Composting toilets

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rules : Building composting toilets : sewage

Composting Toilets We have six composting toilets and two Pee gardens

Composting toilets convert human waste into compost – usable soil. Wikipedia has a great article on the history of composting toilets and how they work. For our composting toilets, each toilet has two chambers. One is used for a year, then we switch to using the other side. The side which is not in use has intense microbial activity with the temperature rising to 77 C (170 F) as the material composts. Composting worms can be added for vermicomposting and we also have dung beetles in the chamber. After a year, that side is ready to be emptied of its soil, which can be used on gardens. We use the compost on non-food gardens, but scientific data suggests the soil is perfectly safe for food gardens as well.

Before it’s annual use cycle, the chamber is prepared with carbon-high grasses which grow invasively in the forest. After every use a handful of oak leaves or sawdust is tossed into the toilet to balance the carbon and nitrogen and aid in the composting activity and in eliminating odors. Ventilation tubes also eliminate odors.

The major advantage of composting toilets is that useful water is not combined with human waste, which then needs to be sent to a centralized sewage treatment plant to be processed. Approximately 40% of normal household water is used just for flushing toilet. We use none.

Our design is very simple because we have both space and time. For us, it is not necessary to have expensive composting toilets with fans and electricity.

If you can't build a composting toilet due to some regulations, you may still be able to make a pee garden! What is a pee garden or pee patch?, and they are a good complementary system to a composting toilet as well.

to do

  • Write up list of all elements of a simple composting toilet.
  • Video evaluating each toilet. At end record the commonalities most share.
  • Need to make or get a foot release water thing for hand washing.
  • Quora: Which bacteria break down human waste into soil?
  • Quora: How do various diseases respond to the composting of human waste?

List of all toilets

  1. First one was built next to the studio at the [[lodge]. We need to build a larger composting toilet and pee garden here.
  2. Casita Spacious with a sit down pee garden seat. Need to build a standing
  3. Near Boogg,
  4. At the View cabana. There is a pee garden used from the upstairs porch. Need to a public pee garden.
  5. Bliss
  6. A the Cosmic and Truth cabanas.
  7. We should also build one on the Farside at the Outpost.

Questions from Godfrey McDonnell

  • What is the minimum size for a pooping outhouse for five dogs and one regular male user?
    • Brian says: I tend to like to build the chambers too big so they don't have to be emptied as much. My chambers are about 4x4x4 feet which is enough to handle at least 5 human users. Some testing would be needed to determine ideal sizes, but in general I overbuild.
  • How much sawdust is required to maintain it?
    • Brian Says: A scoop to cover the new deposit should be added after each use. About a cup or so. I have experimented with not adding anything and some small flying bugs were there after a few weeks. Such problems would depend on the climate. I get my sawdust for free in large bags at the sawmill and keep a 5 gallon bucket full with a scoop next to the seat in use.
  • What do I put at the bottom of the pits to start the digestive composting bio action?
    • Brian Says: You don't need to put anything in to get the composting action going. However you will want to put down pine needles, hay, oak leaves, yard waste or something as a base to improve airflow. I usually put about 6 inches of material. If you wanted to speed up or diversify the composting action, you could dump in some rotting fruit, native mushrooms, or other things which are composting. I also use composting worms and dung beetles which speeds the composting process.
  • What's the difference in cost and performance of a wooden, brick, mud, concrete build?
    • Brian Says: Costs will depend on what you have available and your location. Wood has the risk of rotting, though if you are combining it with pee gardens you will have less liquid. I use brick with a concrete base. I use wood in the seats. Concrete is widely available and works fine. Mud could be a problem for the base if there is risk of contaminating nearby water supply, and would have to be thick enough to handle the structure even though getting humid from urine. I might build a toilet with a cob chamber to test it, but generally I would stick with brick, rock, concrete for the chamber.
  • What is the ratio of poo pits and their sizes to numbers of users?
    • Brian Says: I am not totally sure. My toilets don't get steady use from a lot of people. The ideal would be to build the chambers pretty big, and be able to add more as needed. Experimentation is needed. It is better to have at least two toilets in shared environments so people don't have to wait for the toilet. The number of them to decrease wait time would use the same calculations as water based toilets. But two is way better than one. And of course pee gardens move a lot of users over to that system.
  • Which is best a sealed pits or locked pits?
    • Brian Says: The pits should be sealed against insects entering. I use ones which have imperfectly sealed chamber doors and seats and haven't had a problem. Vent tubes should have a screen. The doors should have a lock as sometimes curious people open them to take a look, then leave them open for dogs and wildlife to enter. Don't lose the key. I had thought about sealing the chamber doors with mud, but it is better to have ones which can be opened in case someone drops their phone or camera into the chamber. You could also have a pole with a light to grab dropped stuff. So far no one has dropped anything in my toilets. Some toilets in town had problems with people dropping garbage into them.


  • No need to divide toilets by gender. Divide by use. Stand up vs sit down. Divide out pee only vs both.

Urine diverting seats

Places which need them



Composting toilets
Composting toilets
Composting toilets
How I poop at the Bosque by Courtnee Fallon Rex

Drugs in composted soil

  • What are the problems with drugs in the humamuere and using them in gardens?
    • Seems like they would be the same as sewage.
  • Drugs in sewage
  • The composted humanure should make it easier to localize the drug waste because it isn't mixed into water.
  • If pee gardens have edible plants, to the drugs go up into the plants?


Eval these toilets