compost toilet heap designs

We have two buckets for our toilet and we ask the users to only poo in one and mainly pee in the other. Both have fine timber shavings for the cover material which we get delivered free from a local carpentry shop. All house hold compost goes in with the pee and put in dalek style compost bins in the veg garden. I wish to compost the poo (and some pee) bucket separately. Since July I have been filling two plastic drums, holes in the bottom, lids on top. But they are not really decomposing/reducing as much as I expected, but I guess it is winter but not particularly cold. I don't make enough compost to run a meter plus cube heap that the bucket gets emptied into the middle of as in Joseph Jenkins idea. Please can you suggest any other compost heap/bin ideas? I would like to try a few different designs, eg making two concentric wire mesh cylinders and filling the outside with straw and emptying the toilet in the middle? When folks fill wheelie bins do they just let it sit for a couple of years? Mix in any other material? All the toilets with urine diverters - what do you do with the solid? Just poo and shavings sitting in a plastic bin (with holes in the bottom) just doesn't feel right but it seems to be a method?

thanks for your help

I would just add red wriggler composting worms to your existing barrels and let them sit for a full year from the last deposit.Last thing you want to do is mess with moving it from the barrel before it is done composting.
In the future, your straw cage idea sounds good, but building one from bales would be easier. A black tarp could help maintain moisture and tempature.
Another way to improve how quickly it breaks down to agitate it. There are augers specifically made for stirring the uh, shit, or you might be able to find a ice fishing auger cheap, depending on where you live.

Are you in a hurry for it to compost for some reason? If you have a smaller pile and don't think it's getting hot enough, the easiest thing to do would be to just let it sit an extra year. You said you want to compost kitchen waste and urine separately, but if you put it all together you'd probably get a bigger, hotter pile.

I tried composting my dogs' crap in a garbage can kinda deal one time and it sat for two years and didn't really break down at all. Too sterile when not exposed to the elements, too dry? I dunno. But I like everything in a heap on the ground now.

Haha - I guess sterile isn't the word to use when describing shit... but you know what I mean.

I'm in no hurry at all it's just exactly that - a plastic bin with just poo and sawdust felt too sterile for a compost bin!

I remember one summer about 40 years ago my dad had me dig a big hole in the side yard where we let the dogs out. He took a full-size plastic garbage can and drilled a bunch of holes in it. Then we set the can in the ground so that the top of it was a couple of inches above the ground - just enough to get the lid on it securely. Then when I would clean the dog poo I'd just drop it in the can.

Well, the can filled up a bit quicker than we'd planned, having two big labs. And it was too much work for our urban sensibilities (at the time) so we didn't dig another. We forgot about it for about a year. Then I took the lid off and what I found was a whole can full of the best black soil.

I tried replicating this a bit over a year and a half ago, and it didn't turn out as well. I think we just don't have enough worms in the ground here. So your biological conditions can be an important factor. Adding worms should help, though.

that worm composting thing should make a difference in how fast it breaks up.

i think, it might get too cold for compost worms in winter in an exposed bin. but they would do a much better job than garden worms alone. they reproduce much faster and work faster. i think, they like fresh poop, which i think garden worms would not touch until it s partly decomposed...
with pee and greens (nitrogen) the bin might get hot enough for compost worms. but it should not get too hot for them. so it s about finding the right balance.

it would help to bury the bin at least partially (with holes into it), so garden worms can come in easily. maybe you could pile earth or straw around the barrel to provide insulation. garden worms are a bit tougher than compost worms and would just move deeper when it s too cold and return when it s warm enough.

i am thinking a how to process small amounts of poop (a few doses per week maybe) in an allotment-garden (completly off-grid). i think, i ll bury a pipe with holes and put the stuff down there. i ll add some garden worms and kitchenscraps. and a cover to protect from flies and rain.

Cesca, here's how we've been doing it for years:

Make a straw bale container, two bales on each side, 8 bales total. The reason we use straw bales is that the bales themselves add a little heat. Ours last about one year before they are too broken down to be walls anymore.

I put a layer of small branches in the bottom 6 inches. Into this bale cube goes all waste. I mean everything that isn't plastic or otherwise oil-based. We run 5 buckets of combined waste with a specially made "toilet shavings" mix, it's fine wood shavings, peat moss, and a little char. This gets tossed into the toilet whenever someone uses it. Once 4 buckets are full, they get dumped into the cube. This is the only part that generates odors. These 4 buckets are enough to make a layer about 2 inches thick in the cube. The next layer is roughly 4 inches of loose straw, which keeps the odor from escaping. Dog poop gets the same treatment. This goes on until the cube is almost full. It will have started heating by the time it's a foot deep, though. Each layer you make will heat, then cool.

When the cube is almost full, I guess how much carbon to nitrogen I have. Yeah, not real scientific, but it works so far. If I think it needs more N, I add chicken litter. If for some reason it's got a lot of N already, I'll add wood chips. This gets mixed and re-piled, and then it gets HOT. I've seen piles stay hot for 6 weeks. While this pile is doing it's thing, I start another.

We usually turn/mix the piles a few times a year, and use the compost after about one year. You can plant heavy feeding plants straight into it, but usually we spread it. For most potted plants I mix it with bark fines, about 50-50 is more than enough.

