At one point in the tour, the owner of the property stopped at a small shack. He pulled back the curtain to reveal a toilet made from a plastic bucket. He held up a finger and said something stern in Spanish. My wife leaned in to translate.
“This bathroom is only for peeing.”
We were traveling through Chile and staying at a Workaway site for a few weeks. Whatever the place was called in Spanish, it was essentially a hippie commune in the middle of the desert mountains run by a man who apparently didn’t take a divorce well. While there, we helped pick vegetables and build a shed out of mud and cattle manure. After following the black pipe from the bathroom shack to the orchard, I realized we were also tasked with nourishing the lemon trees.
Using human urine to fertilize crops traces back millennia, but it has recently been given more attention following rising fuel costs and greater environmental concerns. Experiments on replacing synthetic fertilizer with human urine have been increasingly conducted all over the world, but one of the major centers for research is in France. One prohibitive issue in the past was that it was difficult to isolate urine from the waste system. However, the recent invention of a urine-separating dry toilet by a Swiss company has made that possible without an unsightly experience in the bathroom. Presently, a variety of bars and music festivals near Paris use this toilet to supply research facilities with the urine of their patrons.
One advantage of urine is how little processing it requires. Because of the high ammonia content, it is mostly sterile as it leaves the body. Studies have shown nearly all bacteria that is present when first produced is naturally killed by leaving the liquid to sit for several months. Previously, scientists were concerned human urine would contain antibiotic-resistant bacteria that would be transferred to the plants, but it appears this threat is eliminated by letting it remain in storage before application to the fields.
The National Institute of Agricultural Research of Niger has also studied the use of human urine in recent years, largely assisted by a volunteer group of Niger women. While women make up a larger percentage of the agricultural workforce in Niger, they typically do not have access to the more profitable land, nor control what happens to it. Particularly in more remote regions, the land has become nutrient-depleted while trying to grow pearl millet, the country’s staple grain. These women, in conjunction with the research institute, have found a 30% increase in yield over a three-year period by applying the urine of people. Like in France, they too first stored the urine for two to three months. In taking the lead on the initiative, it is also suggested that this group of females has gained a sense of autonomy from the project, being able to demonstrate their leadership skills. Having validated the benefits of urine, the coalition of the institute and the volunteers is now focusing on the cultural and social acceptance of its use.
French researchers have found that yields with human urine were nearly as good as crops supplemented with industrial fertilizer, causing some to be optimistic about its widespread use in the future. As petroleum grows scarcer, the steady availability of urine becomes increasingly attractive. It is estimated that if 10% of Americans save their urine, it would produce 330 tons of nitrogen and 20 tons of phosphorus. Nonetheless, such a system is not without its challenges. At the moment, it is still expensive to collect and transport human urine. If it is to be used on human foodstuffs in the future, it will have to overcome a “perception problem,” as it may take the general population time to come around to the idea of eating something that has been peed on.
I’ll admit, one night at the desert commune, I took a moment to marvel at the synergy of it all. The more sangria I drank, the more nutrients I had to give to the lemon trees that contributed to the sangria. That only motivated me to drink more sangria, so I could do even better for the trees. Being eco-conscious felt good … until the morning.
There still may be some problems to figure out before large fields of crops are sprayed with toilet water, but the science seems promising thus far. It appears Mother Nature has a gift we haven’t taken advantage of yet. If using human urine can lower fertilizer costs and reduce the need for waste treatment, it just might be the “number one” option going forward.
