Hi Abe

This is great news that you are working on revising plumbing codes for urine collection systems. Revised codes will be a huge support for these new sanitation concepts.

At Eawag, we installed our first urine diverstion systems in 1997. The first toilets were only installed for experiments, but since 2006 we have a full-scale urine-diverting system (NoMix) installed in our headquarters Forum Chriesbach (www.forumchriesbach.eawag.ch/). From the beginning an engineering company was hired to monitor the system and to suggest improvements. Some preliminary results have been published in Swiss journal (unfortunately in German only):

Goosse, P., Steiner, M., Neuenschwander, W., Udert, K.M. (2009) NoMix-Toilettensystem. Erste Monitoringergebnisse im Forum Chriesbach. Gas Wasser Abwasser 2009(7), 567-574.

The following article contains some guidelines for the installation of NoMix systems:

Lienert, J. and Larsen, T.A. (2007) Pilot projects in bathrooms: a new challenge for wastewater professionals. Water Practice & Technology 2(3).

You might also want to get in contact with the engineering company, which does the monitoring of our system and I am happy to provide you with more information or to show you our system, if you get a chance to come to Zurich.

Hi Abe,

you can also look into the Technology Review of UDDTs with some updated information on urine plumbing www.susana.org/lang-en/library?view=ccbktypeitem&type=2&id=874.

All the best,
Christian

Hi Abe,

We installed double chamber urine diverting dry toilets, with squatting pans with 32 individual households in peri-urban areas of Herat City in Afghanistan. The urine pipe was connected from the pan to a 20L urine collection container, with 4 percent slope. Originally we used 1.5 inch (38 mm) pipes. And the maintenance was to wash the pipe through with water every two weeks (when they empty the urine container), and if needed cleaning materials. Half of the households follow this procedure of washing out with water and have no problems since 3 years. The other half didn't follow these instructions and they had problems with blockages within a few months. Blockages also occurred due to other materials getting into the pipe. For these households we changed the pipes to 2-inch pipes (50 mm) and haven't had problems for over a year (and they are not washing out their pipes.)

All the best

Nadira
GIZ Afghanistan

P.S.
This is what the toilet looks like:

Household UDDT by Sustainable sanitation , on Flickr

More of my photos in the Afghanistan collection of the SuSanA flickr database:
www.flickr.com/photos/gtzecosan/collections/72157609450245646/

Hello, Abe

Ecological Engineering Group installed several waterless and low-water urine-diverting toilets in various locations. One was in a school (in Massachusetts), where there was clogging when the plumbing was not installed to specification. It was corrected and served well with no clogging for 5 more years. Slopes were constrained because the urine drained to a subsurface system at about the same level of the basement.

Remember the variables other than sloping of pipe:
--Amount of rinse water
--Source of water (groundwater versus surface water)
--Volume and frequency of urine drained
--Additives used to prevent clogging
--Pipe interior and pipe size

This issue is also informed by guidelines for and experience of plumbing for waterless urinals.

Carol Steinfeld
Ecowaters
Ecovita
Author, Liquid Gold

Hi, Everyone. I am part of a team in the United States that is developing proposed revisions to plumbing codes that will include urine diverting dry toilets and associated plumbing and storage tanks. I am trying to determine what the best practices are for plumbing dry toilets to urine tanks, and I am hoping that participants of this forum could share their knowledge on this matter.

The main issue we are concerned with is clogging of the pipes due to deposits. A number of resources available online suggest pipe sizes and slopes, but one publication is the most comprehensive I have found so far: Muench and Winker (2011) -http://susana.org/lang-en/library?view=ccbktypeitem&type=2&id=875
Technology review of urine diversion components.

This reference states that a 1% slope is sufficient for multi-toilet systems, while 4% slope is needed for single-toilet systems. Also that 50 mm is the smallest acceptable pipe size for multi-toilet systems, while 15 mm can be used for a single toilet.

Does anyone on the forum have long-term experience with urine diversion plumbing installed to these specifications? If so, have you experienced any problems with clogging? Do your toilets flush the urine with water? And what, if any, regular drain-cleaning maintenance do you do?

What pipe sizes have you used in the past, and with what results? What is the steepest pipe segment anyone has experienced clogging in?

Thanks in advance,
Abe Noe-Hays

Research Director
Rich Earth Institute
44 Fuller Drive
Brattleboro, VT 05346
This email address is being protected from spambots. You need JavaScript enabled to view it.
www.RichEarthInstitute.org