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Humanure flushing toilets and worm farms  RSS feed

 
Rebecca Norman
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Location: Ladakh, Indian Himalayas at 10,500 feet, zone 5
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food preservation greening the desert solar trees
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Yes, of course, I'll correct that to Black Dog. And read the website more thoroughly. And I've got both her books now so I'll read those.
 
Feidhlim Harty
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Hi Chris, Wendy and Rebecca et al, I'm finding this conversation very interesting. I'm currently proposing a version of this system in Ireland for a tourism application. There will be 12 accommodation units. What I'm designing at present is three Brownfilter boxes essentially as per the Solviva approach; three Aquatron units with integrated chambers; and three IBC tanks essentially as per your photographs in PM Wendy.

Chris, do you have any results of monitoring from your system?

Sean, I'm not aware off hand of any systems in the UK, but you're probably like me insofar as the extra liquid certainly isn't necessary in the garden. In my case the main hurdle will be convincing the local authorities that our approach is not going to damage the local environment; which essentially means that all effluent will need to be disposed of safely on heavy, rocky soil. In this instance we propose a pump-fed drip irrigation system. Not entirely in line with Permaculture principles, but a compromise to both address pollution concerns and to deal practically with extra liquid in a wet environment.
 
Wyatt Barnes
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Certainly to prove a system you might have to do more than necessary at first, hopefully the extras aren't costly and can be either removed or ignored after testing. I would argue that a closely monitored system could be as exotic and odd as desired without damage to the ecosystem. Worst case scenario has you modifying or changing as needed.
 
Feidhlim Harty
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The main issue for us Wyatt will be to get the water into the soil… There is a thin peat soil over rock, so disposal is the issue - regardless of how clean it may be. What I want to do here is to use the source separation technologies so that at least we an recoup carbonaceous biomass and nutrients from the system rather than just use electricity to waste these away into the air; and then dispose of it in a way that is likely to get through the planning process.
 
Wyatt Barnes
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Thin soil is a common problem in my area. Lots of our land is just bedrock with a couple of inches of rotted leaves and moss on it. In cases like that man made mounds are used to create weeping beds. I hope you get something passed, here if it mimics a traditional system or appears to be a mini sewage treatment system they love it. Not so much if it just works well.
 
Feidhlim Harty
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Sounds much the same then…
 
Sean Kettle
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Feidhlim Harty wrote:
Sean, I'm not aware off hand of any systems in the UK, but you're probably like me insofar as the extra liquid certainly isn't necessary in the garden. In my case the main hurdle will be convincing the local authorities that our approach is not going to damage the local environment; which essentially means that all effluent will need to be disposed of safely on heavy, rocky soil. In this instance we propose a pump-fed drip irrigation system. Not entirely in line with Permaculture principles, but a compromise to both address pollution concerns and to deal practically with extra liquid in a wet environment.


Best of luck Feidhlim! For our potential build - we're not allowed to discharge any effluent on the land, save for anything "chemically inert". I've been assured outflow from a reed bed would satisfy this, could that be a solution for you? I've been looking at these ready-made tanks that can be linked up.

One thing I'm unsure of with these - surely they overflow if it rains? I'm considering placing it in a greenhouse for this reason...
 
Feidhlim Harty
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Thanks Sean, Second thing first: if it rains, the water will simply add to the overall volume of effluent from your mini reed bed, so no problem there, and no need for it to go in a greenhouse. The Irish wastewater codes call for a minimum of 5m2 per person capacity in the house. Thus for a 3 bedroom house, the equivalent is 5 persons, thus 25m2 minimum reed bed size for secondary treatment (reducing the BOD and suspended solids from 300 to c.20mg/l). An additional 1m2/pe is needed for tertiary treatment to achieve 5-10mg/litre. Clean river water has a BOD of about 1mg/litre.

Vis a vis your suggestion: reed bed and constructed wetland design is my day job, and yes, they are certainly an option for secondary treatment the site in question. The challenges here are twofold, (1) what's the best way to get humanure from a flush toilet infrastructure so that I can recoup nutrients and biomass while still having the ease of use at the flushing end, and (2) how to actually get the water into the soil when it's been treated.

The humanure options at present are a Swedish Aquatron unit and some variation on the Solviva brownfilter system. The disposal to soil option is currently a pressure distribution system. Whether we need a reed bed between the two is currently open to debate. The plus side is that it would filter more nutrients out. The down side is that it may be an unnecessary expense and energy input when there are perfectly good oak trees aplenty that would probably love those extra nutrients from the pressure distribution system.
 
Sean Kettle
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Feidhlim Harty wrote:Thanks Sean, Second thing first: if it rains, the water will simply add to the overall volume of effluent from your mini reed bed, so no problem there, and no need for it to go in a greenhouse. The Irish wastewater codes call for a minimum of 5m2 per person capacity in the house. Thus for a 3 bedroom house, the equivalent is 5 persons, thus 25m2 minimum reed bed size for secondary treatment (reducing the BOD and suspended solids from 300 to c.20mg/l). An additional 1m2/pe is needed for tertiary treatment to achieve 5-10mg/litre. Clean river water has a BOD of about 1mg/litre.


