Human Urine in Hydroponics
We see that water scarcity and water pollution are increasingly causing serious health and environmental challenges throughout the world. An important reason is that a good infrastructure is often absent to discharge the waste water responsibly. There is too little circular thought about water. The future wastewater infrastructure should therefore be seen more as a combined recycling plant & wastewater treatment plan, and depending on local needs and constraints. Some regions are faced with water stress and groundwater depletion because of climate changes, population growth, and the frequent occurrence of drought (low rainfall). A first step could be that we collect domestic waste water in a special system and separate toilet waste. Gray water comes from the kitchen and sinks, shower and laundry, while black water consists of urine, faecal material, toilet paper and rinse water from the toilet. It is a pity that this innovation in housing construction is still not being picked up. It is not even in the picture of the government and environmental clubs. And yet this different view on our water use would yield economic and sustainable profits.
Urine use centuries old
The use of urine as a plant fertilizer in soilless systems can currently be found under the names peeponics, bioponics and recently also Anthroponics. The lattest was recently presented at the Dutch design week in Eindhoven (2108), and shows that it is possible in this way to have a renewable, soilless cultivation system that uses natural bacterial cycles to convert urine into plant manure. It is not only a system, but Anthroponix is also a transdisciplinary research and design collaboration from Eindhoven. (https://anthroponix.org/) The system is a combination of aquaponic agriculture, organic hydroponics and wastewater treatment. Most hydroponics systems use mineral-based nutrient solutions of fossil fuels. Anthroponix instead uses bacteria to break down organic material from human urine in a mineralized form that can take root hair (rhizoids) from plants. For plants with a high nutrient demand, traces of pure wood ash and kelp flour are added to replenish potassium and magnesium. The nitrogen in the urine in the form of urea, creatine and ammonia and when mixed with carbon-rich materials ensure that the aerobic bacteria make the nitrates that can be absorbed by the plants. A project that was also on the Design Week and goes beyond urine, namely all human waste materials used. It is clear that urine is very effective and is again in the spotlight. Again, because the concept has been around for a while. It is already known that tomatoes grown on hydroponics with urine tastes even better than without. A large project (The STUN project 2015) in Nepal also shows that it is possible to grow tomato plants entirely on the basis of human urine fertilizers. https://youtu.be/A8F3KcIgscg
The logic is straightforward. Urine contains a high percentage of ammonia plus phosphorus and trace elements. With only a small biofiltration, urine is converted into a more vegetable-available nitrate with NPK values that compete with other fertilizers. The relative ratios are typically about 11 parts nitrogen to 1 part phosphorus to 2.5 parts potassium. Studies conducted in Sweden (Sundberg, 1995; Drangert, 1997) show that the urine of an adult contains sufficient nutrients to fertilize 50-100% of the crops needed to feed an adult. Our food consists of nutrients with a high protein content and different forms of nitrogen, phosphorus and potassium. While the solid stool contains part of this NPK, most of it ends up in the urine. The human body ultimately uses only 15% of the dietary intake, which means that up to 85% of the nutrients can be ‘disinfected’ and used. Basically, 95% of the 0.8-1.5L urine that each person produces per day is water. The last 5% consists of both the macronutrients that all growers know – nitrogen (s), phosphorus (p) and potassium (K) – as well as some traces of micronutrients. Although the actual content will vary slightly because it depends on a person’s diet.
The average person produces enough urine per year to cover 300 – 400 m2 of soil to a level of 50 – 100 kg / ha of nitrogen. Slowly this is starting to be used within permaculture. Although historically urine has already been used as a vulture for the country. And then stored in the cesspit. In several countries there is already a market that sells urine to farmers (see fig.2) In the past, in China the manure was collected in terracotta jars of 250 to 500 liters, which were transported closed. Every year more than 182,000,000 tons of human manure was collected in villages and towns, resulting in 1.160,000 tons of nitrogen, 376,000 tons of potassium and 150,000 tons of phosphate in the form of compost being returned to the agricultural land. Very fresh human urine is sterile and free of bacteria. It could be drunk like that. I would be careful with it, because of possible bacteria, germs etc. In some countries it is therefore stored. Six months of storage in a tank is sufficient. Urine older than 24 hours can go to the compost heap. Fresh urine (i.e., less than 24 hours) must be diluted. There are different views on the extent to which it has to be diluted: one says 1 part of urine on 4 parts of water, and the other 1 of 10-15 parts of water for young plants.
