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Secrets of the solar-powered privy

Article by Hal Walter

Rural Life – August 1994 – Colorado Central Magazine

Most folks prefer to cook their food before they eat it. In Custer County, it soon may become fashionable to cook it afterward as well.

The county’s ban on the use of outhouses and pit toilets has put a load on many residents’ minds: “Where to go?” One solution is Wyoming; another is out to the ol’ self-contained solar toilet.

Before it got hot this year, I saw one of these “craptraptions” being installed at a camping area on a guest ranch 12 miles east of the Westcliffe-Silver Cliff metro area. Bear Basin Ranch has no flush toilets.

The headmaster for this project was Bob McConnell of the American Alpine Club. Last fall, McConnell and Earthship designer Michael Reynolds installed two of these toilets at the Himalayan Mountaineering Institute’s base camp in India.

McConnell says the solar toilets can be built with hand tools and about $200 in raw materials from local hardware stores — wood, plywood, aluminum-coated bubble foam, screen, tin, duct tape, and plexiglass. When complete, the toilets require no water, power, or expensive septic systems.

Since he is still perfecting the design, McConnell hasn’t released blueprints. However, he has a grant from the American Alpine Club to publish a book on how to build these toilets, and it should be out soon.

Once the toilet is built, it is placed in a shallow pit, with Styrofoam insulating the bottom and sides. Then the area around the toilet is backfilled with dirt.

When someone uses the toilet, the feces falls onto a sheet of quarter-inch screen. Liquid falls through the screen into a catch-pan. After sufficient dung accumulates, the toilet-seat cover is removed and the plexiglass cooker is placed over the “facility.” In India, McConnell installed two toilets side by side so that one could be open for use while the other was cooking. He’s also working on a design that allows simultaneous deposits and cooking.

On a cold, snowy day, the temperature in the toilet reached 100°F in just 15 minutes. McConnell says the toilets he installed at 14,600 feet in India routinely reach temperatures above 250°F.

The high temperature cooks the waste to ash, which then falls through the screen and is collected on a finer, removable screen below. “This ash is sterile and can just be tossed, ” says McConnell. Any liquid on the pan evaporates or is cooked.

Locally, the question is whether the county commissioners will go for the solar toilets.

“Someone ought to go to Custer County and get $2,000 in grant money and build 10 of these things,” McConnell says. “Then have a government agency test the ashes…”

“You want the gospel from the highest authority saying ‘this is a good thing,'” says McConnell, “And my test of a good thing is if it sterilizes human waste.”

And if it doesn’t?

“It should meet the standards,” says McConnell. “but if worst comes to worst, all you’ve got is a pan of …”

Hal Walter has indoor plumbing in Custer County.