based fertilizers rise.  A more sustainable source of fertilizer is necessary as peak oil forces an end to the affordability of these commercial fertilizers. The salts in chemical fertilizers have added to the depletion of natural micro flora, and have increased water use.

 Sanitation- Sanitation can improve social and economic conditions especially for impoverished communities. In sub-Saharan Africa, a baby's chance of dying from diarrhea is almost 520 times that of a baby born in Europe or the United States. Poor sanitation and hygiene and unsafe water claim the lives of an estimated over 1.5 million children under the age of five every year.  World Health Organization statistics indicating that in 38 of the 46 African countries more children under the age of five die from diarrhea than HIV/AIDS.  Other indicators of health risks associated with poor sanitation are the frequency of related parasites that have human fecal origin - about 1 billion people are infected with roundworm and 700 million with hookworm.  Conventional pit latrines contribute to groundwater pollution and can be health and environmental hazards and face a variety of problems like pit collapsing and flooding. Also the need for digging of new pits once the old one is filled is considered a drawback of this conventional technique.

 Urine as a fertilizer- Urine is a locally produced resource that is free.  As a fertilizer it is effective, is a high quality fertilizer, urine is sterile and requires no processing other than dilution, is readily available, can be used immediately or stored, rapid acting, and is easily applied. Urine provides a constant supply of fertilizer, instead of the annual or semi-annual composting systems that require physical labor to aerate and require management.

As a fertilizer, urine is rich in nitrogen and also contains substantial amounts of phosphorus and potassium.   A family of four produces enough urine to fertilize 1/3 of an acre at a rate compared to the application of 100kg per hectare in developed countries -note that Africa currently has the lowest fertilizer use in the world at 8.5kg per hectare.  The use of urine as fertilizer has been studied by Arba Minch University  in Ethopia and the Sodo Agricultural Department investigated the use of human urine as fertilizer for different crops. Their research indicates equal or higher yields of maize and wheat when fertilized with urine when compared with the applications of chemical fertilizer.

The use of dried feces as a fuel source

Due to the difficulty in safely using fecal matter as a soil additive,  I propose the use of dried feces as a fuel source. When using humanure is from a highly pathogenic population a thermophilic composting technique must be used where the temperature rise in the compost is sufficient to kill pathogens and feces, and then aged for one to two years to ensure pathogens have been eliminated. This process requires skill and managemet over time.  Desiccation happens naturally in hot dry climates if the feces are first covered with wood ash after deposit, and then exposed to the air and sun. Addition of ash facilitates pathogen inactivation and decrease the risk for disease transmission during handling and reuse of the material. Desiccation of the material and low moisture contents aid to pathogen inactivation. Esrey et al. (1998) suggested that there is rapid pathogen destruction at moisture levels below 25%, and that this level should be aimed for in ecological sanitation toilets that are based on dehydration. Low moisture content is also beneficial in order to reduce smell and fly breeding.  The ash created by the burning of feces provides a fertilizer with phosphorous and potassium. 

 Advantages of dry toilet systems  

In a dry/urine diversion toilet system, urine is separated from feces which reduces the amount of fecal material to be handled and lowers the risk for disease transmission and reduces odors and flies.  Fecal matter is collected separately in an above-ground closed compartment that prevents leakage into the groundwater and the surrounding environment.

Questions and Answers that provide additional information

Abena Asare

Cannot wait to see the pictures!
This is a fascinating idea and proposal.
Have you done any research about the social acceptability/feasibility of urine as a fertilizer in different locales? where would you begin with dissemination, education, and training after designing the dry toilet? 

GailSwithenbank

Hi Abena,
Thank you so much for your comments.

I have posted a youtube video of the design at-   www.youtube.com/watch?v=LSXvY_NWvso

Research by Arba Minch University in Ethopia with farmers in the Sodo Agricultural Department indicated that the farmers had no issues with adoption of using urine as a fertilizer once they saw the benefits in terms of yield. I do need to do some research on the cultural acceptability or possible taboos of using urine, and of collection methods in different areas. I plan to be in Malawi, Zimbabwe and South Africa for a tour of local farms and education programs in November as part of the Permaculture Convergence in Malawi, this will be an excellent time to do this kind of research as well as an opportunity to look at availability of recycled materials. I am hoping to do some experimentation and training as we travel to develop the process as well as to research some other ideas.

 AlanRye

This idea has merit. The use of urine as a fertiliser requires some understanding. It's low in phosphorus, and urea (the main source of nitrogen) rapidly degrades to ammonia unless it is stabilised by refrigeration or other means. Ammonia can be an effective fertiliser, but it is alkaline and volatile. If the urine is used soon after collection, there are probably few issues. Monitoring of soil nutrients and pH would be helpful.