Thanks for clearing that up Feidhlim. Sounds like a great day job

I'm also interested in making use of the nutrients in such a system. I've been speculating here about hooking up to an aquaponic system. Solviva tank - reed bed - fish tanks in an aquaponic system. Harvesting the mass from the reed beds to feed to worms/back soldier fly etc for the fish. I might be trying to run before I can walk here
 
Feidhlim Harty
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Hi Sean, perhaps the easiest way to recoup the nutrients is to use two Solviva brownfilter boxes in series followed by the Solviva green filter planted with a crop of comfrey for nutrient cycling back to your compost heap or willow or ash etc. for a quick growing firewood crop. Easier than aquaponics (but if you'd rather the watery route, then not necessarily as much fun to experiment with either).
 
Sean Kettle
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Feidhlim Harty wrote:Hi Sean, perhaps the easiest way to recoup the nutrients is to use two Solviva brownfilter boxes in series followed by the Solviva green filter planted with a crop of comfrey for nutrient cycling back to your compost heap or willow or ash etc. for a quick growing firewood crop. Easier than aquaponics (but if you'd rather the watery route, then not necessarily as much fun to experiment with either).


Aye that's a much neater solution. I'm running an aquaponic system at the moment and envision having one in this fictional future home of mine, hence the interest
 
Feidhlim Harty
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Well happy building Sean,

 
Andrew Ray
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It is winter and my wife has reminded me that when it is warm again I was wanting to make her the new bathroom with flushing toilet and so I'd better finally figure out what I'll do. Some of our friends got some sort of multi-chamber, aerated self-contained mechanical treatment unit. They said that the water coming out from it appears clean, and that dogs and birds drink it in the summer (which, given what all my dog has drunk and eaten, I'm not sure is such great testimony!). We were tempted by that, though it costs 1000€, but the manufacturer doesn't actually state how much electricity is used by the airpump blower, and it seems a waste that all the nutrients in the water are just used up by bacteria in the unit instead of being used by some plants, what I like about the saw dust toilet.

Reading through some of the replies, and just thinking about it, seems that perhaps this brown-filter / worm bin can be located underground? We don't ever have frosts going very deep into the ground-- our water line is buried just 30cm deep at some points without a problem, so it seems this could be a solution for keeping worms alive.

Reading that these brown filters were used at a restaurant, I wonder if any of you have experience with what sort of cleaning agents the worms will tolerate. We use liquid dish soap (though an "eco" brand), homemade washing machine powder, and previously commercial dishwasher powder, but now we've started using just sodium percarbonate for the dishwasher. The homemade washing powder is-- soap, sodium carbonate (washing soda), sodium percarbonate (which breaks down to sodium carbonate and hydrogen peroxide, the latter probably breaking down to O2 and H2O before leaving the washing machine), and sodium bicarbonate (baking soda). Showering ourselves is just plain soap, and baking soda and vinegar for hair. Would any of these things harm the earth worms, given that they'd be diluted with water?

I would prefer to deal with the graywater and blackwater together, though now that I think about it, I could perhaps run a separate pipe for the toilet and bypass the worm bin for all of the graywater.

In either event both waters need to go up a hill away from our house because I don't have room for them near the house, though I realize now that I could locate the worm bin in the ground in the tiny front yard, but after that things need to be pumped away.

The main advantage I'm seeing with the worm bin, but I want to verify, is that the effluent flowing from it is just a liquid. Because the pump for pumping water is 300€ new and can be found for less used, but the one for pumping sewage (which is the same, but with an additional cutting blade) is 800€ new and no-one seems to be selling used ones. If the worm bin never really needs emptying, then I guess I could just bury an IBC container in the ground, and provide a pipe for ventilation to it.

The end result of the system would be either way going up into our field, either to the constructed wetland system or else (if worm bin first) to just a swale with a lot of willows and other fast growing trees for firewood.
 
Wendy Howard
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Location: Central Portugal, Zone 9
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Hi Andrew.

The worms will tolerate a wide range of household chemicals. Anna Edey deliberately subjected hers to the 'normal' range of cleaners, not 'eco' brands, to see what would happen and the Black Dog Tavern was using the full range of commercial kitchen cleaners also. The worms were fine, even with drain cleaner! And this has been confirmed elsewhere. Check out this study for instance.

Yes, you could bury the tank. You just need easy access for topping up with the necessary organic carbon every so often and you'd maybe need to insulate the top of the tank and provide some sort of drainage so there was no risk of the tank being inundated in a heavy rain storm.

