French researchers have revealed that urine could be a unique natural alternative to chemical fertilizers, hence the future of organic fertilizers.
Synthetic nitrogen fertilizers boost agricultural production, but they pollute the environment if used in excess. Their prices are also soaring, especially now with the war in Ukraine. It has left scientists searching elsewhere for a solution to this combination of crises.
According to these scientists, urine’s usage would reduce environmental pollution and help to feed a growing global population.
To grow, “plants need nutrients, nitrogen, phosphorus, and potassium,” explains the engineer and coordinator of the OCAPI research program, researcher Fabien Esculier. “When we eat, we ingest these nutrients and excrete them, mostly through urine,” he added.
Urban excrement was used in agricultural fields for a long time before being replaced by chemical fertilizers. But when these nutrients are released in large quantities into rivers, they are one of the primary sources of pollution.
Going beyond presumptions
Separating and collecting the urine at the source means rethinking toilets, the wastewater collection network – and overcoming specific preconceived ideas.
The separation of urine from toilets was first tested in Swedish eco-villages in the early 1990s, then in Switzerland or Germany. Experiments are also being carried out in the United States, South Africa, Ethiopia, India, and Mexico. In France, projects are emerging in Dol-de-Bretagne, Paris, Montpellier.
The first generation of toilets with a urine separator was considered impractical and unsightly. However, a new model developed by the Swiss company Laufen with Eawag has got good reviews.
Fabien Gandossi, who owns the 211 restaurants in Paris, equipped his establishment with this new, dry model that collects urine.
“We have rather positive feedback, people are a little surprised, but they see little difference compared to a traditional system,” he says.
Urine requires low processing for use in agriculture
There are differences in attitude across the countries where urine-based fertilizers have been trialed. The acceptance rate is very high in China, France, and Uganda but low in Portugal and Jordan.
Since urine is not usually a primary carrier of diseases, it does not require heavy processing for use in agriculture. The World Health Organization (WHO) recommends letting it rest, and it is also possible to pasteurize it.
Once collected, the urine must be transported to the fields. But the procedure is still expensive. Various techniques make it possible to reduce its volume, concentrate, or even dehydrate it.
There are a lot of obstacles, with soaring gas prices and the desire of many countries to strengthen their food sovereignty. Despite this, researchers believe that urine is the future of natural fertilizers. Should Ghanaians return the nutrients in their urine to the farm?
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