The key to the waterfree Urinal system is a biodegradable cartridge at the base that acts as a funnel.  A liquid sealant closes in the cartridge as waste passes through and eliminates odor, which is created only when there is a chemical reaction between urine and water.

Smelling Like a Rose - Waterfree Urinals Reduce Odors While Conserving Water
The Rose Bowl will soon be packed with fans hoping to cheer top-ranked USC and the University of Michigan on to victory while also reducing odors and conserving water.

That's because all of the trough-type urinals in the men's restrooms at the Rose Bowl have been replaced by 259 Waterfree Urinals.  With 91,000 fans expected for the game on New Year's Day, the water savings will surpass 130,000 gallons for this one event. When combined with the savings from UCLA's home football games, concerts, Fourth of July celebrations and other events, the total water conserved in a year is more than 1,000,000 gallons--a substantial amount for a region where the fresh water supply is struggling to keep up with demand.

Waterfree urinals look like standard urinal fixtures but have no incoming water line and don't use any water. Instead, a replaceable, biodegradable cartridge at the base of the urinal acts as a funnel. Liquid waste passes through the cartridge, penetrating through a lighter-than-water liquid sealant that closes after the urine has passed. Odors are eliminated, since urine is trapped below the sealant and the chemical reaction between water and urine that creates the odor associated with flush urinals is eliminated.

Independent studies in the U.S. and Germany have shown that Waterfree Urinals are also more sanitary than traditional flush urinals. Because water is eliminated, there is no breeding ground for bacteria. And, since Waterfree Urinals are touch free, germs are not spread as easily.

Waterfree Urinals have also been installed in Miami's Pro Player stadium -- site of the 2004 Orange Bowl. With 70,000-plus fans expected to be in attendance for the contest between Miami and Florida State, the total water savings from these two bowl games will be more than 237,000 gallons.

Waterfree Urinals have been installed in many locations around the world since the mid-1990s. Other well-known installations include the San Diego Zoo, London's Heathrow Airport, and the University of North Carolina.