Yes, it's only liquid that comes out of the tank. The more depth of vermicompost you build up in the tank, the cleaner the water exiting the tank becomes. It might be worth taking the laundry water through the tank since it's laundry soap and fluff which, according to Art Ludwig, causes the greatest problems in grey water systems, but I don't have any personal experience of doing that. My system is black water plus wash hand basin only.
 
Feidhlim Harty
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Hi Andrew, just to add briefly to Wendy's comments: you mentioned a mechanical aerated system. There are a number of different types - each with different electricity input requirements. Overall the costs vary from about €90 to €140 per year for electricity costs alone for the standard aerated systems. Up to €275 for membrane batch reactors and down to about €23 for media filter units (pump fed systems over a media of rock wool or peat). These figures are for a 5-person system. There is a good graph of costs in Figure 4 here: www.epa-pictaural.com/media/wwater12/paper/donataDubber.pdf

That's just by way of some background info. Best of luck with your Solviva approach.

Interesting paper Wendy. I'm looking forward to looking at it in a bit more detail.
 
Andrew Ray
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Thanks for all this insight. I just have a few more questions, and then I'm going to gather materials and as soon as the weather gets good, start digging!

Do the worms have a preference or aversion to certain species of trees as far as to what I could source for organic matter? Fresh sawdust from a lumber mill is something I already get for the sawdust toilet and to put under the chickens. If sawdust is problematic (since I see mention of "wood chips" and "wood shavings" but not sawdust), this could be the excuse to get a limb shredder. We have a fairly unlimited supply of brush on our property, and if I ran out and started clearing overgrowth on other peoples' land, they wouldn't complain.

Is there a risk of the outlet of the IBC container getting clogged? Should I be putting gravel in the bottom to keep solids from migrating out?

As far as getting air to the worms, I am imagining a pipe extending up along the side of the house to roof level from the top of the IBC container to allow air to exchange, though maybe I would need also an input for air?

Since no one reports needing to remove compost, I plan to just leave the top of the IBC container as is with the large screw cap that comes on them.

The great thing I realized last night is that the pump doesn't have to be submersible, unlike what I have in my well. And I already have an above ground pump that someone gave me which just needs a bit of refurbishment. The secondary container that liquids would drain to would be sized to accommodate at least a half day of water usage here and set up with some electric level sensor. There is a two hour window in the early afternoon and 6 hour window overnight where the electricity is cheaper, so I would set it to automatically pump whatever is in the container at those times and only pump outside those times if the container fills completely.

What species of worms do y'all use for your worm-tanks? Is there some mail order company that ships them? I've never bought worms! Or are ordinary earthworms fine?
wormfarm.png
[Thumbnail for wormfarm.png]
Shoddy, semi-3d depiction of what I imagine
 
Wendy Howard
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Andrew Ray wrote:Do the worms have a preference or aversion to certain species of trees as far as to what I could source for organic matter? Fresh sawdust from a lumber mill is something I already get for the sawdust toilet and to put under the chickens. If sawdust is problematic (since I see mention of "wood chips" and "wood shavings" but not sawdust), this could be the excuse to get a limb shredder. We have a fairly unlimited supply of brush on our property, and if I ran out and started clearing overgrowth on other peoples' land, they wouldn't complain.


Do NOT use sawdust!! It's too fine. It will clog your outlet and drown your worms. The 'brown filter' material needs to be bulky with LOTS of air spaces incorporated into it. Variety is good - this is why I mentioned wood shavings + dead bracken + dead leaves. If you also have a variety of different woods going through your shredder, so much the better. I've no idea if there are woods the worms don't like, but with sufficient variety I doubt there would be any problem.

Is there a risk of the outlet of the IBC container getting clogged? Should I be putting gravel in the bottom to keep solids from migrating out?


There is if your material is too fine. Not if it isn't. You need a mesh of some sort over the outlet to hold back the wood shavings, leaves, etc. Faecal solids won't get anywhere near the outlet. Gravel isn't necessary, but neither will a few handfuls behind the mesh do any harm provided it's coarse enough not to slow down the water exiting the tank. You don't need gravel in the bottom of the tank.

As far as getting air to the worms, I am imagining a pipe extending up along the side of the house to roof level from the top of the IBC container to allow air to exchange, though maybe I would need also an input for air?


It's only really necessary if your tank is airtight. Worms live underground. There isn't a lot of fresh air down there. So long as there's the possibility of some air exchange, they should be OK.

Since no one reports needing to remove compost, I plan to just leave the top of the IBC container as is with the large screw cap that comes on them.


You need access to the tank to refill with wood shavings/bracken/dead leaves every 4-6 months. It would be a major pain to have to try and feed all this through the central hole, so you're best to cut away at least part of the top of the tank for better access. Your waste pipe is also best emptying into the centre of the tank, otherwise you massively reduce the tank's efficiency and end up with most of the activity to one side, so pipe it in through that central hole. Details of my system are here. I don't know how close the water table is to the surface on your property or what your climate is like? My concerns with burying the tank would be the potential for rainwater getting in during big storms or the tank floating up out of the ground if the ground gets saturated. The 'brown filter' material isn't very dense so it's not like a septic tank which will stay buried because of the weight of water in it.

