Making it rain

Researchers in Vermont recycle urine for use as fertilizer
Courtesy of Kim Nace

Recycled urine passes initial test for use as a fertilizer

It’s a practice that was used for thousands of years, but with the development of sewage systems and chemical fertilizer, the practice of recycling urine and using it as fertilizer went by the way side. Recently, this old practice gained new momentum in the U.S. when the first legally authorized and publicly documented communityscale urine reuse project, conducted by Rich Earth Institute in Vermont found human urine has a use as a viable fertilizer.

“Our population needs to close the nutrient cycle, and can do it in the most expedient way possible by extracting all the nutrients from our human waste,” says Kim Nace, founder of Rich Earth Institute. “I always put waste in quotations because really it’s a resource; it’s just a resource in the wrong place. It’s only pollution because we’ve got it in the wrong place.”

The scientifically documented success of the crops treated with recycled urine by the Rich Earth Institute, and the additional funding awarded to them for their success in the form of a U.S. Department of Agriculture grant, shows an interest in this practice. Using urine as a fertilizer instead of flushing it down the toilet could save 4,000 gallons of water per person a year, according to the Rich Earth Institute. The battle, according to Nace, is getting people over the “ick factor” of having to collect their own urine, and getting the research together that would prove that recycled urine is safe to use.

“The proof that this concept works, we don’t have any doubts on that any more because of our initial results,” says Nace. “We know that urine is a fertilizer that is equally as strong as chemical fertilizer. In those terms, we are very confident in moving forward.” For the Rich Earth Institute’s initial field test trials, started in 2012, they grew strips of animal crops such as hay. They reached out to the community in order to get enough urine for the project. After collecting the urine, researchers used two different methods to sterilize the urine before use, either by heating the urine to 70 degrees Celsius in small batches using a solar heater, or using long-term storage methods, such as researchers from the Swedish University of Agricultural Sciences have done during their urine recycling research, which spans almost 20 years. This long-term storage method relies on the fact that stored urine becomes very alkaline, allowing for the acidity over time to destroy any pathogens that may have been present.

“I really trust that information quite a bit. I think [the researchers of the Swedish University of Agricultural Sciences] have a lot of integrity in the way they have done their work, and they’ve done it a lot longer than we have in the U.S.,” says Nace. “Their information has served as a foundation in our work, and I think it’s really excellent that there is a foundation that we can keep building upon.”

With the exposure of this practice and Rich Earth Institute’s research, in articles, such as “Is ‘Peecycling’ the Next Wave in Sustainable Living?,” on National Geographic’s website, Nace says, they have received increasing interest in the program. At this rate of public exposure, she says she believes the “ick factor” will be overcome quite quickly. The real issue, she says, is addressing the fact that pathogens and pharmaceuticals can be present in human urine. The Environmental Protection Agency researched some of the Rich Earth Institute’s initial test site soils and plant matter, but never gave them any conclusive data. She says this information is necessary for the regulatory process when it comes to the installment of urine-diverting systems in homes and broadening the acceptance of this practice.

Representatives of the Water Quality Control Division for the Colorado Department of Public Health and Environment (CDPHE) agree with her that adequate research material would need to be provided for the investigation of urine-diverting systems to get underway. Dick Parachini, clean water program director of the Water Quality Control Division for the CDPHE, says there really hasn’t been a push from the public to research this process with the state in order to develop the regulations necessary for Colorado citizens to be permitted to use urine-diverting systems on their property.

But really a person can just start this practice simply by collecting their urine in a bucket or a bottle by diluting the urine to eight parts water, one part urine, according to Carol Steinfeld, the author of Liquid Gold: The Lore and Logic of Using Urine to Grow Plants. Steinfeld is also the founder of Ecovita, a company that sells urine-diverting toilets. She says she hasn’t heard of any cities expressing concern over this small amount of urine being used as fertilizer on people’s own property.

“Essentially, in the wastewater treatment plants, we have a lot of nitrogen going in and the easiest to pin point is urine; human urine makes up most of it,” Steinfeld says. “Purchasing fertilizers to put on our land on our farms, more and more, we are going to need to close that loop in order to save money, to save energy.”

Steinfeld says there are a few reasons why people are interested in urine diversion in the states: the sustainability of recycling nutrients, water conservation and using the nitrogen before it goes to wastewater treatment plants, where expelled processed wastewater can cause hazardous blooms in oceans and rivers. For example, Boulder County’s treated wastewater is dumped into Boulder Creek.

Lauren Allen, a representative for Gray Water Action, a company that provides workshops in implementing sustainable technology, such as urine diverting toilets, says people may choose to divert urine if they are having odor and composting issues with their composting toilets. This is the case at the Central Rocky Mountain Permaculture Institute (CRMPI) in Basalt, Colo., says founder Jerome Osentowski. They urinate on their forest gardens when their composting toilet, “sunny John,” has urine content too high to function properly. He says that salt levels can be a problem with certain plants, such as avocadoes, so avoiding urinating on those kinds of sensitive plants is best.

One of the more significant reasons people are interested in this practice, according to Steinfeld, is that if it were applied on a wider scale, it could decrease the carbon footprint produced by wastewater treatment plants. The majority of energy used at the plants goes toward extracting and diffusing the nitrogen and phosphates that are present in human urine.

“Treatment plants are going to have to continue to meet standards of nitrogen and phosphorus filtering, and municipalities don’t have the funding and taxes to put into these enormous facilities. Some of the figures I’ve received about doing a quality denitrification all around the country are just so expensive,” says Nace.