Composting Toilet
Nick and Sandy never really liked using a traditional outhouse or porta-potties for that matter; they are just nasty. For our off grid tiny house, we needed some off grid solution for dealing with human waste. Also, using several gallons of clean drinking water to flush a standard commode does not really make sense.
Side note: In Germany, many of the toilets don’t have water sitting in the bowl. They do flush with water, but you sometimes need to coax your solid waste with a brush to move things along.
In Korea, the trains have little porcelain holes in the floors of the restrooms. There’s nothing to sit on; if you must do a number two, it’s squatting time for you! You literally see the ground under the train. Not hygienic by any means and very off-putting while in motion.
So we discussed, debated, and researched. One toilet literally incinerates your waste, consuming a lot of electricity, but leaving you with dry ash.
After all that, we decided to go with a composting toilet, specifically a Nature’s Head brand (https://www.natureshead.net). The only maintenance the toilet requires, outside of periodic cleaning, is adding some peat moss or coconut coir in the poop collection bin to assist with the breakdown into black soil.
Reasons for Choosing of Nature's Head
- Lightweight
- Portable
- Odorless
- Compact but not tiny
- Self-contained
- No holding tank
- Made with stainless steel hardware
Pros and Cons
This solution comes with pros and cons. The Pros are it requires no black water tank, which helps with the stealth, mobility, portability, and ease of maintenance aspects. You’ll need a ventilation hose for fumes, and this should go to the top of the cabin or vehicle. Ours is the black plastic thing, image below, which is clever: even the slightest breeze creates a vacuum and therefor pulls air from the toilet, venting any bad odor. The toilet comes with two reversible vent hose nipples, one on either side. One gets a vent hose and the other gets a 12 volt DC computer fan. When necessary, turn on the fan and it will blow air across the inside of the toilet to the vent hose and out of the cabin or vehicle.
Nature’s Head toilet separates liquids and solids; but with this design, everyone must sit. The kit comes with a lid for the urine bottle, which seems important and easily lost. Nick made a holder for the cap and attached it to the toilet side; this way, we won’t lose the cap.
The Cons are everyone must sit. You have to empty the urine somehow, somewhere.
Daily Use
You must dump the collected urine, which is about once every other day for two people. You start with some sphagnum moss in solids tub and stir briefly after each use with the “spider” handle on the toilet’s side. The solids, including toilet paper, decompose naturally, and for two people, after about six months you dump out dirt. The solids tub really never fills up because the decomposing effect reduces the volume (but it will over time).
The vent hose has a 60mm computer fan to assist in venting when needed. We use a toilet vent that rotates freely and is cleverly shaped to create a vacuum whenever the slightest breeze is around, thus pulling (venting) the unpleasant odors from the composting unit. The vent below looks huge, but it is really only six inches or so tall. It rotates in the breeze like a wind vane.
Disaster Night
At some point during one night in the shipping container cabin, one of us tossed some tissue into the toilet, without the little flapper being open. The tissue plugged the urine holes. Urine filled the solids compartment, which began leaking. This was our fault, and created a nasty mess that was easily identifiable. In the morning, we detached the vent hose and power cable, carried the toilet out away from the cabin cleaned up the mess, refreshing the compost material. Back in business.
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