What species of worms do y'all use for your worm-tanks? Is there some mail order company that ships them? I've never bought worms! Or are ordinary earthworms fine?


Red wrigglers or tiger worms - Eisenia foetida. I imagine you can get them mail order. Or if you have friends with horses, you'll find them in the piles of stable cleanings.
 
Andrew Ray
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Climate is, during the winter cold, occasionally bitterly cold, but usually -5 to -15 for the worst stretch, this year perhaps two weeks like that really. Now, for instance, everything melted and it was +8C today. We do get sometimes a lot of rain, but the soil is also heavy clay, so I would say it doesn't quickly saturate that quickly. The real challenge I have is just location. The only "downhill" from the house is the front yard, which is 4 meters between the house and the creek in front. It is also only 10 meters wide. (Why my wife's grandparents decided back in the 50's, when building this place, to put it so close to the front of the property, except that everyone else in the village has their houses the same way. Maybe it was to get a "city" like feel? The creek is just two meters wide, so our front rooms are just 6 meters from the road! Behind the house there is a good 50 meters to where a steep slope up starts.) But, due to drainage, the only water during storms ending up in the front yard is just from the rain that falls there. Well, I can't say 100% that it wouldn't try to float up, so I guess I could concrete some lengths of chain into the ground and tie it down with that.

This is also why I am inclined to suffer putting the wood chips through the hole on the top, though I hope to luck-out and find an IBC container with a 22cm lid instead of the more common 15cm. Aesthetically, the less visible disruption to the surface, the better. I imagined leading the pipe in through a hole in the side at the top, and extending it to the center. The picture on your website is good though, showing how the plastic cut-out gets clamped back with the metal part of the cage. In any event, I'll get my hands on an IBC container and get a better idea whether my idea would even work or not.
 
Wendy Howard
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That doesn't make things easy! I would be concerned about the height of the water table during wet periods if you're so close to a creek and on clay. I don't suppose you have a basement then for the same reason? Any kind of room below the toilet that isn't being used for accommodation? Here in Portugal the ground floor of buildings is always garaging, food storage space, winemaking, etc, sometimes animal accommodation, with the living quarters above, so the option always exists to use some of this space for a worm tank. It doesn't smell at all (provided all is working as it should be), so there's no real health and safety reason not to do this. Absent that, is there a possibility you can move the toilet to a higher floor and have the worm bin in an insulated enclosure against an outside wall?
 
Caleb Rae
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Location: Tennessee, Zone 6b
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Have been using a vermicomposting toilet for little better than 4 years now, currently in it's third incarnation. The original collection box I built after reading Anna Edey's book and quickly discovered that I had not built a waterproof collection vessel. A fair amount of effluent went out the pipe as desired, but it also leaked from every seam below water level. After several months I dug the box out, lined it with plastic, and refilled. This still leaked a little, but not nearly as badly. However, by last summer the box itself was showing signs of rotting, so I decided it was time for another revision. This Fall I used an IBC (275 gallon plastic container), lined the bottom with gravel and filled it with sawdust (what I had readily available). This worked well for a few weeks, then all the worms downed. My collection tank has never overflowed, but the water doesn't drain nearly as quickly as it needs to. As with many other projections, the learning continues. Some lessons thus far:
1) the plastic container with thread outlet and valve was a huge improvement over building a box and trying to make it waterproof, then figure out how to connect pipe to it.
2) as noted earlier on this thread by Wendy (wish I had read this a few months ago) sawdust is too fine. It will saturate, then drain far too slowly and drown your worms, leaving you with a stinky mess.
3) In my first and second attempts I used much coarser material (leaves, waste straw, wood chips) and results were much closer to what was described in Anna Edey's book.
4) This system is much more user friendly than either the self contained composting toilet we tried initially, and the bucket system we used between the 2nd and 3rd attempts. We have frequent visitors and Woofers from all backgrounds, and some people are very uncomfortable with toilet alternatives. I am fairly ambivalent to adults that express distress over a bucket of sawdust in a nicely built box with a lid and traditional seat, but I really did feel bad for my friend's 4 year old daughter that was in tears over it not being a "proper" toilet. The vermicomposting system avoids these issues, and unless it comes up, most people don't realize we don't have a standard septic system.
5) As the person responsible for cleaning and emptying the self contained composter and bucket system I am also a big fan of this system. The bucket system was much easier to deal with, but was still one more chore to add to a list that is already long enough.

We get occasional temperatures in -5 F range in winter and so far the worms have gotten through just fine. Originally I was concerned about what to plant in the filter beds, but they pretty quickly vegetated themselves with thinks that didn't mind cold temperatures. Natures hates to see nutrients wasted.
 
