Jack Banks

Rebecca Norman wrote:I don't understand two things in this diagram.

1) What's the diameter of the pipe?

2) What's the rest of the structure? Are you imagining poop going straight into the auger, or the auger lying horizontal at the bottom of a pile?

Our composting toilets here are big manure chambers at ground level, with the user's toilet room upstairs. Two manure chambers (3 x 8 x 8 feet) under each user's room, so that we can leave the manure to compost for a year before removing it. When I lived at a school with dozens of people using a few of these, and using soil as most of the cover material, I sometimes thought an auger lying horizontal in the bottom would be good. You could leave the chamber always about 3 to 5 feet deep, and slowly be removing the bottom of the heap with auger, so that it would re-aerate and do more decomposition in an external pit before being removed by us humans.

Now at my own private house, I again have two manure chambers (3 x 8 x 8 feet) downstairs, and the toilet room upstairs is attached to the upstairs back corridor so you can stagger out of bed in the middle of the night and not go outdoors. I'm using sawdust as cover material, often mixed with crumbled leaves or coffee grounds, and dampened for a few months before use. There are only 2 to 3 people using it. When I emptied one of the primary chambers last November into the outside (secondary) compost bin, it really wasn't a big job. A friend helped and we finished in 3 or 4 hours. It didn't quite fill a 3.5 x 3.5 x 4 foot bin, and was very lightweight. What made removal slow was the chamber being narrow so it's hard to use the shovel, and having to pause to remove plastic, bones, wood and stuff. Nothing looked or smelled poopy, and I'd closed off the chamber the year before by topping it with a few big sacks of leaves and then occasionally watered it from above, so there wasn't too much recognizable toilet paper on the top. When removing it from the primary chamber, we just put the paper and dry leaves in the bottom of the secondary bin just outside so they'll be composted by the time I dig all the compost out. Removal is not a big enough annual task to justify mechanizing it with an auger.

By the way, for smell-free decomposition to happen, it needs to be aerobic, and it doesn't look like it'll be aerobic inside that pipe. Anaerobic decomposition is slower and much MUCH smellier. Also, external heat is not generally needed for decomposition, and wildly fluctuating temperatures (like if it gets heated by the sun and then freezes overnight) are likely to hinder decomposition by killing off different species. Good composting happens when there's a big volume of material all together, keeping itself damp, warm and at a fairly stable temperature, and well supplied with a thriving and robust ecosystem of hundreds or thousands of different species of decomposers.

Yea that's kind of the idea is that the material would build up on top of the auger before being augered out. Like basically a normal composting toilet on top, but instead of having to empty the bin all the time you would just give the auger a turn or two as needed.

I got the idea for leaving it in the sun from the composting bins we have around here. They're black and the heat from the sun supposedly helps kitchen waste decompose faster. I figured the same principle would work here.

If not, though, the pipe could run underground. That would keep it at a constant 55 degrees year round.

Mike Haasl wrote:Farmers have some pretty long augers (20+ feet) for pushing grain up into silos.  

That could definitely be an option. Might be an advantage since it might continuously mix the material.

Mike Haasl wrote:Maybe, it has promise.  Would the auger go all the way down the pipe or just past the poo hole as drawn?

I think a couple challenges might be:
1. Poop not getting pushed by the auger and just getting smeared around on the auger
2. Auger probably doesn't have to be that large a diameter but the holding capacity of the tube has to be a certain size to give the dwell time needed to compost.  Not sure if there is a pipe diameter that would meet both criteria
3. Does air need to get into the pipe to help with composting?  If so, how's it get in and out?

I doubt there's any auger available that's that long. Shouldn't be a problem though. Assuming the auger is braced against something solid, it should be able to push the material through the pipe. The pipe would be braced against something outside on the exit end. The only real force the pipe would be subjected to is the friction of the compressed material on the sides. The compression of the material may even help. Should generate more heat that way and thus accelerate decomposition.

The idea is to keep the auger covered at all times. The riser pipe would be kept at a certain level, and fresh leavings would be covered up with sawdust or something, just like in a normal composting toilet. Then the riser pipe would have an exhaust to draw smells out the roof.

You can probably tell where I'm going with this. It would work exactly like a composing toilet, except instead of having to empty a container, the auger would push the material through the pipe (after mixing it), and by the time it arrives at the exit it's mostly decomposed and hopefully odor free.

The pipe would be about 15' long and mostly exposed. The exterior would be painted black to absorb sunlight and heat the tube and accelerate the process.

I've seen people do this with a gravity feed system, but then your outhouse has to be 10 feet in the air, which is less than ideal from several perspectives.

I have 20 acres near OKC, and I'm wanting to start a small tiny house community of homesteaders. There are enough utilities for 3-4 tiny houses, and plenty of land for everyone to have a garden, chicken tractor, and some grazing animals.

I just don't know where to start, so I'm looking for that first person to be my guinea pig.

denise ra wrote:Are you insulating the container on the outside or the inside?
Do you have a well for water? There is a thread, which I'm sorry I can't find at the moment, about cooling with well water.

That's definitely interesting. There are two challenges with water. We don't plan on doing a well because the ground water is heavily contaminated with farm runoff, so we'll opt for a catchment system. Which actually goes hand in hand with the earth tubes since we can dig for the tubes at the same time and save some excavation costs.

The other issue with water is that it wouldn't provide any opportunity to remove humidity from the air. That's probably the main reason we really like the earth tube idea is because we can continuously recirculate the air in the house through the tubes and pull that moisture out.

