Sustainability The Waterless Toilet: 5 Options for Greater Sanitation with Little or No Water

Published on August 25th, 2011 | by Jeff McIntire-Strasburg

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The Waterless Toilet: 5 Options for Greater Sanitation with Little or No Water


This post is sustainablog’s contribution to Important Media’s celebration of World Water Week.

Like many of my peers, I was pretty excited when the Gates Foundation announced its “Reinventing the Toilet” initiative (which our sister site Ecopreneurist covered very thoroughly). As the Foundation’s video introduction (above) notes, the lack of sanitary means to handle human wastes sickens or kills many people in the developing world.

We’ve got the sanitation part down here in the US… but it comes at the expense of our water resources: even with the rise of low-flow and dual flush technologies, toilets are still the biggest water hogs in our houses. The EPA notes that the toilet alone can be responsible for up to 27% of our home’s water use.

I don’t know how that compares to some other big users of water out there, such as agriculture and energy production, but it’s pretty clear there’s room for improvement on this front… and we don’t have to sacrifice sanitation to make those improvements. In addition to the water that goes down the drain (and, again, following with the Gates Foundation’s objectives), we’re also flushing a lot of useful material… yep, there’s energy and useful chemicals in those unmentionables.

So, in the spirit of recognizing the flush toilet as a tremendous advance for its time, but one that’s prety limited in this day and age, I’d like to take a look at a number of waterless toilet technologies that already exist… and that also put our wastes to good use.

Humanure

This is about as basic as it gets: using a bucket for a toilet (and, yes, I’ve done this… it’s pretty standard up at Dancing Rabbit). But that bucket is filled with sawdust (and you keep a bit more nearby for “flushing”), and when it’s full, you can add it to a compost pile or bin. Eventually, you’ve got garden fertilizer… which, yes, you can even use on edible plants.

Despite what Joseph Jenkins, the author of the Humanure Handbook, says, it does smell… not nearly as badly as you might think, but more than we pampered Americans want. But it’s also the cheapest and easiest way to completely cut the water use of a flush toilet, and “close the loop” on human waste. Time did a good overview a couple of years ago.

The Composting Toilet

A step up from humanure, the self-contained composting toilet also turns wastes into useful food for soil… but doesn’t require regular hauling of a bucket outside. The phrase itself is a bit of a catch-all: their are various designs, and a number of different features that manufacturers may offer (including some that use a little water). All use aerobic decomposition to break down wastes (as well as toilet paper), and can hold and process wastes for months or even years.

Downsides: first, they’re pricey. Second, you’ll still have some smell. And, finally, they do require more regular maintenance than they typical flush toilet. The EPA has a useful fact sheet on composting toilets.

Incinerating toilets

While this option is also water-free, and doesn’t have the smell issues associated with it, it’s got some definite disadvantages from a sustainability perspective. Obviously, to incinerate something, you need fuel: these toilets use electricity or gas to burn up the waste.  Secondly, there’s no real closed loop benefit: while its easy and safe to dispose of the ashes, the burning of the waste takes the nutrients with it. The EPA also has a fact sheet on incinerating toilets.

The Methane Harvesting Toilet

This is a new one that I came across while searching for green tech finds back in May. The Loowatt (currently being tested in London) could be called a composting toilet, but it uses anaerobic digestion to harvest methane from human wastes that can then be burned like natural gas. Only disadvantage I can see right now is the need to empty the storage canister more frequently than a conventional composting toilet.

The Solar-Powered, Hydrogen Producing Toilet

OK, this one’s not waterless… but it does make much better use of water than the traditional toilet, and also produces energy. The researchers developing it at Cal Tech are among initial grant recipients from the Gates Foundation program, and it’s pretty easy to see why. Using solar power, the unit not only cleans the waste water “up to the same level as would come out of a treatment plant,” (so it’s reusable) but also produces hydrogen from the waste itself.

There’s a lot going on in this space, even before the Gateses started offering money… if you know of something I missed, either in use or in development, show me up in the comments.

Other World Water Week Posts from Important Media Sites

Photo credit: cod_gabriel at Flickr under a Creative Commons license



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About the Author

Jeff McIntire-Strasburg is the founder and editor of sustainablog. You can keep up with all of his writing at Facebook, and at



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