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Environment: The Waterless John

2 minute read
TIME

Every time a toilet is flushed, about five gallons of water sweep a pint of human waste into the sewage system. This prodigious waste of good water has long upset dedicated environmentalists. Indeed, after the invention of a pollution-free car, a better toilet system has been their No. 1 priority.

A new process quaintly called Aqua Sans may be the answer. It was created by the Chrysler Corp. in response to a request by the U.S. Navy for an improved way to handle wastes aboard ships. “We didn’t want anything to go overboard,” says Ralph Loomis, project manager of Chrysler’s waste treatment systems in Michoud, La. “We decided we had to have a closed-loop system.”

Easier said than done. The biggest hurdle, Loomis says, was to find a reusable flushing substance: “We needed an oil-like fluid that was lighter than water, that would be readily separable from water and that had a very low solubility for most components in human waste.” The perfect product turned out to be very like one that was in the bathroom cabinet all along: mineral oil.

When the waterless John is flushed, this specially refined mineral oil and wastes go into a separator tank. There, urine and solids sink to the bottom, then are sent to a holding tank, where they are eventually burned in an almost pollution-free, 1200° F. incinerator that leaves a residue of sterile ash. The oil itself is filtered, chlorinated and returned odorless to the toilet tank to be used again. And again. Over a year, just 5% of the mineral oil is lost in the process.

Aqua Sans systems have been adapted to existing facilities in Mount Rushmore’s visitor center, a New York tugboat and a naval barracks at Annapolis, Md. They work well. But right now Aqua Sans is too expensive to be widely used. Each flush costs .8¢ (v. .035¢ for a conventional toilet). Still, it fills a definite need in places with plenty of business but scant water supplies: for example, in desert gas stations or mountaintop rest rooms, and, of course, on ships.

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