It doesn't matter how long you take to build the pile, so long as you are not volatizing N, so keeping your urine separate is actually a great idea. Mix it in once you've got a yard or so. Urine can be stored in closed drums or buckets, they've done some interesting studies on that in Africa. I've noticed that when you store urine, the pH goes up, and crystals form, probably struvite. This is easily avoided by adding a small amount of sulfuric acid to the bucket. I buy battery acid (35% H2SO4) and dilute down to 8.75% (4:1) then add 100 ml of this to a bucket BEFORE I start peeing in it. If you add H2SO4 to an old bucket of stale pee, you will get a NASTY reaction, don't ask me how I know...

Hope this is helpful! By the way, our red worms won't touch the stuff in our compost piles till it's been turned several times, I don't think they like stuff "raw".

I have easily the best soil out of anyone I know, and some of these people have been gardening way longer than me. I attribute this to humanure and horse poop, two things most people will say to never use in your garden. Oh, and tons of red worms!

hey jim...

nice post, thank you.

did you try if the worms would touch the stuff in a non-hot environment? maybe you could experiment?
i mean, your pile will heat up alot and quickly. that will be too hot for the worms. and in the straw there s nothing for them.
i read stuff where one had a bin just with worms and dog-poop and it worked.

Hi,
Joe Jenkins, the author of the Humanure Handbook and greatest proponent of the bucket system you are trying, says emphatically in that book, that you should NOT separate poo and pee, because poo with sawdust is too dry and perhaps low in nitrogen for all that sawdust, and won't decompose.

I think if you feel you don't have enough humanure or enough space to make a big compost heap like Jenkins recommends, the suggestion above about putting a barrel with holes in the bottom, partially buried into the garden soil, and using that as a mini-compost bin, sounds like a great idea.

I've had particularly bad luck with trying to keep urine and wood shavings or leaves in a closed-bottom plastic container. It goes anaerobic and produces methane, stinks, and does not compost very well AT ALL. I've stubbornly done it three winters in a row and it's just as bad every time, even though I think I've solved the issue each time. The idea above, of a barrel with holes in the bottom set into garden soil sounds like it would solve a lot of issues, and I'm going to try it.

I don't think you'll get very good decomposition if you keep your manure in the original airtight buckets for a year, and your back garden will fill up with mysterious buckets that your casual visitors might ask about.

I remember many years ago seeing something called a "doggy dooley" where you buried a plastic bin with holes in it, where dog poo was supposed to disappear, sounds very similar to what you are talking about.

One bucket fills up in 4 days at our place, then gets dumped within two weeks, so I don't know what would happen to a sealed bucket over time. Probably off-gas quite a bit, blow the lid off? I don't know. I don't seal our buckets, I put wood shavings on top, no odor.

I store urine in a bucket with no shavings. It is 5 gallons, has a spigot at the bottom, and a sealed lid with a pour spout. In the pour spout is a funnel, and in the funnel sits a light bulb that gets removed when I, er, make a deposit in the N bank. As I said before, there's a bit of sulfuric in there to begin with, to control pH drift and precipitation, and it doesn't smell good, but you can't smell it with the light bulb on top.

Here's where I got this idea-

https://www.mtu.edu/peacecorps/programs/civil/pdfs/ryan-shaw-thesis-final.pdf

Scroll down to pg 17 to see a system very similar to ours. I do not use this exclusively, I use it mostly when I'm working in the yard, and don't want to walk back to the house to go.

BTW, if you put urine into something with holes in the bottom (like the doggy dooley) you're going to lose almost all your nutrients, and get a serious hot spot at the bottom of the container.

Tobias, I've just started two new worm bins (after roasting the last one with too much greens). After a bit I'll try your suggestion, if I can make it not stink. I'm under strict orders not to create any more smells than I am already, I left a bucket of willow twigs to root and forgot to change the water. Roots? Yes. Stench? YES!!

fantastic thanks. I'll bury the bottoms of the bins a bit to make it easier for whoever wants to get in! I moved one of the bins yesterday and there were compost worms underneath. I add pee to try to adjust the moisture content only, its not 'wet' as such and they are lidded, and they are by a mulberry tree so any leachate will not go to waste.
the straw bales seem a good idea if they last about a year volumetrically and structurally it can then be covered over for its resting time. neat. only draw back is paying money for good straw!
On the pH topic; I have measured that stale pee is about pH10 , which is why you are adding battery acid Jim. Is there any reason why battery acid? why not vinegar?

i would not add too much pee when doing worm composting. it might get too hot for them. i d add some other organic material and maybe some water (only when needed). worms prefer it moist but not too wet.

I use H2SO4 instead of vinegar because vinegar (5% acetic acid) is far too weak, and H2SO4 is much cheaper. My soil is also poor in sulfur, so the acid is perfect for this use. Note that the pH of stale urine goes up over time, it does not start out that high. If you prevent the pH rise, you also prevent struvite precipitation, which keeps all your minerals in solution. If you don't control pH rise, you'll end up with "sand" in the bottom of the bucket, which is the Mg & P, combined with some ammonia. This means the urine will be less suitable as a liquid fertilizer, and you'll need to add the struvite to your compost. Not the end of the world, but it's easier to simply keep it in solution.

No, worms do not like pee, it generates ammonia in the soil. Even too many greens in the bin will create ammonia, which will drive out the worms. If you are keeping urine separate, dilute it 1:1 with water and water your fastest growing plants, the mulberry will love it.

Yes, buying straw sucks, but after you've used them for the bin, you can mix them into the compost as cover, or plant straight into them. It's not a waste of money, IMO.