A “Flushing” Composting Toilet

I recently came across a youtube video by davidpaganbutler. It was showing off an old bucket compost toilet that had seen better days. What caught my attention was that it had a working 'flush' mechanism for dropping ash into the bucket. I could see this being used with pine duff, saw dust, lime, or other materials common to composting toilets.

One of the difficulties with non-flushing toilets is getting people to understand how to use them. I worked at a business for a couple of years where they had fancy compost toilets from a large company. Half of the people who came in either didn't bother reading the message of how to use them or didn't care. More than a few people seem caught up on the oddity of scooping something to toss in after their usage. I have no idea why that gives people trouble, but in my experience it does.

I wonder why there aren't more models like this in the modern age. It seems like having a clear 'flush' method would allow people to get accustomed to the idea much more rapidly and make an easy transition for people who are new to the concept. I wonder if anyone has seen a company making something like this or seen someone do a DIY project that recreates something similar? I sketched some ideas to myself and might one day try a project around it. If I do, seeing where others have succeeded or failed before me would be helpful.

The video is here:

I actually like the idea of a composting toilet that has a separator, like a trap door, that separates you and the bathroom from previous deposits. I would have a compound flush system, whereby the trap door, when returning to the up position after being flushed, has a layer of the dry flush material dropped onto it to accept the next deposit. The next flush would drop the deposit, atop the dry flush material that separates the poop from the toilet walls and trap door surface, down into the composter along with a secondary flush that tops it off and fills the trap door area again.

The dry flush material could be any dry granular material that will compost well, probably biomass from another process, like sawdust.

I think that I will have to investigate wet-flush composting toilets or invent one if they don't yet exist, although I think perhaps if I go that far, it will be a methane digester system. I think people have comfort issues where it comes to dealing with poop, and the more conventional an experience it is, the more comfortable and convenient it will be. Also, if it's just like the porcelain thrones they're all used to, there's nothing to screw up, so the system would work with fewer potential problems. Ideally, we'd be talking either about a biodigester that yields garden-ready liquid compost, or maybe a multi-stage process that separates water and solids and treats them separately, using things like reed bed swales (conventional swales, but intensively managed to maintain moisture, and probably with a series of internal baffles that make a seemingly straight swale zig zag internally, increasing surface area and length of time in contact with reeds and other filter plants and decreasing flow rate), into woodlots for water and Black Soldier Fly larvae for solids. In my climate, where the ground can freeze solid for months in a normal winter, I would need, perhaps, a low hoop-framed grow tunnel over the swale to keep it productive into the cold season and kickstart it in the spring, but these are details that change based on the specific situation.

-CK

Chris Kott wrote:I actually like the idea of a composting toilet that has a separator, like a trap door, that separates you and the bathroom from previous deposits. I would have a compound flush system, whereby the trap door, when returning to the up position after being flushed, has a layer of the dry flush material dropped onto it to accept the next deposit. The next flush would drop the deposit, atop the dry flush material that separates the poop from the toilet walls and trap door surface, down into the composter along with a secondary flush that tops it off and fills the trap door area again.

The dry flush material could be any dry granular material that will compost well, probably biomass from another process, like sawdust.

I think that I will have to investigate wet-flush composting toilets or invent one if they don't yet exist, although I think perhaps if I go that far, it will be a methane digester system. I think people have comfort issues where it comes to dealing with poop, and the more conventional an experience it is, the more comfortable and convenient it will be. Also, if it's just like the porcelain thrones they're all used to, there's nothing to screw up, so the system would work with fewer potential problems. Ideally, we'd be talking either about a biodigester that yields garden-ready liquid compost, or maybe a multi-stage process that separates water and solids and treats them separately, using things like reed bed swales (conventional swales, but intensively managed to maintain moisture, and probably with a series of internal baffles that make a seemingly straight swale zig zag internally, increasing surface area and length of time in contact with reeds and other filter plants and decreasing flow rate), into woodlots for water and Black Soldier Fly larvae for solids. In my climate, where the ground can freeze solid for months in a normal winter, I would need, perhaps, a low hoop-framed grow tunnel over the swale to keep it productive into the cold season and kickstart it in the spring, but these are details that change based on the specific situation.

-CK

That got me thinking some. Two days of sketching and I think I might have an idea of how to create a mechanism that works the drop gates as well as puts a set amount of biomass down, but won't put it there it until the drop gates close again. I'll have to transfer the images into the computer and post them here when time allows.

Did you ever get the drawings completed?