Andrew Ray
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Photos of our front yard site, shredded wood: https://goo.gl/photos/SPduYheq3vSuBxaeA

I got a used garden shredder on Tuesday for a good deal in the online ads. I hope the output from it is suitable for worms.

Wendy--

Well, it just rained all day yesterday, and I figured I should go just take a dig in the front yard, so see how the soil there really is after the rain. I think I mistated about it being heavy clay. Up in our fields it certainly is, but down here near the creek it has much more organic matter at least, and while the soil is moist it isn't "soggy".

Another thing I remembered is that, two years ago, I was testing how quickly our well would empty when being pumped out. I put the house around the tree in the photo (the well is just behind the small fence in the linked photos-- it is common with our neighbor). After a bit, I noticed an increase in dripping inside the well shaft, so I think the soil actually drains well.

For what it is worth, the water level in the well is 8 meters below the surface, even now after we had a lot of rain and snow melting.

We only have one floor right now. We plan to add another floor, but that is a down-the-road plan. I think one newer house on this side of the road might have a basement, but these older ones don't. In fact, none of the older ones have a basement, though some that are built into a slope have the root cellar under the house. I'm not sure if the reason for a lack of a basement is risk of it flooding or just the state of architecture post WWII rural Slovakia.

There isn't really room anywhere except at the back of the house to locate the worm bin above ground. One side of our house sits on the property line, the other has the path leading from the front to our entrance doors on the side and then there is the front as shown in the photos.

Therefore I'm just going to try putting it in the front yard. If it does try to float out, then we can dig down further and put a half cubic meter of concrete to anchor at the bottom.

Caleb--

Except when it is rainy and muddy outside and the toilet gets full, it is OK, though usually it is a chore that gets put off until the bucket is full. There is now about 2 cubic meters of compost pile that isn't very rapidly decomposing as well. I hope it speeds up in the spring. A previous humanure pile did decompose most of the way, then the chickens got in to it and sped up the process... My mother doesn't like the system when she visits. Mostly I would be concerned with possible visitors who would be too weirded out. Our children's pediatrician and her brother want to visit us this spring, but I think she might be particularly grossed out by such an arrangement. We visited her and she has a nice modern home in a different village nearby. Since some of our other lifestyle choices are on the edge here-- not vaccinating, homeschooling-- neither are go-to-jail illegal, but there is risk of fines and other harassment-- so I'm thinking better not to push it with the toilets.
 
Caleb Rae
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Andrew-
It would mean digging up most of your yard, but looks like you have enough space to use your yard and the grass as your filterbed. Tricky part would be having the pipe shallow enough that the grass was filtering effluent without having the pipe freeze in the winter. The company in Australia that was the first mention I had seen of vermicomposting toilets sound like that's standard practice for how they set up the discharge. They may not have to worry about freezing issues, but something to consider. The "soil" on our farm is also very heavy clay (really mostly mix of table sized to pebble sized shale). When I built a raised bed and piped the discharge into it I always had a miniswamp at the downhill side of the bed. It didn't smell bad, but still made a mess of that part of the yard. When I was replumbing between the 2nd and 3rd attempts I lined a trench with gravel and piped into that, and covered it back to grade level with dirt, then seeded it.

Wendy-
Over the weekend I took out the Mark III and installed the Mark IV. Your pictures showing the flush pipe entering through the lid and recommendation that that makes better use of the whole chamber sounded like good suggestions. That rock work was beautiful, really nice way to finish it off. I didn't put any gravel in the bottom this time, just filled the tank with used bedding straw.
 
Sean Kettle
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Interesting commercial take on the system - with papers and research to back up its efficacy:

http://www.bearvalleyventures.com/#!tiger-2

Hope to visit this in the future and make a deposit!

http://blog.cat.org.uk/2012/02/07/new-toilet-for-worm-based-sanitation-project-launched/
 
Steve Smyth
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Thank you for sharing !!

This is some fantastic information!

I had looked at this idea a few years ago and could not find any DIY examples to give me confidence to try it myself. Fast forward two years: I was researching DIY composting toilets to replace my current system and stumbled across this thread. I am currently using grey water to water my yard with good success and I am storing black water onsite in a 300 gallon tank. I pay the local portable toilet company to come out and pump the tank every 3-4 months. At $125 a shot, I would sure love to reduce or eliminate the coast & hassle.

I am using a very low flow toilet (.5 liter/flush) that dumps into a 35 gallon tank. When this tank fills up I use a macerator pump to transfer the effluent to the larger tank. What I wind up with is a loose slurry.

I wonder if I could take an IBC tote and cut the top out and place drain rock in the bottom. Cover the drain rock with landscape fabric. Place a bale of straw in the center and surround it with bedding material (wood shavings/chips, shredded leaves & paper etc). Then pump 30+ gallons of effluent onto the straw bale every 10-14 days. Do you think this is a practical application?

