Water-free Urinals: An Excerpt from Jerry Yudelson’s “Green Building A to Z”
Urinals waste more than 150 billion gallons of fresh water per year, equivalent to the water use of 1,500,000 homes, at an average use of 300 gallons per day per home.
Urinals waste more than 150 billion gallons of fresh water per year, equivalent to the water use of 1,500,000 homes, at an average use of 300 gallons per day per home.157 The average urinal installed since 1992 uses 1 gallon per flush, which is the code requirement, based on the 1992 federal Energy Policy Act. (Overall, the average might be closer to 2 gallons per flush for all urinals now installed.) Think of more than 78 million men at work,158 making an average of three flushes per day, five days a week, most of them older urinals using 2 to 3 gallons per flush, just to flush away a liquid that’s sterile and more than 99% water.
The design of water-free urinals includes an oil seal below the drain, which prevents sewer gases from rising up (one of the purposes of the flush and the drain) into a bathroom. The seal has to be changed periodically. According to one manufacturer:
This pleasant-smelling sealant liquid trap provides an airtight barrier between urine and the restroom to prevent odors from escaping the drain, but allows urine to pass through because it is lighter than water. Urine immediately penetrates the sealant liquid and flows to the drain. Uric sediment is collected by the cartridge, leaving an odor-free environment, clean pipes and absolutely no water waste.159
Basically, water-free urinals work just fine in situations where there is a large, often anonymous population of users, such as office buildings, restaurants, airports, schools, stadiums and theaters. With proper design and installation, routine maintenance (including quarterly treatment-cartridge replacements) and a little signage to tell users what’s going on, water-free urinals work just fine, reducing overall water consumption in buildings by up to 40,000 gallons per year per urinal.
Water-free urinals are used in such places as the Jackie Gleason Theater in Miami Beach; the Evergreen State College in Olympia, Washington; the Harold Washington Social Security Center in Chicago; the twin Petronas Towers in Kuala Lumpur, Malaysia; and the Jimmy Carter Presidential Library, in Atlanta, Georgia. Over the long run, widespread adoption of water-free urinals will also help reduce future infrastructure development costs by reducing water demand and sewage generation. From the standpoint of economics, water-free urinals, either in new buildings or in renovations, pay for themselves in water savings in a relatively short period of time.
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Posted by on 01/15/2008 at 05:45 PM
