Solar Composting Toilet System

An ecological design for a waterless, compost toilet at the Ecovillage.


| January/February 1984



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Solar-heated air enters the composting toilet system cabinet via a 3-inch duct, and a 12-inch vent pipe assures rapid airflow for proper compost drying and odor elimination.


PHOTO: MOTHER EARTH NEWS STAFF

It's pretty hard to deny that the common flush toilet is the easiest, most "euphemistic" apparatus yet invented for disposing of human waste. Trouble is, it's also the most wasteful: Just flip that chrome lever and—whoosh!—five gallons of potable water take the plunge, to carry away a few ounces of solid or (even more wasteful) liquid effluvium.

So what's the best alternative available to the growing number of environmentally minded folk who are hunting for a convenient, economical way to dispose of human waste without creating a water-squandering situation? That's the question Eco-Village staffer Jay Herndon asked nearly a year ago when he decided to assign himself to Project Privy. His mission: to build a good, ecological commode.

No-Flush Options

By examining and weighing the options—water-saver toilets, nonrecycling waterless commodes and waterless waste recyclers (better known as composters )—Jay saw almost immediately that the all-around most sensible choice would be a composting toilet. In addition to disposing of sewage without the use of any water, this improved outhouse system offers the bonus of organic fertilizer.

Once Herndon had decided on waterless waste recyclers, his next step was to look around at what composting toilets others had come up with, both commercially and on a homebuilt basis. He soon learned that the U.S. Forest Service in his neck of the woods was using a composter. It was a "stair-step" model, the type that requires a large (4' X 4' X 12') subfloor space, and needs close to a two-year accumulation period for a batch of composted material to work its way down to the bottom, where it can then be removed. A good effort on the part of the forest service, but not what he was looking for.

A second model, called a "two batcher," had been tried by several local do-it-yourselfers, but it wasn't all Jay hoped for either: It required too frequent shoveling of the heap from one composting bin to another. Moreover, both of the units he inspected evidenced some degree of insect infestation and, you guessed it, odor.

The next step in the search for the perfect waterless toilet was to scout out the commercial offerings. Here, the main problem was price: The average cost of commercial composters is in excess of a $1,000, and such units almost always require an external source of power to provide venting and drying heat.

chris66
1/11/2015 8:04:29 PM

How do these work in colder climates? Thanks Chris


kennan
8/3/2009 10:54:03 AM

My family and I have been using this MotherEarth design for over two decades....only problem: family of six, ironically, doesn't produce that much compost, but you can imagine how many thousands of gallons of water have been conserved!






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