My thought is that the straw bale would help disperse and moderate the effluent flow to avoid drowning the worms.

If the liquid discharge from the bottom of the IBC tote is clean enough I could pump it to a raised bed planter. If it is not suitable for that I would continue to store it and have the potty people come out and remove it as I am now just not nearly as often.

What do you all think?
 
Wendy Howard
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Steve Smyth wrote:I wonder if I could take an IBC tote and cut the top out and place drain rock in the bottom. Cover the drain rock with landscape fabric. Place a bale of straw in the center and surround it with bedding material (wood shavings/chips, shredded leaves & paper etc). Then pump 30+ gallons of effluent onto the straw bale every 10-14 days. Do you think this is a practical application?

My thought is that the straw bale would help disperse and moderate the effluent flow to avoid drowning the worms.

If the liquid discharge from the bottom of the IBC tote is clean enough I could pump it to a raised bed planter. If it is not suitable for that I would continue to store it and have the potty people come out and remove it as I am now just not nearly as often.

What do you all think?


I think you'd be better just to have the effluent go straight to the worm bin. By macerating it with the flush water, you're doing something which then has to be undone again. Better not to do it in the first place. From Anna Edey's figures, the vermicomposting ecosystem will clean the liquid component of the flushings in as little as 10 minutes and remove upwards of 90% of the dissolved nitrogen. The water can be filtered much more efficiently and effectively with a speedier throughput time if it's not been mixed up with the faeces and your system is much less likely to run the risk of becoming too wet for the health of the worms. Drain rock isn't necessary with this set-up either.

It's true worms are used very successfully to compost sewage sludge, but to my way of thinking, a system has greater resilience the closer it is to the way nature intended. Mammals were designed to poop on soil, not water, and worms evolved in the soil to deal with it. Poop + water = disease + smell, so if you're going to use water as a carrier medium, keep it as brief as possible! I think it would be very hard to avoid a stink with 30 gallons of sludge at a time. If there's no option but to do it the way you suggest, then I would feed your worms much smaller amounts much more frequently and fill the tank with a well mixed selection of carbon material, not one type in the middle and another at the edges. I wouldn't really think of it as 'bedding material' so much as feedstock - the whole lot will disappear in a surprisingly short period of time!
 
Steve Smyth
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Wendy Howard wrote:

I think you'd be better just to have the effluent go straight to the worm bin. By macerating it with the flush water, you're doing something which then has to be undone again. Better not to do it in the first place. From Anna Edey's figures, the vermicomposting ecosystem will clean the liquid component of the flushings in as little as 10 minutes and remove upwards of 90% of the dissolved nitrogen. The water can be filtered much more efficiently and effectively with a speedier throughput time if it's not been mixed up with the faeces and your system is much less likely to run the risk of becoming too wet for the health of the worms. Drain rock isn't necessary with this set-up either.

It's true worms are used very successfully to compost sewage sludge, but to my way of thinking, a system has greater resilience the closer it is to the way nature intended. Mammals were designed to poop on soil, not water, and worms evolved in the soil to deal with it. Poop + water = disease + smell, so if you're going to use water as a carrier medium, keep it as brief as possible! I think it would be very hard to avoid a stink with 30 gallons of sludge at a time. If there's no option but to do it the way you suggest, then I would feed your worms much smaller amounts much more frequently and fill the tank with a well mixed selection of carbon material, not one type in the middle and another at the edges. I wouldn't really think of it as 'bedding material' so much as feedstock - the whole lot will disappear in a surprisingly short period of time!


Thank you for the input.

Unfortunately the only way to have the effluent go straight into the worm bin would require moving the toilet to an outbuilding. I have actually considered that and brought it up for a vote at our family meeting. I lost 1000 votes to 1. I said yes & my Wife said no.....

I wonder how well it would play if I maintain my current setup and add an additional tote as a worm bed and use a pump on a timer to move 5 gallons of effluent from the 300 gallon tank into the worm bed every morning?

Thanks again

 
Feidhlim Harty
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Steve, a client of mine used a marine toilet, which had a combined pump and macerator built in, and then pumped directly to the woodchip bed. That seemed to work ok for him. However, Wendy's comments about flushing directly to the woodchips are very valid and you'll need to consider that in your overall design by factoring in an extra filter stage or equivalent to make sure that the final effluent is good and clean before discharge.
 
Steve Smyth
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Feidhlim Harty wrote:Steve, a client of mine used a marine toilet, which had a combined pump and macerator built in, and then pumped directly to the woodchip bed. That seemed to work ok for him. However, Wendy's comments about flushing directly to the woodchips are very valid and you'll need to consider that in your overall design by factoring in an extra filter stage or equivalent to make sure that the final effluent is good and clean before discharge.


The macerating marine toilet would yield a very similar output compared to what I am dealing with. I would like to hear more about your client's implementation and success.

