Did you know that urine was used to cultivate crops in ancient Rome and China? Farmers in Vermont are now reviving this practice! They think it can increase harvests and make farming more sustainable.

Betsy Williams of Vermont is one of the recipients of the Urine Nutrient Reclamation Program (UNRP) administered by the Rich Earth Institute (REI). She and her neighbors have been harvesting their urine and donating it to nearby farmers for the last 12 years. Approximately 250 individuals contribute almost 12,000 gallons (45,400 liters) of urine every year.

The urine is trucked in and heated to 80°C (176°F) for 90 seconds in a processing facility to destroy bacteria. It is then stored in tanks and subsequently sprayed onto land for crops to grow.

Why use Urine?

Urine is full of nitrogen and phosphorus, the very same vital nutrients found in chemical fertilizers. While synthetic fertilizers have negative effects on the environment, though, those derived from urine are not. Nitrogen-based fertilizer production depends on fossil fuels, and phosphorus extraction creates poisonous waste. Urine is a natural and free resource, in contrast.

Studies indicate that fertilizing with urine can increase the yield of crops such as kale and spinach by over two times, even in low-quality soil. Farmers can produce healthier crops while minimizing pollution.

A better alternative for the environment

Today, the majority of the nutrients in human waste go into wastewater. Urine is diluted with water when flushed down the toilet, treated in treatment plants, and then discharged into rivers and lakes. This is an energy-intensive process that frequently does not eliminate all the nitrogen and phosphorus. When these nutrients reach waterways, they nourish algae, causing toxic algal blooms that kill fish and destabilize ecosystems.

By piping urine onto land rather than into waterways, Vermont's system avoids pollution and aids in plant growth. "Wherever you put nitrogen, it's going to help plants grow. If it's in the water, it helps algae grow. But if it's on the land, it helps crops grow," explains Jamina Shupack, REI’s executive director.

The REI crew makes sure urine is applied at the optimal time when plants can take it in most effectively. They also monitor soil moisture so that runoff into adjacent waterways is avoided. While some runoff is unavoidable, the overall effect is significantly lower than with chemical fertilizers.

While Vermont is pioneering in the U.S., the same is being done elsewhere in the world. In Paris, individuals are given urine to be used to fertilize wheat that is used to make baguettes and biscuits. In Sweden, researchers are developing a system to harvest urine and convert it into fertilizer. Peecycling initiatives are also being undertaken in South Africa, Nepal, and Niger.

Challenges in expanding peecycling

Even more farmers would like to utilize urine as fertilizer, but it is hard to scale up collection. Regulation is one of the main challenges. Urine doesn't fit into the current legal categories in Vermont, so it's difficult to obtain proper permits. To overcome such challenges, REI works together with regulators and septic waste haulers to comply with legal standards.

Urine transport is also a problem. Since it is heavy and has a large volume, it is expensive to transport long distances and produces emissions. To address that, REI created a freeze concentration system, which concentrates urine by six times, allowing transport to be more efficient. Testing of the system is ongoing at the University of Michigan.

Fertilization with urine can transform agriculture. Farmers can use a freely available, natural resource to lessen their dependence on chemical fertilizers, save water sources, and produce healthier plants.

As Betsy Williams sums it up, "Everybody pees. It’s an untapped resource." With greater public awareness and regulations, urine could become an accepted and sustainable practice for farming everywhere.

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