When using a vault toilet….

JaxDad wrote:
A friend of mine has a self-built Super C along the lines of what I’m currently building, it has a “vault toilet”, or as he calls it, “an indoor outhouse”.

It’s a cabinet of sorts with 2 large compartments, one is vented to the outside and with a sealed hinged lid over a hole and seat, the other a lift up lid. Under the seat is a stout (small) rubber garbage can. The second compartment is just the size to hold a bale / brick of sphagnum (pear) moss that you would normally use in the garden. To start there’s a thin layer of moss on the bottom of the receptacle then after each ‘addition’ another thin layer is sprinkled over top of it.

I’ve been in his unit after more than a week of him staying in it and tell you, there is zero odour.

The garbage can gets lined with a large sized biodegradable green bin liner inside a stout garbage bag. He has researched it all out, it’s completely legit to place it in the recycling stream, which he does.

I’m landing on doing the same thing in my unit.

Full disclosure, I grew up with outhouses at the farm, cottage, deer camp, etc, etc, so using one is pretty normal to me.

You are describing a "composting toilet".

I wouldn't recommend one for an RV (too easy to empty the holding tanks to be worth while for 99% of RVers) but we had one on our boat (much more of a hassle to empty the holding tank legally).

They work wildly different even though they may appear similar.
- A vault or outhouse, everything goes into the same place. This means the contents tend to be wet. Once the oxygen in the pile is used up, the pile goes anaerobic as the water surface creates a barrier limiting the ability for more oxygen to get into the pile. The byproduct of anaerobic decomposition includes nasty smells.
- With a composting toilet, the liquids and solids are separated. Ideally, the solids pile is moist but not wet (if it gets too dry, decomposition stops and you count on decomposition to reduce the volume). The peatmoss is used to generate air pockets and allow oxygen into the pile. By providing a steady supply of oxygen, the pile never goes anaerobic and smells are largely non-existent. When emptying, it smells and looks like potting soil.