Burton Sparks

M Ljin, thanks for sharing your experience!  Major factors affecting drainage include:

1) Media:  Must be fast draining.  Mixing sizes of media, or mixing media that breaks down at different rates (resulting in different size media over time) can run the risk of packing and preventing flow.  vermifilter.com recommends media that breaks down more slowly, like pine bark.  The Institute for Transformative Technologies is leaning toward non-organic media that won't break down.  The same principle applies with the gravel layer.

2) Surface Area: The surface area needed for a primary digester depends on the number of people, whether or not toilet paper is used, and if you're adding greywater (higher hydraulic loading rate).  If you're flushing toilet paper, vermicompostingtoilets.net recommends a maximum of 4 people per IBC tote.

3) Worm Population: Without enough worms to keep the media porous, it can clog.  Worms in general work faster at higher temperatures, but they can die if it is too hot.

4) Outlet Drainage: I believe some systems have failed because they require pumps at the output to lift the effluent.  If the pump fails or outlet backs up, the system can back up.

In the images you show, I wonder if the vertical perforated pipe (drainage assembly) is more likely to clog given how close it is to the inlet where fresh deposits are made.  Is there a way to move it in the corner, or perhaps all 4 corners?  I plan to use the "drainage assembly" design at vermifilter.com, where all 4 walls can drain, reducing the chance of killing the worms should something clog.  You could line the walls of the IBC tote with drainage cells to achieve a similar level of drainage assurance.

Emilia, my understanding is that soil clumps are created at the micro level from bacterial glues, and at the macro level from fungi and worms. Worms help neutralize pH, but it is fairly easy to obtain a soil pH test if you want to see where it ended up after composting.
If compost gets too dry bacteria will try to protect themselves by creating a hydrophobic bubble to retain the interior water around them, but that makes compost repel water on the outside as well, making it very difficult to rehydrate compost. Do you use mulch to keep the applied outdoor compost moist?
Are plants not germinating while the compost is still moist? Germinating seeds in straight compost can be difficult, as compost can introduce pathogens and fungi that may harm seedlings, especially if the compost is not fully mature or sterilized.
Anaerobic digestion is inherently slow compared to moist aerobic composting.

Vera Carrera wrote:Can you estimate at what distance from the ambient environment there is still a temp of 60°C? for instance, if the ambience has 20°C .

Yes, it is possible to predict temperature fairly accurately if you have a consistent recipe and can manage the environment and how the pile is constructed.  This is described in Chapter 4 of The Mushroom Cultivator: A Practical Guide to Growing Mushrooms at Home, by Paul Stamets and J.S. Chilton.  The temperature a compost pile reaches, including the shape of the heat profile map and how close to the edge reaches pasteurization temperature (inches vs feet), depends on several factors, but you can learn to control them.

I've measured temperature in dozens of piles over years, tried pasteurizing in a bucket (albeit not mesh) within a pile, and dabbled with ways of adding air.  I primarily do a passive center-feed hot composting method advocated by Joe Jenkins (see pg227 here), year-round from -27F to 100F in an arid and somewhat windy area, and I can control and adjust the temperature in those piles to within about 10F.  I would recommend using a compost thermometer to help you get familiar with your recipe, the impact of how you construct the pile, and to provide you with the final confidence you may be looking for.  In my experience, protection from wind and a foot of straw insulation on all sides, bottom, and top can help ensure predictable temperatures for a consistent recipe.  Also protect from excess rain if applicable.

Aerated Static Piles, such as O2 Compost, use forced air to give you some degree of after-build temperature control as an additional option.

Devin Baty wrote:I guess what I'm curious about is if there's a quick indicator that low oxygen content isn't a problem? I had hoped to avoid having to do too much turning, so if I could feel confident that the presence of bugs or worms signaled that turning wasn't necessary to introduce oxygen, I'd be content (I understand that there are other benefits of turning, and also that oxygen introduced by turning often is quickly exhausted - oxygen levels return to normal very quickly).

Devin,  A simple check of oxygen levels in a hot compost is to see whether or not you find that white powdery stuff (actinobacteria) that thrive in the transition zone between aerobic and anaerobic.  On a related note, if the pile is not hot, you could check for excess moisture that could cause an anaerobic condition by squeezing a handful of compost in your hand and seeing how much water comes out.  A few drops is just right for hot composting, a stream is too wet, and no water drops is too dry.

Since you described a 3ft x 3ft x 3ft bin, are you aiming for hot composting as the means to kill pathogens?

