Can Human Urine Replace Chemical Fertilizers? - Modern Farmer

Can Human Urine Replace Chemical Fertilizers?

Urine contains nitrogen, phosphorus and potassium -- essential plant nutrients that are usually mined from the earth or the air for agricultural use. The Rich Earth Institute is collecting thousands of gallons of urine, hoping to make potentially harmful waste substance into a boon for crop production.

The Rich Earth Institute in Brattleboro, Vermont, is likely the only organization measuring success in gallons of urine.

In 2012, Kim Nace, Rich Earth’s administrative director and partner Abe Noe-Hays collected 600 gallons of urine from friends and neighbors. The next year, the organization brought in about 3,000 gallons from 170 human volunteers. Rebecca Rueter, a board member for Rich Earth, invited members of the local women’s chorus to donate their pee.

Rich Earth hopes to double that amount this year to a round 6,000 gallons — enough to fill a third of an average American swimming pool. “We’ve given volunteers a few things to make it easier — some funnel devices and things like that,” says Nace.

Urine contains nitrogen, phosphorus and potassium — essential plant nutrients that are usually mined from the earth or the air for agricultural use.

The project aims to test human urine as a replacement for chemical fertilizers. Urine contains nitrogen, phosphorus and potassium — essential plant nutrients that are usually mined from the earth or the air for agricultural use. In collecting human urine, Rich Earth is diverting the same chemicals from waterways to farms, making a potentially harmful substance a boon to crop production.

The urine collection scheme has had some unintended consequences for Nace’s home in Brattleboro, which hosts the so-called “urine depot.” There is a buzz of conversation as volunteers drop off 5-gallon jugs to be loaded into larger holding tanks. “When people realize that they produce something every day that can be helpful to the environment and the earth, it’s a very wonderful feeling,” says Nace.

[mf_list_sidebar layout=”basic” bgcolor=”#0089c6″ title=”Poop Versus Pee as a Fertilizer” separator=”no”]

[mf_list_sidebar_item]“Urine Separation — Closing the Nutrient Cycle,” the exhaustive Swedish study of using urine as a fertilizer, compares the pros and cons of using solid human waste and liquid human waste to help grow crops. According to the study, urine contains many of the chemical elements plants need, but solid waste has the lion’s share of organic material such as carbon, fiber and beneficial microorganisms. [/mf_list_sidebar_item]

[mf_list_sidebar_item]At the moment, solid human waste is much more likely to become fertilizer in the U.S. Despite strict regulations from the EPA, almost 50 percent of “human biosolids” return to farmland in the states. As far as Rich Earth knows, they are the only project in the country legally returning human urine to the soil.[/mf_list_sidebar_item]

[mf_list_sidebar_item]Which is surprising. Fecal matter requires a much greater amount of attention to be processed into safe fertilizers or grey water. On the other hand, urine only makes up 1 percent of the liquid sewage flow in Sweden, and it’s rarely separated from the rest of the stuff that gets flushed and turned into fertilizer. To capitalize on the plant nutrients in urine, the liquid would need to be separated at its source rather than processed at a treatment facility.[/mf_list_sidebar_item]


Jay Bailey, who owns and operates Fair Wind Farms with his wife Janet Bailey, volunteered a few hay fields for the initial stages of the project in 2012. He spread a urine solution from the Brattleboro volunteers over the crops from a horse-drawn applicator and, come harvest time, observed that urine-treated fields were twice as productive as unfertilized controls. The success earned Rich Earth a $10,000 SARE grant from the USDA to expand the trials at Fair Wind in 2013. This year, urine will go to three farms for collaborative trials.

But would Bailey — who makes his living operating a small farm — opt for pee-power if he wasn’t part of an experiment? “With the cost of fertilizer these days, I would certainly give it very serious consideration,” he says.

Across the Atlantic, studies have long established urine as a powerful fertilizer. A study conducted by the Stockholm Water Company in the late 1990s diverted urine from four housing projects to a grain farmer outside the city. The scientists concluded not only that urine could replace quick-acting mineral fertilizers, but also calculated that one Northern European adult pees enough plant nutrients to grow 50 to 100 percent of the food requirement for another person. Other successful trials have taken place in China and Mexico, though none as detailed as the Swedish one.

Rich Earth acknowledges that the biggest hurdle to their work is public perception of lingering buckets of pee, or the so-called “ick factor.” Urine is actually sterile when it exits the body, save for rare cases of a bladder infection or salmonella poising. REI has nevertheless developed two strategies for eliminating the risk of pathogens, either by solar pasteurization or long-term storage in a warm greenhouse. Both have proven effective.

