Vermicomposting system for community toilets (Rich Earth Institute, Vermont, USA)

  • Benno
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Composting system for community toilets

Hi Bogdan and Dean … We use a urine separating batch system that collects the solid contributions in either a 17 gallon / 65 liter or 25 gallon / 95 liter rectangular bin. When this bin fills, we decant it into a larger sequestering bin that has been adapted to have a vented false floor to maintain aerobic conditions at all depths. Because the urine has been diverted, worms can be added to this bin. As the bin fills, the worms will work their way up the pile as material is added. The more users, the greater number of sequestering bins will be required to achieve adequate composting time, or the sea bins can be scaled up. The urine is processed for use as fertilizer either by composting in a high carbon medium, or according to protocols established by these folks: richearthinstitute.org

Seq bin composting allows for continuous zero-discharge use for unlimited amounts of users as long as you have enough sequestering bins on hand to process the contributions. As each bin finishes, the majority of the worms are at the top of the pile. These can be collected to start additional seq bins. The seq bins I use are 96 gallon / 365 liter sealed trash bins. (This product works well - www.toter.com/assets/documents/products/...16_V2_Reverified.pdf )

Dean - I wasn’t sure you were recommending starting with a handful of worms for the volume Bogdan is considering. Even though worms double their population in 60-90 days in optimum conditions, that seems like quite a small amount to start with in order to reach optimum population for the task. And at the risk of stating the obvious, the species of worm is important too. The go-to species for decomposition is the Red Wiggler (Eisenia Foetida).

The two pictures are of a 300 member community garden composting privy with bin storage in rear, and one of the urine composting bins. This site does not compost with worms because of freezing temperatures for much of the year would jeopardize the worm population, but the urine diverting setup will allow for it.

Ben
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  • BPopov
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Re: Composting system for community toilets

Hi Ben!

Thanks for sharing your practical experience!

Do you think that 95 l bins used for collection are too small for vermicomposting right in them witout decanting to the bigger bin?

Could you please share what kind of urine separtion interface do you have?

Best,

Bogdan

Bogdan Popov
The Ecosolutions Forge
www.ecoforge.org
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  • Benno
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Re: Composting system for community toilets

HI Bogdan …

We have traditionally used the Separett Privy Seat for diverting. It is easy to set up, and except for the rare occasion, it is welcoming of all anatomies. They even supply a child’s seat. www.separett.com/products/accessories/privy-501/ . They makes a foam seat version for cold climates - Model 500. Separett also manufactures a series of UD commodes that resemble more conventional toilets if your needs are more formal. There will likely be a learning curve associated with keeping sawdust and shavings out of the urine funnel. A set of tongs nearby will be useful. We only put the TP used for poo in the bin. The pee paper is disposed of. If it is available, unbleached TP is recommended.

Yes, you should be able to use the smaller collection bins directly for vermicomposting, I make worm bins for home and classroom composting out of the same tote bin I use in the privies. These: www.homedepot.com/p/HDX-27-Gal-Storage-T...7GONLINE-5/205978361

This is my embarrassingly antiquated website, typos and all, if you want to see a similar but much older version. wehaveworms.com

I modify the totes with a sealed reservoir to manage excess liquid. I also place 2” aluminum screened vents along the top edge and in the lid. I also add a spigot which remains open to keep the lower portion of the pile aerobic and to drain away any leachate. Once the bins fills, it can be set aside to compost. Good idea to date the bins. Be sure to keep the bins out of the rain and protected from overheating or freezing the worms.

To create the reservoir, I use 2” foam billets pinned with stainless steel nails to a piece of polyethylene lattice to prevent shifting. Then I use waterproof tape such as “Sika” or “Eternabond” roofing repair tape, or “Siga” waterproof membrane tape, to fasten a piece of non-biodegradable landscape fabric over the lattice and to the walls of the bin. This prevents the worms from entering the reservoir and drowning. Because of the urine diversion, you may not have the same liquid issues with the humanure compost as with food scraps, but the benefit of aerobic stabilizing is helpful. It’s also useful to add some grit material for the worms to “chew” with, I save eggshells which I crush to a fine sand consistency. A blender works great for that. About a 1/4 liter per bin. A liter or so of mature compost will add some microorganism diversity. We use sawdust and pine shavings to “flush”, which also promotes mycelial growth. Be sure to use a wood species that will easily decompose.

I use a non-vinyl, non-metallic spigot like this. www.redwhitevalvecorp.com/product/rw-302pp-poly-hose-bibb/ .

And a bulkhead fitting similar to this to make the through-wall connection. barndoorag.com/greenleaf-bulkhead-fittin...zEAQYAiABEgIu0fD_BwE

But having said all that, if you are trying to manage a large volume, we found it is much more practical to use the larger sequestering vessels to co-mingle the contributions. There’s much less material handling.

Sounds like an interesting project you are working on. Wishing you success.

Ben
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  • Benno
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Re: Composting system for community toilets

Hi Kris …BSF larva will work great and are voracious feeders, although, IMO, there is a bit of a yuk factor to them them that can take some getting used to, which is probably why they changed their name to BSFLs instead of maggots. I guess probably no different than the yuk factor of composting humanure, which we seem to have now come to love. As Dean mentions, they are a great protein source and chickens enjoy them tremendously. Possibly would be the same for certain fish farming.

I do not have a lot of experience with BSFLs, other than when they volunteer in the worm bins. They can tolerate anaerobic conditions better then worms. As I understand, managing them in the bins denies them the pathway to maturing into the fly. I’m not clear on the science of this, but will review.

I want to hear more about your work with WASH if you want to go off line. This email address is being protected from spambots. You need JavaScript enabled to view it.

What is your experience with them?

Best … Ben
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  • Benno
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Re: Composting system for community toilets

Kris ... I meant what is your experience with BSFLs, not WASH.
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  • BPopov
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Re: Composting system for community toilets

Hi Ben!

Thanks for sharing!

Maybe I didn't properly understand the construction of the the reservoir. Do you mean you create an aerated basket inside the tote made of plastic lattice and then have some kind of ventilated fabric taped to it?

"To create the reservoir, I use 2” foam billets pinned with stainless steel nails to a piece of polyethylene lattice to prevent shifting. Then I use waterproof tape such as “Sika” or “Eternabond” roofing repair tape, or “Siga” waterproof membrane tape, to fasten a piece of non-biodegradable landscape fabric over the lattice and to the walls of the bin."

Best,

Bogdan

Bogdan Popov
The Ecosolutions Forge
www.ecoforge.org
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  • muench
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Re: Composting system for community toilets

Just a small note to explain why I have moved Ben's post into this separate thread (it used to be in one of the vermifilter threads). Dean explained it to me like this:

++++++++

Hi Elisabeth, just to explain, Ben is practicing vermicomposting of feces (the same process as vermicomposting of kitchen waste etc), whereas vermifiltration is a wet composting process where there is a substantial volume of water both entering and exiting the system or digester. These need to be differentiated because they are very different processes.

+++++++

(by the way, for anyone new to the concept of vermifilters, check out the Wikipedia article on vermifilters which Dean and others wrote:
en.wikipedia.org/wiki/Vermifilter )

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