Hi Alan,
According to Dr. Peter Morgan- "Urine contains a lot of nitrogen and also phosphorus and potassium in smaller quantities, nutrients which are very valuable to plant growth. The nitrogen found in abundance in urine is good for plant growth because it helps to build protoplasm, protein and other components of plant growth. It certainly promotes leafy growth. Leaves become more numerous, go greener and larger and more fleshy with urine application. Phosphorus is important in the root formation, ripening of fruits and germination of seeds, although the percentage of phosphorus compared to nitrogen in urine is low. Potassium is also essential for promoting good fruit (and flower) development. Plants differ in their requirements, but overall plants fed with some urine grow better than plants which never come into contact with urine. Urine is particularly valuable for grasses like maize and leafy green vegetables, and onions, which respond to the high nitrogen content of urine.
When applied to the soil the urea (a small organic molecule) in urine changes into ammonia ions which can be transformed into ammonia gas, which can evaporate and be lost or, in the soil, can be converted by autotrophic bacteria (Nitrosomonas) into nitrite ions and then Nitrobacter into nitrate ions which can be taken up by the plant. The conversion is thus dependent on these bacteria being in the soil. The process takes place in less than two weeks and often within a few days. It is the nitrogen in the nitrate and the ammonia ions which are available to plants, thus the urea in urine must be transformed before it becomes useful as a "plant food." The nitrite ions, present during the conversion, can be toxic to plants, but the period is brief and normally there is little effect on plant growth.
According to Wolgast (1993) one litre of urine contains 11gms nitrogen, 0.8 gms. phosphorus and 2 gms. potassium. That is a ratio of NPK of about 11:1:2. If 500 liters of urine are produced by each person per year, that amounts to the equivalent of 5.6 kg nitrogen, 0.4 kg phosphorus and 1.0 kg potassium.
Dr. Peter Morgan has been working with humanure in Zimbabwe for a number of years

link to his article on urine in agriculture-  www.ecosanres.org/pdf_files/PM_Report/Chapter_10_The_usefulness_of_urine_a.pdf

 Hi Gail thanks so much for sharing. I read your proposal and just brought a few questions to mind. Are folks already using human urine as a fertilizer? What happens to the feces? I know in theory that when an human is healthy their urine is sterile, but I also know (from my father, a urologist) that if folks aren't healthy, their urine in turn, may or may not be sterile. How to do folks work around those sorts of issues?

Very interesting idea though. I'd love to see some of your designs.

Shelton

 GailSwithenbank

Hi Shelton

According to the Swedish Institute for Infectious Disease "Several types of bacteria may cause urinary tract infections. The environmental transmission of these are normally of low importance. E. coli is the most common cause of urinary tract infections, where certain clones may also be associated with gastrointestinal infections. The pathogens traditionally known to be excreted in urine are Leptospira interrogans, Salmonella typhi, Salmonella paratyphi and Schistosoma haematobium (Feachem et al., 1983). There is a range of other pathogens that have been detected in urine but their presence may not
be considered significant for the risk of environmental transmission of disease.
For the urine, mainly temperature and a elevated pH in combination with ammonia have been concluded to affect the inactivation of microorganisms. So far, storage at ambient temperature is the only method practiced to sanitize urine. Increased temperature or pH of the collected urine would further speed up the inactivation of potential pathogens. Recommended storage time at temperatures of 4-20°C varies between one and six months for large-scale systems depending on the type of crop to be fertilized. For single households, urine could be applied to any crop without storage as long as one month passes between fertilization and harvest if fecal cross-contamination is avoided. Dilution of the urine should be avoided.
Guidelines on the Safe Use of Urine and Feces in Ecological Sanitation Systems by Caroline Schönning and Thor Axel Stenström from the Swedish Institute for Infectious Disease Control (SMI
http://www.ecosanres.org/pdf_files/ESR_Publications_2004/ESR1web.pdf

Shelton's question addressed the use of feces. The use of fecal matter as a soil additive is complicated when humanure is from a highly pathogenic population. A thermophilic composting technique must be used where the temperature rise in the compost is sufficient to kill pathogens and feces must be composted and then aged requiring a one to two years cycle. Because of this issue I propose the use of dried feces as a fuel source. Desiccation happens naturally in hot dry climates if the feces are first covered with wood ash after deposit, and then exposed to the air and sun. Addition of ash facilitates
pathogen inactivation and decrease the risk for disease transmission during handling and reuse
of the material. Desiccation of the material and low moisture contents aid to pathogen inactivation. Esrey et al. (1998) suggested that there is rapid pathogen destruction at moisture levels below 25%, and that this level should be aimed for in ecological sanitation toilets that are based on dehydration. Low moisture content is also beneficial in order to reduce smell and fly breeding.
The ash created by the burning of feces provides a fertilizer with phosphorous and potassium.

