We've gotten a landslide of emails (3) asking us for more details about a composting toilet in an RV.
You want details? You can't HANDLE the details!
[You totally can.]
WARNING: I am going to talk about human bodily functions and their results. I won't want to eat after I've finished this post, and that's my goal for you, too.
I've discussed this issue on public forums, and I've found that composting humanure in any way can
make people really
mad. I've warned you, now it's up to you to bring up toilets only very carefully as dinner party chatter.
Why compost?
An average RV toilet uses two quarts of water per flush, which is 4.2 pounds (plus the you-know-what you just did into that water).
- A couple might flush 10 times a day = 42 pounds/day (five gallons of previously-drinkable water)
- In one month, that couple has created 1300 pounds of waste that must be treated (including a rather conservative estimate of the weight of the urine and feces involved). This also represents 150 gallons of drinking water.
Many RVers divert their gray water for flushing, which is certainly an improvement. Still, the weight and volume of the waste remain the same.
Our composting toilet is pretty forgiving in the poo-storage department. A full vault is not a de-camping emergency. It will begin to ask politely to be emptied, and will not become belligerent for several days when it won't allow itself to be cranked.
However, timely urine removal is not optional. Please don't ask how we know this. However, delay is not a catastrophe like Isaac or Katrina. It will be contained, you just won't enjoy clean-up.
If you're talking about the same couple in a stationary home with a common low-flow toilet (1.6 gallons), the amount of treatable waste is more than two tons (4000 pounds) in a month. That's about 500 gallons of drinking water. If you're mad when you look at your water/sewer bill, imagine turning 4000 pounds of your own dookie back into drinking water and the bill will seem cheap.
The takeaway point is that our waste doesn't cease to exist after we flush. RVers know that when they drop the stinky slinky into that hole in the ground, but even then, it still lives.
Maybe you're an intermittent flusher; I'm cool with that. You can customize these numbers just knowing that a gallon of water weighs 8.35 pounds.
What's in it for me?
If you're a campground kind of RVer, maybe not much. I can't deny the bliss of never thinking about where poo goes after it leaves me. This is an excellent set-up for boondockers and homesteaders, and people who are seeking simplicity. You can't get much simpler than we are.
How to compost poop
I'll talk about the
Nature's Head composting toilet, just because that's what I know.
However, there are many approaches to RV waste management. Van dwellers tend to be very ingenious in this area (and in many others, too).
For two people, the Nature's Head poo-vault needs to be dumped about twice a month. The urine bucket in front (shown pristine white in the photo) must be dumped every two days, at least. Urine does not burn vegetation, and is safely dumped onto the ground. [Don't dump urine into a stream or other water body. Just because. A nice hole facilitates a contained dumping.]
If you feel you must occasionally flush something, take your urine bottle for a ride to a toilet and dump it there. This is just for you; your urine doesn't care either way.
We dump the poo into a garbage bag and throw it away. After two weeks in the vault, it weighs about 20 pounds. If we had our own stationary home, we would compost it for a long time and become our own solid waste management system.
A new friend works for a sewage treatment facility in Tucson. He tells me that medication being dumped into the sewer system is a problem requiring
a team of full-time lab workers. Untreated, the drugs are recycled into the aquifer and we get our diazepam for free. Nevermind the metabolites - he didn't even discuss that.
Drawbacks to composting poop
- You can no longer deny you poo
- After only two weeks, the contents of the vault will still smell a fair amount like poop
- Sometimes there are "glitches" in the system. The toilet may smell, or you won't get a full two weeks/ couple out of the vault. Humidity bogs down the system.
The ultimate solution to the main wrinkles is just dumping and starting again. That's as drastic as it gets.
While I am typing away on my sanitary keyboard, Annie is implementing a vault dump. She is smiling, but it's not a happy smile. This has been a glitchy two weeks. We can't compare this to going to a dump station, since we've only done that once, for graywater. Luckily for us, that one time involved other people's turds laying all around the overflowed tank.
You will have
gut reactions to what you have just read. Oh yeah, I said it. Hopefully I have addressed them, in snarky format,
in this discussion. We're glad to answer questions. If you feel argumentative after reading this post
and this thread, I'll respond depending on my mood at the moment.
As always, talking about a different way to do things is not meant to challenge traditionalists (much). Composting humanure has been a way to live the way we want to live, and it works. I'm not dissing conventional poo-management. Some of you may be looking for ways to get off-grid, and this is one of our Top Two modifications for off-grid living.
Free Humanure downloads.
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