Some of the annual values of the nutrients are:
According to Ir.Wouter de Heij from the article “Our own poo and piss can save our world” the following quote:
“If we add up the ‘production’ of all Dutch people (16.6 million inhabitants) and Belgians (10.4 million inhabitants), and take the figures of King for the West as a starting point, this amounts to 135,000 tons of nitrogen per year, 54,000 tons of potassium and 40,500 tons of phosphate, which is probably a big underestimate, given the much changed dietary pattern since then.The prices for these substances fluctuate strongly (depending on the oil and gas prices), but even if we take the low prices from early 2007 ($ 280 per tonne of nitrogen, $ 260 per tonne of phosphate and $ 170 per tonne of potassium) corresponds to a total amount of 57.5 million dollars or 41 million euros that we literally wash annually by the toilet. At the beginning of 2008 the prices for artificial fertilizer were four to five times higher and with the exhaustion of fossil fuels the value of these raw materials can only increase”.
Given the enormous amount of urine excreted by 7 billion people every day, it is a miracle that this source of urine fertilizer has not been capitalized on a larger scale. Instead of importing nutrients for gardening and exporting nutrients through the toilet, we can help to close this loop by keeping our urine in the local food cycle. It can be particularly beneficial for fertilization in urban environments where other local forms of fertility may be scarce due to a lack of green spaces. A good example is of course the water purification plant from Amsterdam that removes phosphorus from the urine and specifically makes struvite. This is a phosphorus compound that can be dried, stored and applied to the soil as a self-sustaining, sustainable method to obtain phosphorus. Struvite ((NH4) Mg PO4.6H2O) is a mineral composed of ammonium, phosphate and magnesium and excellent for use as a fertilizer. Necessary because worldwide a phosphor scarcity threatens and the demand of large hydroponics companies increases enormously. That is also one of the reasons that current hydroponic cultivation is absolutely unsustainable. It causes an environmental problem, namely the physical depletion of global phosphate reserves. This plays a much longer term than eutrophication. The phosphates themselves do not disappear, but become so dispersed and diluted that they become depleted in concentrated and usable form for all kinds of applications. Once they end up in the ocean, the concentrations are too small to win them. In addition, this scarcity is reinforced by the geographically uneven spread of phosphate rock. Morocco, with its 74%, produces the most phosphorus. The danger of political or economic change has far-reaching consequences for agriculture and horticulture in the world. Finding a simple alternative to urine can be a step towards a more sustainable and independent local production of phosphorus.
The first study evaluates the use of human urine and wood ash as fertilizers for tomato cultivation in a greenhouse. Tomatoes were grown in pots and treated with 135 kg N / ha applied as mineral fertilizer, urine + ash, urine only and a control group (no fertilization). The plants fertilized with urine produced equal amounts of tomatoes as the mineral fertilized plants and 4.2 times more fruit than non-fertilized plants. Lycopene levels were similar in tomatoes from all fertilization treatments, but the amount of soluble sugars was lower and Cl- was higher in urine + ash fertilized tomato fruits. The content of β-carotene was larger and the NO3 content was lower with tomatoes fertilized with urine. No enteric indicator microorganisms were detected in the tomatoes. The results suggest that urine with wood ash can be used as a replacement for mineral fertilizers to increase the yield of tomatoes without causing any microbial or chemical risks.
Not only ash but also rice
The research to make urine fertilizer because it is rich in nutrients is also in the research of Hashemi S1, Han M1. from 2017 worth to read. He indicates that we should not direct the urine directly to a water purification plant, but first by adding solid additives such as dried rice in powder form to help the process of harvesting the nutrients from the urine. In this study, the procedure and efficiency of the use of rice powder for harvesting nutrients were examined by following the reductions in ammonia, phosphate, magnesium and calcium ions and identifying the harvested nutrients using crystallographic methods. The results show that the ammonia, phosphate and magnesium ions showed comparable reduction trends. However, the reduction process was limited by the availability of magnesium and phosphate, which reduced the efficiency of harvesting nutrients. The nutrients that were harvested with the rice powder were identified as mainly struvite. It was therefore advisable to balance the phosphate and magnesium ions with ammonia to improve the efficiency of harvesting nutrients.
Another study has shown that phosphorus recovery from the hydrolysed urine could be achieved by induced struvite precipitation using seawater as a magnesium source, while nitrogen harvesting was achieved by air stripping and subsequent acid adsorption (Liu et al., 2013Liu et al., 2014). Afterwards, the hydroponic system was used to further polish the urine drain flow in order to meet the discharge standards (Yang et al., 2015).
