my alternative technologies advisory commission wants to know

December 29, 2017 3:52 PM

I'm looking for "all known instances" of home-built 5-gallon bucket compost systems with separate composting chambers. Point me to links online, cite a book, tell me about yours, send me a memail. The more details the merrier. I will be sharing this information with my local government.

Please describe:
- your setup: urine diversion? leachate collection? open vs. closed pile? pile size? areation technique? carbon matter type? any other details?
- number of users
- maintenance schedule: How often do you empty the bucket? switch piles? turn the pile, if ever?
- lab test results (if any),
- how much it composted (if no test data)
- include the approximate date
- location
- building type


I will also be asking the permies.

(Previously: We have since learned that the international uniform plumbing code green supplement has code coming out that addresses 5-gallon homebuilt compost toilet systems). We should just have to do the paperwork to connect some dots locally.

posted by aniola to Technology (8 answers total)

To be clear: you want information about composting toilets, i.e. human waste, in 5 gal buckets? And you are not interested in composting non-human waste in buckets, or composting human excreta by other means?
posted by SaltySalticid at 6:13 PM on December 29, 2017

That's correct. Thanks for the clarification!
posted by aniola at 6:38 PM on December 29, 2017

I have DIY'd a version of the Roto Loo for a one-bedroom holiday cabin occupied for 60% of the year by two people. I used four 15gal buckets (60 litre rubbish bins) because four of them fitted in the two plastic stock troughs that I clam-shelled to create the composting chamber (which I then cut a small door in). The bins were on a rotating frame in the composting chamber. As one filled up, you turn the internal frame to position a clean bin under the toilet. That said, I think it took a month for one to fill (much of it wood shavings and paper). The filled bin has time to break down in the composting chamber before removing and lidding it for further composting before use/burial. The most important factor in the whole thing was the air circulation system.

For urine, I drilled drain holes in the bin and angled the tin on the floor of the composting chamber to drain into a a liquid collection pipe that I ran 50 foot out into the bush with holes drilled all around for the last 10 foot. An alternative to drain holes in the bin is a specially-built pedestal for a composting loo that has a urine separator built into the design.

I didn't get approval for this loo because it was on a huge rural property but if I was doing it more urban, I would buy one with all the specs pre-approved or get a sewerage engineer to approve my DIY plans.
posted by Thella at 9:01 PM on December 29, 2017

I have not had the need to do this, but I did, once, become aware of the term "humanure" which, combined with composting is likely to be a fruitful, if fragrant, search term. There seem to be multiple books on the topic that use that term.
posted by Sunburnt at 11:17 PM on December 29, 2017

I have a cabin in Washington state that is right on the river. Because it is so close to the river, we were told we would need a special septic that would cost 30000$. I don't know if that is true. The cabin came with an incinerator toilet which freaks my guests out and I think makes the neighborhood smell like burnt poo. So I put in a bucket compost toilet and ppl are ok with that. We let it fill up and then put a lid on it, let it sit a year and then put it in a compost pile which is not going to be used for food garden. Just flowers. Part of my plan is to have a grey water urinal. We have a greywater shower which is where ppl pee even tho they are not supposed to. So I tried to get a urinal put in but plumber said greywater urinals are illegal. Even tho you know everyone is peeing in the greywater shower. He also told me bucket compost toilets are illegal in Washington. I find that hard to believe, what about all the compost toilets in RVs? I think he just wants me to hire him to build a septic. So I plan to study greywater urinals to see if they are safe and then build my own. My biggest problem is the drainage freezing so I am planning to build a little greenhouse over the drainage.
posted by 17.5002 at 8:51 AM on December 30, 2017

Yeah. Part of the problem is that there are SO MANY examples of bucket toilet systems out there, and they (theoretically) want to know about all of them. So we had hoped to get first-hand responses to share.

I've also thrown together a survey for ease of checking off that you've answered all the questions, or for sharing with non-metafilter bucket toilet users.
posted by aniola at 2:16 PM on December 31, 2017

I unfortunately haven't had the pleasure of using a composting toilet system, so to those who are more in the know, I am probably stating the obvious- and kind of not answering the question as asked. I'll share it just in case it's helpful for making your case or for others who read this question, though. The number 1 thing that comes to mind for (public acceptance of composting) number 2 in a city setting is the Christchurch Earthquake. I found this writeup that gives a decent explanation of why composting toilets were a good solution in the aftermath- even after public sewer lines were repaired, the homeowners had the responsibility to figure out and pay for repairs of their connection to the main line. Any studies or documentation of the long term impact on the environment of people who used this system would be a great piece of evidence showing what a good system this can be even in the worst case scenario (quick startup, minimal training, using what's at hand)- although I suppose it's more useful for you to be able to show what normal operating procedures would look like.

Another idea- the city of Portland has put a lot of time and energy into supporting the NET program and disaster recovery community- so even though you're looking at a permanent installation, maybe you can tap into PBEM or the associated community. In my involvement with NET I have encountered more individuals that want to think and talk about composting toilets than I would have expected- perhaps there is a city employee or volunteer who has done some of this research already, but with disaster recovery in mind, rather than long term use.
posted by Secretariat at 2:59 PM on December 31, 2017

The house is approved. We can legit shit in a bucket.
posted by aniola at 2:07 PM on December 19, 2018