On a Wednesday evening in France, Nicolas nestles two jugs of yellow liquid into his bike panniers and rides to a small warehouse where he’ll get produce from a local farmer. After he picks up carrots, greens and potatoes, Nicolas leaves something for the farmer: his urine.

France has thousands of CSAs — community supported agriculture programs — that link farmers to urban consumers who want fresh food and a closer connection to the land. In 2024, twenty CSA members in Châtillon, a Parisian suburb, tightened that connection by donating urine as part of a pilot project to return nutrients to the farm that provides their food.

View of farmland. — Vegetables, grains, and flowers are grown at the CSA farm outside Paris that participates in the peecycling project.

The project, dubbed Enville (in the city), was created by Louise Raguet, a designer for a university-based program called Ocapi. Raguet knows that keeping human-generated nutrients out of the waste stream will help a city plagued by climate change, agricultural runoff, and wastewater overflow from 10 million inhabitants. For years she has focused on simple ways to divert urine from the suburbs, all while collaborating with farms, agricultural agencies, water and waste entities, and CSA members.

Before launching Enville, Raguet got input from members of “Radis Actifs” (Active Radishes) the CSA that was interested in participating. These peecycling volunteers helped shape the project, from urine drop-off, to collection to delivery.

Consumers and peecyclers would bring urine in jugs to a small depot at the CSA vegetable pickup spot, where the delivery farmer could take the pee back to the farm.

The power of pee

The consumer & peecycler circuit is on the left: they bring urine to the dispatch location (center) and pick up their vegetables. The farmer’s circuit is on the right: a truck loaded with vegetables (top right) delivers them to the dispatch location, where the farmer picks up urine.

Perhaps you’re wondering, “Why bother? Simply fertilize fields with commercial fertilizer!” Certainly many farmers do that, but commercial fertilizers end up in waterways, groundwater, and other places where they don’t belong, causing excessive growth of algae and other plants, and polluting drinking water. France is interested in domestic sources of fertilizer for a number of reasons — fertilizers are costly for farmers and energy-intensive to produce, requiring imported natural gas. In addition, phosphorus, a key component, is a diminishing resource.

Human urine is packed with the nitrogen and phosphorus that crops need, so using it could save farmers money and divert it from sewers and septic systems, thus keeping it out of the waste stream. Peecycling returns urine to the earth, completing the cycle of plants taking up nitrogen and phosphorus, then humans eating those plants and excreting the nutrients that are needed for plant growth.

Some peecycling programs require volunteers to drive to depots where they can drop off their containers of pee. Returning urine to a CSA, however, saves transportation time and fuel for both CSA members and the farmer, who will make the trip anyway.

Many ways to collect the liquid gold

One of the first challenges Raguet faced was how to collect the peecyclers’ urine. She sought simple, low-cost items: five-liter (1.3 gallon) plastic jugs (from used cleaning products) fit the bill. These jugs are readily available and easy to carry. Next, Raguet designed and 3-D printed a funnel to screw onto the opening, plus a cover to prevent odors when not in use.

White funnel on top of white jug. — Plastic 1.2-gallon collection jug with screw-on funnel and cap.

Person in red shirt holding a tube over a clear jug. — Raguet pumps urine from a donor’s jug to a holding tank. Air vents to the outside and she assures us, “There’s no smell.”

Participants could also use other options, such as a funnel in a bottle or a nuns cap (urine specimen collector), which sets into the toilet seat.

Another design challenge was how to transfer the small jugs of urine into the larger tank. To develop a pump system, Raguet drew concepts from the Guide to Starting a Community-Scale Urine Recycling Program, produced by the Rich Earth Institute in Brattleboro, Vermont. The design avoids releasing unpleasant odors by pumping urine from the jugs through a hose into the tank.

The same pump fills two tanks built into the CSA delivery truck to transport urine to the farm. There, it’s pumped into larger tanks. Enville collected 1,585 gallons (6,000 liters) this way in 2024.

Once urine reaches the farm, it’s stored for six months to kill potential pathogens (a process recommended by the World Health Organization). Then the urine is ready to use as a fertilizer. For now, the team has been spreading it on wheat fields and has seen a marked increase in the growth, which has spurred the farmer’s interest to continue with the project.

Green field of wheat. — Look what pee can do! The diagonal wheat strip was fertilized with human urine and grows taller and greener than the rest of the field.

The future for pee-cycling on farms

In the future, the farmer involved with this project plans to fertilize vegetables and should be able to accommodate the urine donated by up to 50 peecyclers — even more if they bring donations to a depot at the farm. To that end, Enville plans to continue partnering with “Radis Actif” in 2025, and five more CSAs are interested in peecycling.

In the U.S., the idea hasn’t caught on, but a few CSAs are intrigued, and might be inspired by Enville.

For more information: https://www.leesu.fr/ocapi/les-projets/enville/

Photos provided by Louise Raguet, OCAPI