Yes, it is possible! There are techniques to transform theurine In fertilizer, thus trying to exploit it in the best of farms according to principles of circular economy. THE’urine is a pollutant And it must therefore be disposed of, but by chemical composition it is also a potential source of nitrogen, phosphorus And potassiumessential elements for plants, widely used in agriculture. So, given its composition, urine can become a sustainable option to get an excellent one fertilizer. If the solution is simple from a chemical point of view, it is actually quite complex to put into practice. That’s why researchers and technicians all over the world have been experiencing new methods for over 10 years to collect it and separate it from other dejections. For example, the Swiss Federal Institute of Aquatic Science and Technology and the University of Henan have found ways to transform urine into “Golden fertilizer“.
How our pee is made and why it is useful for plants
Our pee is composed for the 95% of water and for the rest of organic substances e mineral salts. The most percentage mixture is theureaorganic molecule consisting of nitrogen, hydrogen, carbon and oxygen. In urine they are also present phosphorus And potassiumalthough in clearly lower percentages compared tonitrogen. The average ratio is 11 parts of nitrogen, 1 of phosphorus and 2.5 potassium. These three chemical elements (n, p and k) are fundamental in the growth of plants: nitrogen (N) is the basis of the Synthesis of proteins potassium (k) is involved in the production and transport of sugars, in enzymatic activation and protein synthesis, phosphorus (P) is used as a phosphate and is important in the process of the photosynthesis.
To date, the production of synthetic fertilizers containing these elements is extremely expensive not only in economic terms, but also as an impact on the environment:
- THE’nitrogen It is produced through an expensive chemical process, called haber –bosch, which transforms atmospheric nitrogen into ammonia;
- The potassium It is obtained from the potassium chloride mines;
- The phosphorus It comes from phosphate rocks and is stored in the form of phosphorites, whose reserves are found in a limited number of countries in the world.
How to transform pee into fertilizer, the recycling of urine
Urine represents less than 1% of the volume of domestic waste water, therefore, the first goal is to adopt a method for separate it and concentrate it. The most popular experimental methods to date provide for the use of toilets that allow the separation of urine from other dejections without the use of water: this allows the recovery of nutrients and water saving.
Precisely for this purpose in 2019 in France one was founded start -up for the storage and the Recovery of human urine in agriculture. Special bathrooms have been patented which allow the collection of pee separately and without water consumption and have been installed in public places very popular. Subsequently the urine is filtered and purified through a process of fermentation To then become a culture ground for bacterial strains of agronomic interest. To date, the company deals with 11 thousand liters of urine a year and has calculated that with 1.2 million collected urine can be fertilized 45,000 hectares of land.
Since 2015 also the Swiss Federal Institute of Aquatic Science and Technology (EWAG) patented a concentrate fertilizer based on urine; With an innovative technique that always begins with separate collection in special dry toilet. The Institute managed to produce 100 liters of fertilizer A thousand liter liquid of urine. Today this product is regularly marketed. In Sweden, In a village near Stockholm, A complex of 44 houses was equipped with toilets with separators. Urine, collection through separate pipes, it comes storage in tanks and then used as fertilizer. The use in experimental vegetable fields gave satisfactory and without any health risk for the transmission of pathogens.
Another important milestone in this area was obtained by a Chinese team of theUniversity of Henan: the researchers found that, adding to urine oxygen and a catalyst graphite (a substance capable of speeding up the reaction), a chemical -rich chemical is produced percarbammide (Carbamide peroxide). The process requires only a few passages and does not produce waste: just place thin graphite sheets on an electrode in a concentrated solution rich in urea and, through electrolysis, percarbamide crystals are formed. The substance proved to be a great fertilizer Able to help wheat plants, peanuts and lettuce to grow higher than when they were cultivated with the use of a normal fertilizer for urea.