Aaron Yarbrough wrote:I've been thinking a lot about earthtubes lately. I'm planning to rent a mini-excavator in May to install a septic system and installing earthtubes is a side project I've been considering while I have the equipment on site. Currently, I'm considering two 60 foot runs of 4" pipe buried ~6' deep. The runs meet at the end at a vertical well where they could either be connected to create a closed loop or optionally left open and air could be pulled from both. I'll make a sketch and post it here in the next week to give you a better idea of my plan.  

I've heard that 12 feet plus is required, but maybe it's different in your area.

So I'm trying to figure out some solution for off grid air conditioning in central Oklahoma, and earth tubes are the only option I've not yet exhausted. This would be 100% geared towards cooling the air in the Summer, as heating here isn't a problem (a small wood stove like a Dickinson is more than sufficient).

Basically what I need to know is if a closed loop earth tube is capable of providing any appreciable cooling on its own. What I like about the closed loop design is that it's going to continually remove humidity from the air like a traditional AC unit would do. I know it's going to require a fan, but we could easily spring for enough solar panels to do a DC fan to keep the air circulating.

I had also thought about doing a kind of hybrid system where you would have an intake in the tube, along with a solar chimney in the roof. That would give us the option of switching between open and closed loop just by opening and closing vents. Generally speaking, I like the idea of having continuous fresh air, but would want the option of closing the loop to maximize efficiency for when it gets really hot out.

The type of building I want to go with is a 20 foot shipping container with insofast insulation, which basically turns it into a giant thermally broken cooler. What really attracts me to the shipping container is that it can easily be lifted off the ground on piers, and the ideal build site on the property is in a flood zone A due to the creek. I know the earth bermed stuff seems to be preferred here, but there are two big issues with that in this area. First of all the cave effect because of our high humidity, and then the flooding issues.

Another challenge is that we don't have the time or energy right now to build something so labor intensive. We've looked into earthships and earthbags and cob and all that, and the reality is that it would probably take us years to finish something like that. So the shipping container option is more realistic since it's turnkey.

It seems like the earth tubes would be better for us anyways, because they use the same thermal mass principals as a bermed house, but remove the humidity rather than bring it into the home. I've been in basements in this area and while they're cool in the Summer they are always extremely humid. In order to control moisture in basements here, you have to insulate the outside walls, which of course cuts off the thermal mass.

Leigh Tate wrote:Jack, welcome to Permies! My husband and I gave up air conditioning about 6 years ago and we live in South Carolina. Granted, we don't get quite as hot as you do; typical summer highs here are upper 90s with only occasionally topping out over 100F. And we usually drop into the 70s at night. I don't know if you have a lot of humidity, but that's a real problem here when the weather is coming up off the Gulf.

I think your idea of a straw bale house is worth looking into. We bought a nearly 100-year-old house which we have gradually upgraded for better energy efficiency. We've done the things suggested here, along with the common sense methods of shade trees, pulling in cool air at night and then closing the house up during the day, keeping windows on the sunny side of the house covered, use a summer kitchen for summer cooking and canning, and installing a solar attic fan (that helped a lot). In the heat of summer, our indoor temperature tops out in the mid-80sF. Warmer than what most people are used to, but tolerable with ceiling fans. The benefit of not using air conditioning is that it isn't such a shock to one's body when going outdoors. We're not going from 70* to 95*, we're only going from 85* to 95*. We avoid the draining sensation of physical, mental, and emotional wilt every time we go outdoors (and because of our lifestyle, we're outdoors a lot! As an aside, I hate errand days, when I have to go in and out of multiple air conditioned stores. The temp differences are a shock to my system.)

My two biggest challenges are:
1. the humidity
2. food storage

We tend to have bad humidity anyway, but in the house--even though I don't cook or can inside--we still use the sinks and showers. I have to be constantly vigilant against mildew. Good air circulation helps, so we have fans running almost all of the time.

Food storage is more challenging because, of course, warmer temps decrease shelf life. We don't have a root cellar because our ground temperature doesn't stay cool enough in summer to probably make the effort and expense of building one worth it. My pantry is the best insulated room in the house, but only stays several degrees cooler than the kitchen. I have seriously considered what John said about a small air conditioner for the pantry only. I've crunched the numbers, and he's right, it's feasible to run a very small window unit from solar.  

Going AC-less wasn't an easy decision to make. Even now, I have to constantly remind myself is that summer is hot and winter is cold, and that's just the way things are. As others have said, humankind has lived most of its existence without indoor climate control. So personally, it's a decision I'm glad we made. In a way, there's a sense of freedom in it, both physically and financially, although I realize such a decision isn't for everyone.

Yea if our nights dropped down into the 70s I could handle it. Unfortunately in high Summer the nights don't cool off very much, if at all. Maybe five degrees is pretty typical, and I remember times when it would actually get hotter at night.

John F Dean wrote:You never say if you will be on grid or off. The size of home comes into question as well.  So do things like your age and if you will have others with you. So, I will shot gun my answer.  I doubt if everything here will apply to you.

1.  Have a metal roof to reflect the sun .   Make sure what is under the roof is ventilated.  
2.  Design for an attic fan, even if you are off grid. Things change.
3.  Have a screened sleeping porch.
4.  Plan windows with prevailing winds in mind.
5.  Design one room to take a small air conditioner.  I realize that people lived for thousands of years without AC.   But a $100 AC and a small generator could save your life. You don’t have to run it all the time. Besides, a small AC can run on solar.
6.  No matter what kind of house you decide on, keep in  mind you may want to sell it some day.

We would like to go off grid, because there aren't utilities on the property. Bringing them in would cost a small fortune. Unfortunately so would running AC off solar.

Living without AC here isn't an option. Even when I was younger, camping in the Summer was unbearable.

The only way we could go off grid is if we could find a viable building style that would stay cool even in the brutally hot and sometimes humid Summer months.