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__NOTOC__<small-title />[[Image:Struvite.jpg|thumb|right|200px|A jar of Struvite]]Urine is often used as a liquid fertilizer in rural areas due to its highly concentrated nutrient content. The main minerals required by plants are nitrogen, potassium and phosphorus. Urine contains roughly 80% of the nitrogen, 60% of the potassium and 55% of the phosphorus that humans excrete. While nitrogen is relatively easy to obtain from other sources, potassium and phosphorus are more scarce. The only readily available organic source of these is urine. However [[Application of Urine]] is often unwanted since it is required in large volumes, is inconvenient to transport and has a bad odor. Also it cannot be applied through irrigation systems.
<br>
{{procontable | pro=
- It is a biological product and does not contain any heavy metals or pharmaceuticals <br>
}}
===History and social context===[[Image:urine collection.jpg|thumb|right|200px|Man collecting urine in jerrycans on his bicycle]]Pilot studies were conducted by eawag Eawag and UN-Habitat in a peri-urban farming community called Siddhipur in the Kathmandu Valley in Nepal. This was done to investigate the feasibility of urine separation and local struvite production.
The study showed that struvite recovery is indeed feasible and a community wide production programme could generate around 170kg of struvite per year .
===Suitable conditions ===Struvite production is basically suitable in areas where [[Application of Urine|urine application]] is possible. It requires the implementation of EcoSan systems in the community. It might have to be used in combination with other fertilizers, such as the effluent left when struvite is precipitated. This can be used in irrigation systems to directly fertilize crops.
Further for the business model to be sustainable, a local magnesium source is required.
===Technical specification===
====Operation====
[[Image:Struvite production.jpg|thumb|right|200px|Man operating struvite reactor]]For the production of struvite, firstly urine is needed. This can be collected from markets, urinals, public buildings. It must be separated from other sanitation products using [[Urine Diverting Dry Toilet|urine diverting toilets]] or other EcoSan technologies. Then magnesium must be obtained. This can come from bittern from salt production, which contains 3-10% magnesium, or magnesium sulphate from fertilizer powder, containing 5-10% magnesium.
First the reactor is filled with urine. Then the magnesium is added. The molar ratio of magnesium to phosphorus in the urine should be 1:1. Hence the phosphorus concentration needs to be determined and depending on the magnesium source, the appropriate amount added. The mixture stirred manually by rotating the crank handle. This is done for about 10 minutes as the struvite precipitates. After the struvite has settled, the valve is opened to filter out the struvite. This is then sundried. The leftover effluent can be used for irrigation. It is suitable for drip irrigation systems.
====Maintenance====
For the production of struvite it is necessary to manufacture a struvite harvesting reactor. This can be of different sizes depending on the scale of struvite production. The reactor and materials used can be adapted depending on the funds and materials available.
====Estimated Lifespan====
===Cost===
{{Treatment_Cost
* For a 500L reactor in Nepal.
==Country experiences=Manuals= ==External Links==* [https://www.eawag.ch/fileadmin/Domain1/Abteilungen/eng/projekte/vuna/doc/Eawag_News_0115_e.pdf How to produce fertilizer from urine]