At July’s Lunch & Learn webinar, members of the North East Biosolids & Residuals Association (NEBRA) got to learn about the exciting work and ongoing research into Urine Diversion (UD) and its conversion to farm fertilizer by the Rich Earth Institute (REI).  With a research center and “urine depot” in Brattleboro, Vermont, REI’s vision is “A world with clean water and fertile soil achieved by reclaiming the nutrients from our bodies as elements in a life sustaining cycle.”

Did you know that urine contains most of the nutrients and half the pharmaceuticals in domestic wastewater although it is only a tiny percentage of the total wastewater volume?  That was just some of the information gleaned from the presentation by REI Research Director Abe Noe-Hays.  REI continues to research urine diversion collection and treatment innovations and refine its programs. 

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REI developed its Urine Nutrient Reclamation Program back in 2012 which was the first community-scale program of its kind in the United States.  REI used a seed grant of $1,000 to get going and the program has since grown from 60 part time “donors” and 600 gallons of urine collected to 180 full-time (and very committed) donors and 10,000 gallons or urine annually to turn into fertilizer for hay fields.  One acre of hay can use 1,000 gallons of product (50 pounds of nitrogen) per growth cycle. 

As Noe-Hays explained it, Urine Diversion consists of four steps: collection, transport, treatment, and application.  For collection, there are three basic methods including:

1.     A portable system using a 5-gallon collection container that you drop off at a community UD collection depot;

2.     Plumbed fixtures, namely urine diverting toilets of which there are several commercially-available designs;

3.     Building scale systems – very economical for new construction as opposed to retrofitting existing buildings.

For all three methods, REI provides pump out services and transportation to its treatment facility. 

REI has been continually experimenting and innovating, especially with respect to reducing energy used during the urine treatment process.  Funding has come from various sources including the U.S. Environmental Protection Agency, the National Science Foundation, the U.S. Department of Agriculture, the Water Research Foundation and even the Long Island Sound Study.  REI’s basic process involves urease inhibition (an acidic pretreatment step that prevents ammonia formation) followed by reverse osmosis to recover the nutrients.  REI is experimenting with a new process called “Freeze Concentration” to replace reverse osmosis.  Freezing the urine creates ice crystals that are pure water with the remaining “melt water” being high in nutrients making them easier to recover.  The freeze concentration process achieves much higher concentrations and reduces fouling of the system but uses more energy which REI is addressing by using the latent heat from the process itself. 

REI has collaborated with the University of Michigan where they have installed a pilot freeze concentration system connected to dedicated urinals at one of the campus buildings.  That process includes an acidification step (vinegar added at source) followed by freeze concentration and distillation.  REI has also added a final step of charcoal filtration for additional removal of contaminants such as pharmaceuticals.  REI is involved in a six-year study with the University of Michigan and the University at Buffalo on the fate of pharmaceuticals in the fertilizer used on crops.   

Biosolids has come into play in the cutting-edge research being led by Noe-Hays into the synergies of biochar and urine.  REI has found that biochar (especially from biosolids) binds and stabilizes the ammonia in urine.  And the urine “charges” the biochar with nutrients.  Research into the biochar/urine connection continues. 

REI has developed a Urine Diversion Guide (https://richearthinstitute.org/urine-diversion-guide/) to assist other communities in starting up similar programs.  REI is also advocating for more wastewater infrastructure funding for alternative collection and treatment systems like its urine diversion program in Brattleboro.