Composting Toilets

An eco-friendly alternative, but are they ready for the mainstream?

Did you know that every time you flush a toilet you use up more water than most people in the developing world have to use all day? For those who are conscious of such things, a composting toilet just makes sense. It uses far less water than even a low-flow toilet and can convert your waste into a natural (and powerful) fertilizer for decorative plants around the yard.

But for people who are married to the “flush and forget about it” advantages of a standard toilet, the idea of composting their own waste (referred to as humanure) makes them more than a little squeamish. This is for good reason, as human feces contain strong bacteria and other pathogens that can cause serious disease. Plus, the stuff is just plain stinky. But if you’ve got the right equipment and follow some strict but simple guidelines, the process of using a composting toilet should be both perfectly safe and virtually odorless.

How it all works

When making a commitment to a composting toilet, the object of the game is to turn your excrement into something called “humus”. No, we don’t mean the stuff you spread on a pita. It’s a stable soil-like material that takes up only about 10 to 30 per cent of the human waste from which it was derived and can be used in your plants and gardens. There are generally two types of composting toilets that allow you to accomplish this: those that are fully contained within the toilet unit itself and those that require a separate compost dump. The former is typical of smaller toilets used for visits to the cottage or on camping trips; the latter is more for a permanent residence.

There are some major components to any composting toilet that require a hefty investment up front. These include:

• A composting reactor;
• A ventilation system that provides a steady supply of oxygen to the waste to facilitate decomposition;
• An exhaust system to remove carbon dioxide, odors, water vapour and other bi-products of the decomposition.

If your composting toilet is set up properly, it should produce humus that is reasonably dry, relatively odorless and safe to handle. It does take a while: the full decomposition process could last anywhere from three months to several years depending on a number of factors, including temperature, rotation frequency and moisture levels.

Unfortunately, in much of the United States and other parts of the world, once you compost your waste you’re not actually allowed to use it. Many jurisdictions require humus to be buried or removed by a licensed seepage hauler. But regulations and standards for full decomposition are being improved to allow composters to use their humus around the house and yard. It’s best to check with your Department of Health to see what rules apply in your area.

Who sells composting toilets?

There are a number of reputable manufacturers of composing toilets, including Sun-Mar, Biolet and Nature Loo. Most major brands brag about the ease and safety of using their toilets, but here are a few simple things to keep in mind when you go shopping:

• The unit you purchase should absolutely adhere to best sanitation practices. That means you should never be exposed to unprocessed human waste any more than you would be with a standard toilet.
• Organisms that carry disease (such as flies) should never have access to unprocessed waste. This applies both to the self-contained composting toilets and the ones that require a secondary composting tank.
• Your toilet should produce humus that is inoffensive. That means no odors. If your eyes start to water, send it back!
• Your unit should adhere to state or federal certification guidelines. If you are buying a composting toilet in the United States, the common standard is NSF® Standard.