Note from Matt & Betsy: Today’s subject may be a little “out there” or offensive to some, but we really think the topic of composting toilets is worth knowing something about. Yes, we’re doing a little potty talk today. We suggest you don’t read this while eating. Enjoy Deb’s great article!
In my preparation to live off-grid, I’ve come up against some interesting challenges. From heating the house to growing food to…well…using the “facilities.”
Although we don’t like to talk about it, everyone uses the restroom – several times a day in fact. And though modern toilets use less water, they still use a lot of water – and electricity (if you have a well pump).
What if you could avoid the waste of hundreds of gallons of water a week and thousands of kilowatts of electricity a year? This sort of thing is possible if using a composting toilet!
Why Would You Want a Composting Toilet?
If your present bathroom is working fine, why would you want to change it? You may not want to, but it may become necessary. Or, if you’re living in a situation that has limited water and electric, you may want to install one. The advantages are great:
- composting toilets don’t require as much electricity or water, some none at all
- being they use little or no water, they do not add to sewage or storm water drains
- the consumer’s water bill will be much less
- they can be used in places where conventional systems can’t
- it eliminates the need for transportation of wastes
- composted waste can be used in gardening and lawn care
- the cost can be very little (or even nothing) depending on how elaborate you make your plans
I lived in a log cabin (fully renovated and modernized inside) that had no water connections upstairs where I had my bedroom. I came up with the idea of a composting toilet after hiking on the Appalachian Trail where I had seen them. It was a simple concept. Something like an outhouse, the wastes went into a large bucket and were covered by the user with mulch. I took this idea and ran with it.
Assembling the Composting Toilet
Actually, I cheated, I didn’t build mine. I took a bedside toilet chair (purchased from a thrift store for $3.00!) and put a 5 gallon bucket underneath it to collect waste. I then added about 6 inches of mulch to the bottom of the bucket and used the composting toilet a few times over the next week. (I got mulch for free from a community site where the mulch produced in the area is dumped and made available to gardeners. So this didn’t cost me a dime either, except to go and get it.)
As you can imagine, and odor developed in the toilet and I tossed the first part out into my hugelkultur and covered it with soil. Only liquid waste remained at this time, so there was plenty of time for the pathogens to die off.
I started over with the same basic idea and added one small thing. Each day I added a few drops of pine essential oil. I tried lavender, tea tree and rosemary, but none of them worked as well as pine. This was a hit. The bucket of waste was then dumped into a compost pile that would generate enough heat to destroy pathogens. Then I discovered that urine does not contain near as many pathogens as feces and most will be gone after a week of sitting exposed to the air. So I went to the next level and dealt with the “other” part – solid wastes.
More on the Composting Toilet
I used the same system, put it together the same way, but removed solid wastes with a litter scoop (similar to those used for kitty litter) and placed it in vegetable starch-based bags (found here or in pet stores). Be sure to get the ones that say they are plant based and are biodegradable. These, once used, can be placed into an empty 5 gallon bucket. When full, the bucket can be sealed and left for a year that way. After a year, the pathogens will be destroyed and the resulting compost can be used in gardening. If you’re worried about anything lingering, such as harmful bacteria, you can relegate it to your lawn or non-food producing plants. After this time there should be no odor to deal with.
Alternately, the full bags can be placed in a “hot” compost pile, one that reaches at least 140°. This will destroy most any pathogens that might be present, including coliform, salmonella and shigella. Leave the compost for a year to work it into the rest of the yard waste.
If you’d like to learn more about the proper and effective process of DIY composting systems, check out Humanure by Joseph Jenkins. You can find it here.
As with any system, there can be downsides. Here are a few that have been brought up in discussions:
- this type of system requires more maintenance by the user and owner
- the end product can be unpleasant to deal with
- most systems can have limited capacity
- improper cleaning can lead to health concerns
- the solid wastes must be heated to 140° to destroy pathogens
- this type of system can produce odors
- some municipalities do not allow this type of system
- there may be issues with disposing of waste near a waterway
Some commercial systems have urine diverters so the liquid can be harvested separately. If you do this and want to use it after a week or so, use it at a 10:1 ratio – that is, 10 parts water to 1 part urine. And be sure to only water the ground and not the plants as urine can contain dissolved salts that may harm foliage.
All in all, composting toilets can be a good solution when conventional methods are not available or desirable, or in my case, when there will be limited resources to run such things as toilets.
Want to try it but don’t want to make your own?
If you think composting toilets are a great idea, but want something a little more refined and well-designed, you can always find commercially made composting toilets. They are made for houses, boats, RVs, cabins, and other spaces. Check out a great design here that has a urine diverter as mentioned earlier. (You’ll notice these are very expensive to purchase, so it’s wise to consider the DIY route for this project.)
Have you used/made a composting toilet? How did it work?