I spent the afternoon going through old posts on here, but can't find an answer to my question. I recently moved to a place where the compost loo idea has been started but not been thought through. The result are 3 wheely bins full of poo. No sawdust or anything with it, just poo. Now I am trying to come up with a solution. My plan is to shovel empty the bins and build one big compost pile. Loads of straw on the bottom and then layer poo and sawdust. Close the pile with more straw, wet it with grey water and let it do it's thing.
Is there anything I should think of as it is 'old' poo?
It seems straight forward what I have to do. Just want to make sure its not going to end in a disaster as it is my first attempt.
Thanks for any advise!
People use the sawdust when using humanure systems for several reasons: One of these is because it's easy to scoop onto the deposit. It is also used because it absorbs moisture. The primary purpose, beyond those, is to add carbon. Because poo lands in little uneven piles which can topple in time, and these get dusted with coverings of sawdust, there are bound to be air pockets when sawdust is added with every deposit. Sawdust is otherwise potentially a bit too fine for regular compost making, as it does not add the air to the system very well unless something else that does add air (like straw) is added. If you are planning to do a 'build it and leave it system' (rather than a turn it in a week type system), then you want some air-space in the pile. Does that make sense?
When you have an outhouse, or pit toilet, or an improperly done humanure system (where the poo has not been mixed with any carbon source-as seems to be your case), then you have very little air, and so your "old poo" is bound to be quite dense and probably anaerobic. Bad bacteria tend to thrive in such anaerobic conditions unless you are culturing things properly (like bokashi).
I think your plan, the way you are describing it, should work, but I would amend your formula somewhat. I would ensure that the poo material is broken apart (to make sure that the anaerobic bacterial colonies are taken over by aerobic systems) and mixed well with your carbon sources, particularly your sawdust. One way to do this is to do the mixing in a wheelbarrow and chopping it with a hoe. I would think that having straw under the system, as you describe, will help to give some air to it, but you might want to add some straw to your pile itself, instead of just sawdust. The straw can be a pain in the butt to chop up and mix, so just use the sawdust to work in while mixing in the wheelbarrow with the hoe. The straw can be added when you create the piles. It will add more air spaces, and thus give you a much better chance of generating aerobic conditions. Ensure that the pile is an even damp consistency (this is generally done throughout the pile layering process), but is not wet. It should have a sheen of dampness, not be saturated at all. The pile will collapse on itself after an initial hot phase that peaks a few days after building, and it will then become fairly dense again, but cooler. If you have compost worms, when you build the pile add some to the bottom or sides (where it doesn't get nearly as hot (and they will multiply and take over the pile to not only finish the job but also to add air holes throughout the pile). These air holes further the aerobic process, increases it's internal surface area, and allow for a larger diversity of microbes to have a habitat niche.
Be very cautious about handling this raw poo material. Use rubber gloves, and hose off and scrub any of your tools that come into contact with it.
Best of luck.
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Thank you for your advise. I managed meanwhile to sort out the freshest bin. And I did it as recommended with loads of sawdust mixed in and layered like a lasagna with dry bracken since I have loads of that. Looks good and doesnt smell. I havent gathered the courage for the other bins. They are due asap though.