Already in 2016, Bio-designers Sarah Daher and Markus Wernli, a social design researcher, were busy initiating the project Harboring Organisms, Sharing Tensions (H.O.S.T). This research focused on purifying urine as a nutrient for plants. During the research, test subjects are encouraged and enabled to purify their urine, via fermentation techniques, to nutrients for growing plants. With this, the designers aim, among other things, to make taboos about human waste materials negotiable. Part of the research is done during a residency at Utopiana in Switzerland. In addition, various demos with test subjects are organized in, among others, the Korea Research Institute of Chemical Technology. The initiators work together with microbiologists from Hong Kong and TU Delft, biologists and other experts at both scientific and design level. HOST resulted in a so-called ‘Anthroponics Plant Cultivating Kit’, a DIY package so that people can purify their urine at home and plants can grow, a touring ‘HOST Demo Lab’ focusing on activation workshops in the Netherlands and an anthropological film about the project with which the knowledge can be unlocked worldwide. The follow-up to this initiative is Anthroponic. (https://anthroponix.org/)
The Swedish International Development Cooperation Agency (Sida) carried out agricultural trials in India in 2014 to test the benefits of harvesting urine for more sustainable agriculture. The pilot project in the district of Nalanda, in the state of Bihar, focused mainly on overcoming the prejudices about urine, to realize the potential economic benefits of ecological sanitation (ecosan) for local farmers. It introduced urine exit facilities and tried to introduce human urine as a valuable agricultural resource: an effective, safe and free alternative to commercial chemical fertilizers and thus an impulse for a better livelihood. This approach led to the introduction of urine crops in the vicinity of the communities, and may have paved the way for the introduction of more comprehensive sustainable sanitation. To learn more about the SEI-WASHi collaboration visit http://www.sei-international.org/projects?prid=2070. You can also download it https://www.sei.org/mediamanager/documents/Publications/sei-fs-2014-biharecosan-bind.pdf.
The RUAF foundation, a global partnership for sustainable urban agricultural and food systems from Leusden, has also researched “Introducing Urine as an Alternative Fertiliser Source: Case studies from Nigeria and Ghana”. With the same goal to collect and use human urine in the right way for agriculture. Moreover, it contributes to a better environment, sanitation in cities and reduces the costs of plant production. The innovation lies in the integration of agriculture, environment and sanitation. https://www.ruaf.org / introducing-urine-alternative-fertilizer-source-case-studies-nigeria-and-ghana
There are of course a number of conditions that you have to ask otherwise there will be problems. For example, with regard to the use of urine as a food source in a hydroponics system, you must set strict conditions for what people eat. The release of persistent organic pollutants, drugs and trace metals in human urine is not desirable. Although urine itself is not very dangerous, some precautionary measures have to be taken to ensure safety. The World Health Organization (WHO) has developed a barrier system to prevent the spread of diseases. The barrier system is quite simple and requires no special skills or tools. The first barrier in the WHO process is the source separation. This happens at the level of the household where urine and faeces are separated by a toilet that diverts the urine. The urine is then collected and stored. Everyone involved in dealing with the urine must wear rubber shoes and gloves. The third barrier is the application technique: placing the urine directly in the soil so that it does not end up on the above-ground parts of the plant. Fourth is selective application. The use of urine on the land is of course different than on the basis of hydroponics.
Another safety risk is how urine is stored. Only use sealed containers, otherwise you risk mosquito larvae. Although the urine is quite sterile when it is fresh, there are some organisms that live in it. These usually disintegrate when they are applied to the ground, but the storage process ensures that these organisms are all dead. Such an organism that can live in the urine is Salmonella typhi / paratyphi, although it is of short duration – requiring only 1 week of storage to reduce their number a thousand times.
A World with clean water and fertile soil, achieved by recovering the nutrients from our bodies as elements in our life cycle. It is clear that urine has already been proven worldwide in agriculture as a valuable form of fertilization. The idea and the will to use this will take years. Still, I hope that initiatives such as the urine-rinsing flush toilets with a special urine receptacle in front of the toilet bowl, from the Rich Earth Institute’s and the Anthroponix’s initiative , make urine available for hydroponics. Otherwise ultimately people who thrown urine away thrown money away. A test for large-scale use within the hydroponics could be a breakthrough. It you have some additional information we would like to add this to this article
©Ed van der Post www.hydroponics-nederland.nl