Composting toilets offer interesting alternative

You’ve probably seen or read about the growing popularity of “tiny houses” and some of the many things they do a bit differently from conventional housing in their design and construction. One common difference is the use of a composting toilet, which doesn’t rely on water or a sewer connection.

But composting toilets aren’t just for tiny houses. They can offer a great alternative for vacation cabins, shops and warehouses, off-grid homes, and even basement and below-grade bathrooms where conventional sewer hookups could be expensive or even impossible.

A composting toilet is fully self-contained. The typical unit requires no water inlet, no connection to a sewer or septic tank, and no chemicals. An electrical connection is required, which can be either 110 volts or 12 volts, depending on the unit, which means composting toilets also have the potential to be used in an RV or operated off solar power. An outside vent also is required.

How they work

Different manufacturers utilize different designs, so there are differences in exactly how they operate. But here’s the basic principle.

Liquid waste that goes into the toilet is diverted into a separate area, typically into a small holding tank that is emptied every few days; some types have a drain that allows the liquid to be routed to the outside and into a drain field similar to a septic system. Other types of composting toilets evaporate the liquid waste so there’s no removal or disposal at all.

As far as the solid waste is concerned, before first using the toilet, a small quantity of peat moss or another natural absorbent material such as sawdust is placed in a tray in the toilet. An agitator handle on the side of the toilet is turned after each use, which mixes the waste with the absorbent to allow for a natural composting action.

A fan or heater often is used to speed the drying and composting action. The resulting composted absorbent-solid waste mixture ends up like a dry, odorless dirt, which can be recycled outdoors.

The final component of the composting toilet is a vent and fan. The vent goes to the outside of the building or vehicle, and the fan removes odors through the vent. In actual operation, users of properly installed and operated composting toilets report no odors.

Two types of units

There are two basic types of composting toilets, self-contained and high-capacity. With self-contained units, the composting action occurs within the toilet itself, and the waste is also stored there until it’s ready for disposal. These units are best suited for small or mobile spaces, or for lighter use.

For heavier use by more people, or in larger, permanent structures that won’t be moved, there are high-capacity composting toilets. These units operate the same way, but the composting and storage takes place in a remote tank that’s away from the toilet itself, allowing for greater capacity and a longer interval between emptying.

Pros and cons

A composting toilet is obviously not for everyone. On the positive side, these units are beneficial to the environment, since they utilize little or no water. They also reduce the impact on private and community waste disposal systems.

Depending on the toilet and state laws, if you’re using a composting toilet in a building with a conventional septic system, you may be able to reduce the size of the disposal field, which will save on installation costs. Some composting toilets can also be used to compost kitchen waste.

On the down side, there’s obviously more work and more maintenance involved with a composting toilet. And if the toilet is installed or operated incorrectly, or if you don’t keep up on the maintenance, you may end up with odors, and removing and disposing of the composed waste may end up being a less-than-pleasant task.

Finally, there’s the psychological component. Even when everything’s working perfectly, not everyone’s going to be comfortable with the concept of using or operating a composting toilet.

Compare models

If you’re considering a composting toilet, it’s important to do some comparison shopping. You need to understand how different models operate, what it takes to install them, and what it takes to maintain them.

You’ll also want to check with your local building department to see what rules apply to composting toilets, including both installation and disposal of the dry, composted waste.

Composting toilets are available through a variety of retailers, including home centers and suppliers of plumbing fixtures, as well as through online retailers.

Costs range from around $950 and up for self-contained units to $1,900 and up for highcapacity units.