I am always on the lookout for water saving techniques . It comes from having focused on this while running the metropolitan area's water system.
I, er, encountered this at MIT -- along with the handy sign that you can read while....
Back at the hospital, I inquired of our facilities folks whether we should have these in public restrooms at the hospital. A rather lengthy stream of information ensued from Mark Lutisch, our utility manager. I'll include most of it, for those of you who might be interested as you consider this in your own facilities.
Waterless urinals can save a lot of water and be fairly clean, with minimal odor. As waterless urinals don’t flush, there may be a reduction in bacteria or pathogens that are transported in aerosols to users. However, waterless urinals are not a set-and-forget plumbing fixture.
Prior to a waterless urinal retrofit project in older facilities, it is highly recommended that facilities 1) ensure that the slope of the drain line is ample, and 2) route drain lines to avoid problems such as sediment build up and 3) check drain heights are appropriate to the brand to be purchased. 4) Heavily corroded pipework should be replaced with PVC pipes. Facilities are far less likely to encounter problems with retrofit projects if these preparations are made.
A special and often-patented trap assembly that requires a special lighter-than-urine liquid must be added to the regular bathroom maintenance schedule. The trap assembly and the trap liquid must be added to the list of consumables that need to be purchased and resupplied for the life of the fixture. Maintenance staff require training in the proper care and feeding of all waterless urinals. Once the plumbers are gone, it’s up to the building staff to maintain the fixtures, and they still need daily cleaning and disinfecting, waterless or not. It may be necessary to clean urinal pipework before installing waterless urinals.
Toilets account for about 20% of BIDMC's water usage, urinals about 1%. A study by Water Management Inc. in 2007 recommended a focused fixture replacement program that zeros in on the fixtures with “the most bodies per potty”. They proposed to replace fixtures that have high per use flows and receive consistently high usage. These fixtures are generally located if common area and staff restroom facilities. Some plumbing fixtures would be excluded from the project scope based on low usage profiles. The cost was estimated at $380K with a 4.5 year payback. Because the energy budget did not have $380K for this measure, and the 4.5 year payback was not as good as other projects, toilet and urinal replacement was excluded from the water conservation project.
Instead of installing waterless urinals, Water Management Inc. recommended simply modifying the flush valves on 50 high use urinals to reduce the volume used per flush to 0.8 gallons per flush, saving about 282,000 gallons and $4K per year. Replacing the flushometers (possibly with infrared no touch sensors) is a cost effective way of reducing urinal wastewater.
In FY12 the energy plan will request funding for toilet and urinal replacement, along with a study on rainwater harvesting, greywater harvesting, and irrigation scheduling. However, we may pilot low flow toilet fixtures sooner in several high use bathrooms.
Thanks for your support,
Utility Manager, BIDMC