A real concern for Rich Earth? Left over pharmaceuticals that end up in urine. The EPA has selected Rich Earth for funding to conduct a study of traces of drugs in urine with the help of the University of Michigan and SUNY Buffalo.

But even if there is minimal risk to personal or public health, Nace realizes that only a chosen few will ever be willing to collect their own urine with jugs and funnels. A much more realistic option is urine-diverting toilets, which again the Swedes, masters of pee, have reliably engineered.

[mf_mosaic_container columns=”3″ captions=”yes”]
[mf_mosaic_item src=”” number=”1″ caption=”Volunteers find the optimal dilution rates for 2013 field trials.”]
[mf_mosaic_item src=”” number=”2″ caption=”A greenhouse built to treat urine tanks for pathogens. The urine is sanitized after 30 days at or above 20°C (68°F).”]
[mf_mosaic_item src=”” number=”3″ caption=”Board member Dan Marks and Research Director Abe Noe-Hays built a solar pasteurizer in 2012 to sanitize 50 gallon batches of urine.”]
[mf_mosaic_item src=”” number=”4″ caption=”Over 170 volunteers have donated urine to the project. Photos and captions courtesy of the Rich Earth Institute.”]

Nace keeps one in her home, where it’s become something of a tourist attraction for people coming to learn about the project. (She welcomes everyone to use her bathroom, but appreciates a donation in return.) The toilet has a division three-quarters of the way toward the front of the bowl. Urine goes in the front side where it’s piped to a holding tank; all other waste and toilet paper falls to the back for composting.

The only complaint on the toilet, says board member Konrad Scheltema, is that the men have to sit to use it. Then again, the requirement keeps Nace’s bathroom clean.

Vermont might be one of the more progressive states in the country, but even as regulators and politicians support the project, there remains a fair number of skeptics coming to Rich Earth with questions. Does it smell? Sure, says Bailey, but only for about an hour after application. Any ammonia-based fertilizer smells. Is it legal? Rich Earth has met repeatedly with Vermont’s Agency of Natural Resources, which oversees waste water management, to make sure they are meeting all public health standards.

Most inquires come from people worried they are literally pissing away a valuable fertilizer, all with the same question: How can I help?

Nace refers all potential urine donors to the Rich Earth website.

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Ronald Johnson
5 years ago

I use my urine diluted 8 to 1. 1 quart of urine to 2 gallons of water on my entire yard and lawn. Plants explode with flowers and grow rapidly. I also add a little wood ash to the urine to up the Potassium levels. Apply to lawn after watering while foliage and ground are still wet.

Jo Brownold
5 years ago

Gardening in Mexico in worn-out soil – no earthworms! – two weeks later, leaves are all deep green, almost all plants showing new growth. Hooray for pee!

5 years ago

There is a book written on the subject. “Liquid Gold” by Carol Steinfeld, published by Green Books

Shairn Villa
5 years ago

I have been saving urine to boost my compost bins. I also add whey, liquid left from steaming veggies, kombucha that got too sour, and soy whey from making tofu, when I have it.
I was surprised and intrigued when I poured the collection jug onto my compost bin this morning to find no unpleasant odor and a large healthy looking kombucha mother come sliding out. Could kombucha Scoby help break down urine to make it less nasty and more useable ? It would still be acidic, and need diluting but the fact that it smells pleasant made me wonder.

ron renkoski
5 years ago

How much elemental nitrogen is in each gallon of human urine?
How much of each N containing anion?

Brij lal yadav
5 years ago

Dear Sir
Greeting of The Day
My Self Yadav from India New Delhi
i want to know .is it Possible Human Urine convert into Crystal sap and used Horticulture

4 years ago

Ive been using urine for the pazt 6 yrs. With stunnig results to my medical cannibis crops! Thank you for the great info. Looking forwarx to your results in the years to come…

5 years ago

Yes I think it can this is the third week I have been experimenting in my garden then decided to check the internet for information just incase I was doind the wrong thing only to find out that I was not the first one, thanks alot for the ratio of the mixture, I wadixing tree litres to fifteen litres of water.

Mulindwa Boaz
4 years ago

i am so excited about the new innovations especially on use of Urine as a super fertilizer, i gonna try here on my vegetable garden in Uganda

3 years ago

That it’s a very goodway of using the urine… as a fertilizer.