Our First Composting Toilet 11

You probably already know that I have had a roaring case of composting toilet envy. I read everything I can find about them. This week, with my bride in California visiting our children, I decided to take the plunge and build us one. Who knows, my friend, where this journey will end?

Our plan all along has been for a simple bucket toilet, a plywood enclosure around a 5-gallon plastic bucket with a lid that closes tightly. I have purchased four identical buckets from Home Depot (the “Homer” bucket – costs about $4.50 with lid) so we can put the lid on one and begin using another without running to the compost pile in between. Most of the heavy lifting compost-wise, the conversion from feces to humus, occurs not at the toilet – after all, it’s just a bucket – but in the compost pile itself.

I’ll probably have more to say about this in future posts, but the key to using humanure safely and effectively for agricultural purposes is to compost it at high temperatures, called thermophilic composting. The first step for us is to get started using the toilet. After we get the deer fence finished on Veg Hill and lay out rows and aisles, I hope to turn my attention to building the bins where the actual composting will occur.

The lumber was all scrap, and the screws I used to assemble it were left over from an earlier project. The hinges were $5.50 at Tallassee True Value, and the seat was about $6.00 at Home Depot. I started with four 2 x 2s cut to the same size and attached the front and back panel to them, made of 1/2 inch plywood. In perhaps an overabundance of caution, I provided diagonal front-to-back 1/2-inch plywood bracing inside the toilet, and then attached the side panels (also 1/2 inch plywood). The top is 3/4 inch plywood, just because that’s what I had lying around. 1/2 inch probably would have been fine. I threw out the little wood screws that came with the lap hinges and used small bolts, washers, and nuts instead. All joints are screwed; nothing is nailed or glued.

I made it up as I went along, with a couple of false starts along the way. Had I known about it earlier, I would have used the detailed plans and specs laid out beginning on p. 162 of the Humanure Handbook (free to download).

I’ve already figured out one mistake I made; I built the top of the toilet to be flush with the top of the toilet, and rested the toilet seat on the wooden top. That creates a tiny space between the bottom of the toilet seat and the wooden top, and it’s possible that something could splash into that tiny space and soil the wooden top. So I probably need to lower the toilet structure by about 1/2 inch so the top of the bucket will be more or less flush with the bottom of the toilet seat. The problem this will cause is that it will require that I reposition the little pedestals mounted on the bottom of the toilet seat so they fall outside the edge of the bucket. Right now I don’t know how to do that, because the little pedestals appear to be just glued on, not attached with screws.

The video shows us using wood ash as a cover material, again, because that’s what we have on hand. Wood ash makes an okay cover material, but there’s some concern that it might lift the pH of the compost and inhibit the composting process. In addition, we haven’t produced enough ashes to provide cover material through the long hot summer to come. Within the next few weeks, I need to come up with a local source of a better cover material like sawdust or leaf mold.

The video runs a little less than three minutes.

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11 thoughts on “Our First Composting Toilet

  • chuck

    Wondering how rigid are the sidewalls of the 5-gallon plastic bucket (and how firm are the connections from the bucket handles to the bucket body). A full bucket will be heavy.

  • Lee

    Good question. They seem pretty substantial. I know I can fill one of these up with water and carry it without a problem, and I would think water would be a good bit heavier than composting humanure, but I’ll let you know when we’ve filled up a bucket or two.

  • chuck

    A mix of wood ash with water would be another test; I don’t know what the density of the wood ash is. Maybe it’s similar to the density of water, maybe not. You certainly don’t want a bucket to fail!

  • Lee

    Whoa! Now there’s an arresting thought. Here’s my covenant: when a pooper bucket fails, there will be no video.

  • chuck

    Another thought.. could you offset the increase in pH from wood ash by adding oak leaf mulch? Up here, decomposed oak leaves are quite acidic.

  • Lee

    I don’t think there’s a need to do that. Our soil in central Alabama is naturally acidic, so raising the pH a tad wouldn’t necessarily be a bad thing as long as it doesn’t interfere with the composting process.

  • chuck

    I live in the self-proclaimed “City of Oaks” (yes, the official title) where it’s difficult for other flora to thrive. Not only do oaks suck up all the rain, they suppress competition by acidifying everything nearby. Every November there’s a frantic rush to rake oak leaves. Even so, we must frequently lime the soil before it will grow anything — except oak seedlings, of course.

  • Lee

    George, I think you’re asking whether we have a separate compost pile. Yes we do. The humanure compost requires special handling. We will deposit to the pile for a year and then let it cure for an additional year. Although I am comfortable that after that time the humanure compost would be safe to use on our food crops, we have decide out of respect for the squeamishness of our family and friends that we will use it only on the ornamentals.

    The other compost, on the other hand, is composed of everything else (shredded paper, food scraps, garden refuse, etc.). It’s safe to use as soon as it is no longer “hot,” sometimes in as little as a couple of months.

    So we have two separate piles.

  • Jonathon Meeks

    If you wanted to use an elongated seat you could use one of those plastic storage containers instead of a bucket.

    Also, I have to wonder why you didn’t install a composting toilette in the barn when you built it. There are models that flush, completely dry ones powered by electric vacuums, and some that use gravity alone. The main thing though, is that they come with all the convenience of being in the bathroom and not having all that hauling around to do. I think I might prefer an old fashioned two holer to hauling all that feces and wood ash back and forth. I think that you might be able to retrofit your barn with one, using the existing plumbing. If not, still something to keep in mind for future construction.

    Alternately, you could build a two holer on wheels on a platform above your compost pile and move it every year.

  • Lee

    I have done many things wrong here at Longleaf Breeze, but one of the things I KNOW I did right was the choice of a composting toilet. Simple, easy, odor free, and CHEAP. I’ll show it to you when you come. I may not convince you that I don’t need to spend good money on a “factory” composting toilet, but I bet you won’t convince me that I should either.