As far as filtering goes, I was considering pumping the fluid that leaves the worm bed into a raised reed bed.
 
Feidhlim Harty
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Steve, the last I heard the client was very happy with that approach. Follow-up is sometimes thin on the ground though. Do you have guidelines for the reed bed design? Just be sure to build it large enough. One of the challenges is systems sized too small. That said, if you're using a vertical flow system then you'll need to be sure that the summer weather where you are won't fry everything in times of low inputs. My website has links to the Irish EPA Code of Practice (www.wetlandsystems.ie) if that's of any help to you. All the best with it.
 
Steve Smyth
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Feidhlim Harty wrote:Steve, the last I heard the client was very happy with that approach. Follow-up is sometimes thin on the ground though. Do you have guidelines for the reed bed design? Just be sure to build it large enough. One of the challenges is systems sized too small. That said, if you're using a vertical flow system then you'll need to be sure that the summer weather where you are won't fry everything in times of low inputs. My website has links to the Irish EPA Code of Practice (www.wetlandsystems.ie) if that's of any help to you. All the best with it.


Thank you.

I have been looking at reed bed design information but haven't gotten very far yet. I appreciate the tips.

Do you have any information regarding the time needed for any hazardous contents in the worm bed to break down to the point that the compost can be handled without health concerns?
 
Feidhlim Harty
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My understanding of vermicomposting of humanure is that coliforms and other faecal bacteria will show very effective die off, but that Ascaris (roundworm) will survive relatively unscathed by the experience and will presumably be subject to standard die off rates. This, rather unhelpfully, is "many months" in soil. Following is an excerpt from a planning report that I wrote a little while back, which may be of interest in this regard:


Storage for a particular timeframe is one of the methods proposed by dry toilet suppliers to offer good pathogen destruction. Sinha et al (2010) found that even a three month storage time provided adequate (99%) breakdown of the most tenacious pathogens for Vietnamese pit latrine contents. Likewise the USEPA cites similar timeframes. The table below (shown in the planning report, not included here) is taken from the USEPA Water Efficiency Technology Fact Sheet - Composting Toilets. What is interesting to note is that all pathogens listed have a lifetime in soil of <120 days with the exception of the eggs of the roundworm Ascaris lumbricoides, for which a somewhat less precise "many months" is cited. Thus even if humanure is not subjected to thermophilic composting or vermiculture, it will still be biologically safe after a period of "many months". It was proposed for this planning application that the compost be stored for 18 months as recommended by the toilet supplier, and this was subsequently increased to a 2 year storage time as selected by the homeowner. However, despite the USEPA table, other sources cite Ascaris egg survival time in soil as being up to 5 or 10 years(1), so while 99% of the population may die off after 3 months(2), the remaining 1% may potentially be a viable source of the parasite. Thus it is recommended that either thermophilic composting is adopted as the sterilisation method used, or stabilised vermicompost be buried at a depth of not closer than 300mm to groundwater (in like with (Irish) EPA effluent disposal guidelines for tertiary treated effluents). The use of humanure that has not been treated to controlled thermophilic composting is not recommended, and despite Jenkins' research to the contrary, as an additional factor of safety it should be dug into the soil on this site for non-food plants only.

Sinha RK1, Herat S, Bharambe G, Brahambhatt A. (2010) Vermistabilization of sewage sludge (biosolids) by earthworms: converting a potential biohazard destined for landfill disposal into a pathogen-free, nutritive and safe biofertilizer for farms. Waste Manag Res. Oct;28(10):872-81

(1) Roberts LS, JJ Janovy (2009) Foundations of Parasitology, Eight Edition. McGraw-Hill, USA and Murray, PR, KS Rosenthal, MA Pfaller (2005) Medical Microbiology, Fifth Edition. United States: Elsevier Mosby, 2005 cited in wikipedia - sources not verified; may well include zero or sub-zero factors, but included here to demonstrate the importance of a good vermicompost or thermophilic compost system to provide 100% egg mortality.

(2) Jensen PKM, PD Phuc, K Flemming, LT Klank and A Dalsgaard (2009) Survival of Ascaris eggs and hygienic quality of human excreta in Vietnamese composting latrines. Environ Health. 2009; 8: 57.


Hope that's of use in your researches.
 
Wendy Howard
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An alternative to a reed bed might be a second worm bin. Have you checked out Anna Edey's original work at all? There are some details here
. There are also test data on her systems here.

As far as the worm compost is concerned, Anna Edey has now had her composting toilet operating for over 20 years. To date, she's never had to empty it. I can't see mine filling up any time soon either. The more established the ecosystem becomes, the more efficient it gets. If the bin is managed with the aim of creating a self-sustaining ecosystem in this way, then problems of compost handling disappear.
 
Feidhlim Harty
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Good point Wendy. What is the next stage in your system? Do you send effluent on to water fruit trees? Have you any analysis to date to complement Anna Eday's results in her "Green Light at the End of the Tunnel" book.

