Better composting toilet?

We're looking at composting toilet designs for the campsite. First choice is the Farallones design, same design used at Zaytuna Farm, with concrete composting bunkers. Our concerns about this one is the difficulty of building that much masonry without running water. Second choice is a plastic bin system which would have the addition of worms to help compost once the bin is filled. Bins will be swapped out when filled, and set aside to compost. This requires the moving of the bins. There's also concern a bin system will smell more because the bin won't be surrounded by a concrete bunker. But construction will be much easier because of no masonry.

Which do you think is better? Or is there another design preferable to either of these?

http://permaculture.org.au/2010/03/04/life-at-zaytuna-closing-the-loop/

Rammed earth or adobe with a waterproof plaster? Dry stacked concrete?

It doesn't take much water, and it is all at the same time, to put surface bonding concrete on top of the block stack. Easy to truck in using a couple barrels or IBC.

There design seems to be pretty good for a dry climate. If you were in a wet climate, I would separate #1 and #2 as much as possible to reduce odor issues...

I think it's going to be mortared concrete block.

No-go on the plain old humanure set-up?? Just need to find some kind of sawdust source, a year's supply isn't that much. I don't find there are any odour issues. Chores aren't a big deal. The book is cheap and the infrastructure is quick and easy to throw together if you want to try it for a few months.

I just mention it because it seems like it would be a lot less work and less resources...i wonder if you would have to add some water to it down there in texas?

cheers..

If you have access to wood chips or other high carbon organic material why not just go with humanure.
kent

add some privy flies. even in a system not designed with them in mind, they'll churn things up, keep it aerobic, reduce volume, and keep pests away.

Thank you for the suggestions. I've asked about this a couple places and it looks like the traditional humanure bucket system is the most recommended.

I prefer replacing the buckets with 50-gallon plastic drums with toilet seats on top. no emptying shit buckets needed, but otherwise very similar to Jenkins' humanure approach. adding Eisenia foetida and Hermetia illucens speeds decomposition and circumvents the need to aerate.

depending on use, put two right next to each other. after one is filled, use the other while the first composts. when the second is full, empty the first and fill it again while the second composts.

That's sort of what we're looking at, tel, except we're looking at 30 gallon drums because they're lower and less heavy. Plus the worms. Trying to avoid the emptying shit buckets part.

Tyler Ludens wrote:That's sort of what we're looking at, tel, except we're looking at 30 gallon drums because they're lower and less heavy. Plus the worms. Trying to avoid the emptying shit buckets part.

it's worked well for me. I buried the drums about half their height so they're at a comfortable level. moderates the temperature, too, so the critters keep working in the heat and cold.

two of us using it full time need three drums, though if we get the privy fly population up, I'm sure two would be plenty. worms are great, but larvae are a lot faster. we also put a fair amount of kitchen scraps in there, which added to the volume significantly.

Did you have any odor problems?

Tyler Ludens wrote:Did you have any odor problems?

nope. we just make sure to completely cover each new mess with sawdust. I worried that dumping a big pile of stinky and slimy kitchen compost in there would throw things off, but even that was fine once it had a sawdust cap. when it comes time to empty a barrel, it's all pretty pleasant. keeping rain out is important, though. the one that got rained in was pretty nasty and anaerobic at the bottom. we also used shredded paper instead of sawdust for that one, which could also have contributed to the problem.

I forgot to mention that we prime each barrel with finished worm compost, a couple of scoops of sandy dirt, and some rotting leaf litter. I don't know how much of a difference all that makes, but the dirt at least is necessary to provide grit for worm digestion.

Thank you, that is all extremely helpful!

My favorite outdoor composter is for establishing orchards..
Put 4 straw bales in a ring on the ground (no digging, maybe loosen the earth underneath with a fork) and place a deck on top with loose planks. One (or sometimes two) of the planks has a handle on it. You lift the plank with the handle and squat over the slot. Cover yer business well with wood mulch (or what have you) and replace the plank. When the space is full, move the planks with the handle over one space and repeat. The pile works as you go (and shrinks), so when you get to the end you should be able to start at the beginning, at least a second go. When the thing is totally full, you cover with mulch and let compost for a bit, when it's done cookin' you plant a tree in it.
This is a GREAT way to establish an orchard.. You just set up the toilet where you want a tree, when it's full set up at the next tree to go in and repeat.

'Course, when the orchards in, you'll need a different system...

I like the straw bail thing but Im sure animals would get in it here and we dont have any straw. Animals make a mess if I try to copost manure in the regular heap. Who uses this campsite and how much? Douse it need a structure? If its very remote I would just burry the poo. If its not remote I would build a nice low maintanance system - a big two chamber system. If it ever rains, you have water. Hange a tarp over the building site so that all the water runs to one point. Dig a hole and line it with plastic under that point. Wait for rain. A time to sew, a time to make cement. Mulch works better then sawdust but can be buggy. Worm managemant can happenin iether system. The compost is valuable to me, I feel I am making a positve contrabution, and I'm so stingy I avoid pooping other places. ps wheres the spell check?

Thank you for these ideas! I think we've come up with a design which will work for the situation. I'll be sure to post a picture of the plans when we have them drawn up.

Tel, do you mean to say that in your winter climate, the privy flies (bsf, I'm) survive and continue to process manure? Does the temperature 1.5 ft below ground, plus the heat they generate themselves, keep them optimally active? How fast are the 'deposits' converted? Where do the larvae go to pupate in a straight sided barrel? Can you describe the end result.. larvae convert poop to fly 'manure' and worms finish it into castings? And no drainable holes are needed... just an organic base? Details, please, on the cool weather temps and operation :) And, can you confirm the odorlessness, again?

And, Tel, do you separate urine?

Here's Milkwood's (Aussie climate) bin system - http://milkwood.net/2011/04/18/compost-toilet-specifics-the-bins/

nancy sutton wrote:And, Tel, do you separate urine?

we don't separate urine. we don't use the composting toilets if it's just a liquid deposit, though. if there's a bit more urine involved than usual, I add more sawdust to soak it up.

regarding the privy flies: they do survive just fine. they don't remain active in these toilets over the winter, but they survive as pupae and hatch as adults when the weather warms up. you've got the basic idea, though: larvae churn up the top layer, and the worms work at lower levels. soldier flies don't really like added carbon, and I'm told the pH doesn't end up being great for the worms due to the larvae. so it's not ideal for either species, but they seem to get the job done working together.

and yes: no odor. remember that everything gets covered in sawdust, then left for at least a year after the barrel is full. our success with such a simple design is likely due largely to the small population of regular users. it's just two of us with occasional visitors. and the visitors tend to be around when the helpful critters are most active. when the soldier flies are really active, their distinctive odor is certainly present, but that isn't objectionable to most folks.

a bit more thoughtful design could pretty easily accommodate more folks, though, without being too much more complicated. an escape ramp for the soldier flies and a simple spot for them to lay eggs would help increase their population pretty quickly. diverting urine could reduce the amount of sawdust required, possibly to zero. adding an open bottom to drain to a reed bed with an impermeable bottom would be another way to reduce sawdust, though reeds aren't actively growing around here for several of the colder months.

we're right now in the process of moving away from the spot with these toilets. I'll probably be emptying the two remaining full barrels sometime in the next couple of months. I'm planning toilets for a couple of other sites, too. one in a fairly conventional house inside city limits, and another in a four-season greenhouse. I'm certainly no professional, so we'll have to wait and see how both of those work...