Here's my observations after having successfully kept and started humanure compost piles through winters down to about -50F including wind chill:

I've found it helpful to wait until I have about 7 buckets collected at a time. When starting out a new bin it helps to keep the toilet material located in a pile rather than spread out across the entire bin. A pile 3ft x 3ft x 3ft will heat up much better than the same contents spread out 4ft x 4ft x 1.7ft. I start with up to 1.5ft deep of bad hay on the ground and build my pile on top of that, then add another foot of bad hay on top.

I build the next pile (after collecting another 7 buckets) leaning against the first, and repeat until eventually there is enough cooked material to keep the full width of the bin hot.  New additions of 7 buckets after that are added into a depression made into the center of the cooked materials, ideally even covering the new material with a bit of the recently cooked material for added insulation.

I mostly use kiln dried pine for toilet cover material, but add animal manure and/or spent hay to boost temperature. To keep the temperature hot I find it helpful to ensure I fully hydrate the animal manure and spent hay. My rule of thumb for the toilet bucket is to cover poo and pools, and try to use just enough toilet cover material that by the time you've collected however many buckets you choose the sawdust in the top of of each is hydrated (not dry or pooling).

Cristobal Cristo wrote:The mushrooms that we know and want to eat grow when it's warm and wet, but on my property when it's wet it's too cold and when it's warm enough it is completely dry.

I've found some success in Colorado using microclimates.  Oyster pegs in fresh aspen logs left to myceliate under shade cloth close enough to the yard to get overshoot from the sprinklers for a year, then mostly buried in the dirt and mulch as contour edges where the sprinklers could reach.  Wild Oyster spores on aspen stumps near rain gutters with no irrigation.  Garden Giant spawn mixed in with manure and wood chips around a tree at the edge of the irrigated lawn.  Spreading wild Shaggy Parasol mushrooms in a small grove of trees and shrubs with no irrigation.

I've had plenty of failures as well.  I have a long way to go, more experimenting and research to figure out the right microclimates for the kinds I want to grow at our new place.

Julie Baghaoui wrote:Can we wash our gray water through the worm tank too (mainly Plain soaps for dishes clothes and washing) or will this be too much water passage ? Family of four plus visitors …

Julie, as I've researched this question for my own use I've found that Wendy's vermicompostingtoilets.net and Dean's vermifilter.com open source designs both mention that you can send greywater through.  Having said that, the scientific papers on "vermifilters" show that the effectiveness works fantastic on the scale of flush toilets but starts to drop off as you get larger greywater surges like draining a bath tub.  For example this article indicates performance drops with a Hydraulic Loading Rate greater than 2.5m^3 influent per m^2 surface area of the vermifilter per day.  In light of that it is interesting to note that Wendy's design outputs subsurface but within the top soil (more microbial cleaning that subsoil) while Dean's surface irrigation approach use a series of vermifilters to allow you to clean to whatever level is needed.  Alternatively you can increase the surface area of the vermifilter.

Since our code has less restrictions on the reuse of cleaned greywater our current plan is to run the greywater through a separate vermifilter from the blackwater, and then recirculate it through a secondary vermifilter using one of Dean's designs to achieve the desired level of treatment.  That will allow us to reuse the greywater for surface and subsurface irrigation of animal crops (unrestricted) and crops for people (until 30days prior to harvesting).

John Bos wrote:I'm wondering if an indoor compost toilet can be without foul odors? If so, is this only possible with lower temperatures? Any ideas / advice?

John, I would agree that with enough of the right kind of cover material a compost toilet does not stink, assuming you're talking about the simple Joe Jenkins 5 gallon bucket method.  It can be used on the second story without modifying the house, assuming you can carry the buckets and have a plan for where and how you'll compost it.  Do your local regulations have any constraints?

Given the age of the home, are you on a septic, and do you know if it is still operating safely?  There are many types of ecological options, including flush designs, including commercial and DIY, that may be worth looking into depending on your goals, local regulations, and your preferences.  Any additional insights might help us help you better.

Rebecca Norman wrote:The cover material was sawdust mixed with coffee grounds and crumbled leaves. Pure sawdust that I'd used in previous years came through the 2-year process unscathed, so now I try to mix it with coffee grounds and/or leaves and water the mix to pre-compost before use.

Rebecca, thanks for sharing! How hot did your pile get when the sawdust came through the heating phase unscathed?

I'm also trying to work through my Joe Jenkins sawdust coming through unscathed.  In rereading Joe's books I realized I was keeping my piles too hot, so I'm now targeting a cooler temperature to promote a wider range of microbes.

Barbara Kochan wrote:Does Joe's book address pharmaceuticals in humanure??.... What about urine and pharmaceuticals?

Chapter 10 of Joe Jenkin's The Compost Toilet Handbook covers what is known about composting pharmaceuticals and Heavy Metals.  In short there is some benefit for the things that have been tested but it is not a sure treatment for it.