The heat content of human waste when totally dry, is about 4000-7000 Btu/lb, which is equivalent in heat to lignite coal--also, appropriately, called brown coal.
http://www.straightdope.com/columns/read/2240/can-animal-including-human...

 MaggieSharzan

Great proposal. I love the simplicity of the design, and the fact that it could be constructed by any skill level. I can imagine school children in Africa making the system as a school project and then using the urine on their school garden or for use by a local farmer. It makes so much sense, I wonder why I haven't heard much about using urine as fertilizer through the Permaculture Community since there is so much emphasizes on soil regeneration. Your presence at the Permaculture Convergence should help to educate that community, they sponsor local farmers to attend from all over Africa, as well as the participants from other countries around the world, you could make a great impact!

GailSwithenbank

Hi Maggie,
Great to hear from another Permaculture enthusiast! I wondered about the lack of information about urine as fertilizer from the Permaculture community as well. I studied with Bill Mollison and Geoff Lawton, and have spent time at both of their farms in Australia and neither separate urine. Geoff has a humanure system, which involves composting in a dual chamber, then transfers the compost to a vermacomposting system to be further processed. Both Geoff and Bill also rely heavily on green manure, and nitrogen fixing trees and plants, and fertilizer from their cows and horses as well as chicken and pig tractors to manure the soil and scratch/dig it up.
Bill Mollison was very actively teaching Permaculture in many parts of sub-Saharan Africa starting in 1987, and left many students and demonstration sites to continue teaching his regenerative techniques. It is very possible that the idea of using urine as a fertilizer could be spread through Africa by the Permaculture community through this Convergence, it is the first time the Permaculture community has met in Africa. I am hoping to have the funds to arrive early and to set up a demonstration model so the participants can experience the toilets during the Convergence and the tour of Permaculture sites across Malawi, Zimbabwe and South Africa will be a great chance to further the designs, and to test them in a real-life situation.
Dr. Peter Morgan is in Zimbabwe, he is the leading expert on humanure - perhaps a short sidetrip while in Zimbabwe.

 BobbieS

Can someone explain Permaculture

GailSwithenbank

Permaculture design principles are based on the work of Bill Mollison, a biologist from Australia will field experience in forest regeneration, and the regeneration of macro-fauna, food chains, and water conditions of the inland waters and estuaries of Tasmania. By studying natural ecosystems, Mollison began to understand the necessity for the conscious design and maintenance of agriculturally productive ecosystems that mimic and have the diversity, stability, and resilience of natural ecosystems. An example of his regenerative design principles which he calls Permaculture (derived from the words - Permanent/Agriculture) developed to address the issues of contemporary agriculture and climate change, is a system where 70% of cropland is devoted to forage farming, replacing animal forage grains with nitrogen fixing tree crops, increasing forest cover, adopting low to no tillage on remaining croplands, retrofitting houses for energy conservation, and producing some (if not all) fuel on the farm.

Mollison introduced Permaculture design principles to Africa beginning in 1987 when traveled through Africa meeting with local farmers and surveying ecological issues. During his many trips he trained farmers from South East and South Africa in sustainable farming principles. Many of Mollison's students returned to their villages and towns, and shared their training with local farmers and students who have continued experimenting and developing these sustainable farming principles for the past 22 years. The Convergence in Africa will bring people from these areas across Africa and from other developing and developed countries around the world together to share and compare experiences, the successes and failures over the years of experimentation.

Links and additional information-

EcoSan Res (Environmental Sanitation Research Program) promotes environmental Sanitation in the developing world, and has done great research on humanure systems and use of urine and feces as fertilizer.     www.ecosanres.org/

Guidelines on the Safe Use of Urine and Feces in Ecological Sanitation Systems by Caroline Schönning and Thor Axel Stenström from the Swedish Institute for Infectious Disease Control (SMI
http://www.ecosanres.org/pdf_files/ESR_Publications_2004/ESR1web.pdf

Dr. Peter Morgan has been researching and promoting  humanure from his location in  Zimbabwe for a number of years.   link to his article on urine in agriculture-  www.ecosanres.org/pdf_files/PM_Report/Chapter_10_The_usefulness_of_urine_a.pdf

link to more information on EcoSanitation systems and photos of  proposed designs on my web site at  www.greendesignstrategies.com/id91.html