Steve, Eday's book is well worth the read.
 
Wendy Howard
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It's a 'greenfilter' bed Feidhlim - basically a growing bed containing a large amount (about half a metre's depth) of the same coarse woody material used in the worm tank to act as an organic 'sponge', topped with soil and planted with a lemon tree (more plants will follow). The tank outflow is spread evenly across the bed through a network of perforated pipes laid in the woody layer. I used a lemon very deliberately to monitor just how much nitrogen makes it through the system as it's a heavy feeder and will show in leaf colouration and growth if its not getting enough nitrogen. It's doing OK, but neither does it look well fed, which says that very little nitrogen is making its way through the worm bin. Having said that though, it's only guests who use the toilet to urinate (I collect urine to feed my other citrus trees).

Aside from the lemon tree, I don't monitor the output of the system. It's black water only, so it's low volume. Last summer I even had to water the lemon tree. I will take some samples at some stage I'm sure, but at the moment there's far too many other projects needing attention and there's only one of me!
 
Steve Smyth
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Thank you both!!

I really appreciate the good information.

I had seen some of Anna Edey's information but the links you provided I had not seen before.

A second worm bin would certainly be a workable idea. Perhaps I could follow that with something resembling a reed bed. Some sort of isolated planter with some sort of water loving plants.

Another option I have been looking at is a sand filter. Recommendations that I have read indicate that 1.2sq. ft. of surface area per gallon/day of effluent. I currently produce about 3 gallons per day. If I were to feed that to the worm bed I would expect that the fluid output would be somewhat less. An IBC tote filled 30" deep with appropriate media would present over 12 sq. ft. of surface area. That should be adequate to help "polish" the output from the worm bed.

Good idea or bad: IBC tote based worm bed followed by a "hybrid" using another IC tote with 30" of sand topped with landscape fabric and then 10" of worm bed on top?

Another question: You warned against dumping the full 30 gallons into the worm bed in one shot. It makes sense to me that too much liquid at one time will drown the worms. Looking at the numbers I found that 30 gallons of fluid will fill the tote about 3.6 inches. How much do you think I could add in one shot without harming the worms?

Thank you all again.
 
Wendy Howard
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Personally I think a sand filter would be unnecessary. This is a living system and as such it behaves in a much more dynamic way than an inanimate filtration system. Yes, macerating the faecal solids with water is going to reduce efficiency somewhat, but two worm bins, especially the size of an IBC tote, should be more than adequate for a single household. Anna Edey used this technique successfully in processing septic tank outflow at the Black Dog Tavern.

The worm bin is very much more than a bunch of worms hanging about in some bedding material. It's an entire ecosystem. The coarse carbon material provides an almost infinite surface area for bacterial colonisation and is consumed in the process of stabilising the active nitrogen in the effluent. This is as much part of the cleaning system as the worms. With time, as I said, this becomes more and more efficient. The absolute key to the health and vitality of the system is that it's aerobic. The worms are central to this in that passing throughout the matrix, they keep the air channels open. This is why you don't want to be dumping large amounts of sludge onto the system. You run the risk of turning it anaerobic, whereupon the entire ecosystem collapses. Far better to have it on a continuous low-volume feed, which is how all the sludge-processing operations I've seen seem to work.
 
Steve Smyth
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Thank you Wendy,

I do understand that over-applying liquid will damage the worm bed. I, however, have no clue as to "how much is too much?".

As to the sand filter, it is not a "mechanical filter" it is also a living aerobic system. That said.. It does sound like simply running two worm beds in series would be simpler and suitably effective.

As the vision forms in my slow moving brain... I am seeing an IBC tote based first bed and a raised bed planter lined with pond liner and containing the second bed and some plants.
 
Wendy Howard
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That would work.

Rather than play with the "how much is too much" question, is there any way you can have a semi-continuous feed? Or maybe a twice daily dump? I would think you would be fairly safe with that?
 
Steve Smyth
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Unfortunately the 35 gallon tank that the toilet dumps into has to be fairly full before dumping or I run the risk of leaving solids behind. When that happens I wind up with a poo-pyramid in the tank directly below the toilet.

If I dump the 35 gallon tank into another container (55gallon drum?) then I could pump it (again) to the worm bed in small doses. I have access to a cycle timer that will run the pump for a few seconds every several (up to 120) minutes. Maybe 15 seconds every two hours? Unfortunately that starts to complicate things.
 
Steve Farmer
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Wendy Howard wrote:The coarse carbon material provides an almost infinite surface area for bacterial colonisation and is consumed in the process of stabilising the active nitrogen in the effluent. This is as much part of the cleaning system as the worms.


How about throwing a few flushable chunks of charcoal into the toilet every x number of flushes? Would this save the need to open the IBC and add straw etc, or would it just end in  charcoal sludge similar to the problems of using sawdust?
 
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