We got started on waterless urinal development through talking to Carol McCreary of PHLUSH at Recode’s Greywater celebration and revised our plans through discussions with Carol, Jeff, Barbara, and everyone in PHLUSH.

I gave a talk on this subject over at Research Club Sunday, 4/10 at the Tribute Gallery. Special thanks to Tribute director Brian Wilson for his hospitality when we showed up unannounced with a home-made urinal.

From our research talking to portable toilet companies, 9 out of 10 visits to public restrooms are for urination only.   We think there is a great need for gender-neutral urinals designed for easy and comfortable use, and a cultural shift towards making urinals acceptable for women.  Urine is a much easier product to handle and clean of pathogens than feces, or urine and feces together.
Urinals can solve two problems: gender equality in bathroom access, and the often disgusting toilet seats that women have to sit down on in portable toilets.

Make your own

We have designed a very simple $8 gender-neutral urinal for our house.  The urinal is nice because we used to have a “let it mellow” policy for our toilet, but that system carries an odor.  With our simple urinal we have no smell in the bathroom, but it does need to be emptied every 3-7 days (four people use it, holds about 40 “events” + a small wash of water).  Our inspirations were the Little John, Lady “J”, Urifemme, and the ubiquity of 5-gallon buckets.

Urinal Design Issues, Patterns
Our urinal uses a standard automotive funnel (NAPA part#BK8215212) that conformed fairly well to our design pattern.  The primary problems we want to mitigate are back-splash from the urinal and misses.

Amongst male urinals, I prefer “scoop” urinals.  Upright privacy urinals with walled sides have, I think, an unacceptable amount of back-splash.  They trade functionality for an infantile male desire for privacy. Design at its worst: playing to insecurity and then punishing the user with poor performance.  The scoop urinals are also similar in shape to female urinals (more info and images  here and here)- both function well because the walls of the urinal meet a stream of urine at an obtuse angle to direct rather than reflect the flow. [[[I'm not using a public urinal unless it's in a stall -Molly]]]

While our urinal presents a small target, it is a close and approachable target because it does not splash back.  For male users, a standard toilet is a 10″ x 12″ oval target roughly  18-20″ away, whereas our urinal is a 5″ circle 4-6″ away.    Although an unfamiliar configuration, it is actually an easier target.

For female use our NAPA funnel is the best pre-made funnel we could find but not the ideal shape.  A long oval with a curved top would be best (see illustration), like the Lady J with a more obtuse angle.   We’re considering vacuum forming our own, but are not yet ready to invest in the equipment and mold-making.

Right now toilet paper goes in our flush toilet.  We’re thinking that a foot-peddle-type trashcan would work best, possibly with a cover material like sawdust.

Urine Diversion: risks & mitigation
Our urinal is a collection system because we are excited about the possiblities of land application/ fertilization.  healthy adults have sterile urine  and urine contains high-value fertilizers.

Although a low risk, urine can still contain pathogens such as hepatitis A & B, CMV, JCV and BKV (flu-like viruses), albeit at low levels with a low risk of infection*.  It appears that urine retention can kill most of these pathogens through pH changes, but hepatitis is very environmentally persistent.

So we’re investigating a point-of-collection sterilization system based on UC Berkeley designs for the UV-Tube, a simple UV-C sterilizer tested in fluorescent and LED Models.  Such a system would make urine a non-pathogenic material, drastically simplifying handling and the deployment of public urinals.

Alternatively (or additionally) urine is a perfect nitrogen source for jump-starting compost, and mixtures of carbonaceous material (sawdust, paper, etc.) and urine are very fast to decompose.our research indicates that 3lbs of urine can be soaked in to 1lb of sawdust (along with some additional water)**.  High temperature composting can sterilize urine, and appropriately configured with a bio-filter, capture all nutrients.

*WHO: Urine Diversion: hygienic risks and microbial guidelines. Schönning, Caroline. Swedish Institute for Infectious Disease Control (SMI): 2001.

**statistics from Integral Urban House Book, page 214

Other great sources and design guidelines

Urine diversion components: Overview of urine diversion components such as waterless urinals, urine diversion toilets, urine storage and reuse systems. Deutsche Gesellschaft für Technische Zusammenarbeit GmbH (GTZ), Sustainable sanitation – ecosan program, December 2009.