Wendy Howard

Susan Wakeman wrote:The system in Geneva was a new build. Water here is hard and can lead to lime scale build up when not flushed with enough water or left in the toilet. Bear in mind this is in an apartment block, so I suppose ease of use was a key factor.

Of course! I was thinking about ease of use and the article mentioned the difficulty small children have ... But the limescale would be a significant factor. Context is everything!

OK. That would make sense I guess. Though I'm asking myself why go to the considerable expense of ripping out ordinary flush toilets to install urine-diverting ones when all that's needed is just to have people not flush the toilet when they've only needed to urinate? Then the whole lot gets flushed when the person who wants to defecate uses it. Makes it easier for the kids too. On my own system, I have a tap instead of a fixed-volume flush mechanism. That way, you use only as much or as little water as necessary each time you use it.

Interesting! Have you experience of this system Susan beyond what you've posted here? I read the article and studied the diagram and I don't understand why the urine is being diverted. It appears to go into the vermicomposting bin just the same as the solids. (In my system, there's no separation because there's no need for it - the vermi-ecosystem treats the urine as effectively as it treats the solids.)

Sandy Wise wrote:Should we be concerned or is there anything else we can do to prevent standing water?  How deep have people successfully dug for the greenfilter? Any thoughts or suggestions in this area would be greatly appreciated.  If these concerns can be addressed a new project will be started in Peru within the next couple months.  

Hi Sandy

Sensible in your situation to divert greywater elsewhere. You have a lot of options as far as the green filter is concerned. It doesn't have to be a bed. You could also use a swale as a soakaway/greenfilter (if you have any sort of gradient at all) or pipe to mulch pits around trees and shrubs. The more you can spread the water, the better. You don't say how many of you will be using the toilet but using it for black water only is not a significant amount of water. You can also limit the number of flushes per day if you're really concerned.

Good luck! And if you go ahead with the project, please send me a case study for the website!! I'm hearing of people installing them, all over the place but still have yet to receive any documentation!

Rebecca Norman wrote:Good idea, thanks. I'll go back and throw some other compostable stuff in there along with the wood chunks.

Just make sure there's little or no fresh green material amongst it or the temperature will get too high for the worms!

Rebecca Norman wrote:By the way, don't use wood shavings! We asked our students to collect wood chips from around our construction site, but they filled the tank with wood shavings instead, so for the first week or two it smelled great and the water coming out was quite clear, but then the shavings clogged up so the water was backing up a bit in there, and it went anaerobic and started smelling bad in the whole area including the kitchen and dining hall. So I dug out all the wet stinky shavings and we filled it up with wood chunks from construction (no, nobody uses any pressure treated or chemical treated wood here, and minimal plywood was used in this project so the chips seem pretty clean). It's only been going another 2 weeks so I don't have anything meaningful to report yet.

I've found a proportion of coarse wood shavings are OK provided they're well mixed up with other material. Wood chunks are great but I'd also mix in some fast carbon sources like dead leaves, bracken ferns, straw, etc. The microbial part of the ecosystem uses carbon to neutralise any nitrates and it takes much longer to break down woody material.

Rob Lineberger wrote:Wow. Thank you, Wendy. I can completely picture what you're saying. Thankfully i can't smell it! You've convinced me. Im also much happier about this once i heard about using grey water or rain water to flush toilets. That makes good ecological sense to me. Is there any issue with using grey water in vermicomposting toilets?

No issue with grey water. You can retrofit these vermicomposting systems to septic systems. In these instances, you just need to ensure you have a well-mixed matrix of organic material that's coarse enough to allow the higher water throughput volume to drain off fast enough.

You could have a vermicomposting treatment system underneath a dry toilet, yes. You don't have to remove the top of the IBC either - you could just enlarge the central hole to fit the walls of your toilet. But bear in mind you need to keep moisture levels in the tank at around 60-75% and you would still need to drain off liquid (urine mostly) which, if it's the only liquid going into the tank, is possibly going to create some problems for the worms through build-up of inorganic salts. Having handwashing water going into the tank will help. As will the water used to clean the toilet (and drop toilets can get really horrid - it's amazing where solids can end up!).

While a properly functioning vermicomposting system doesn't smell bad at all, fresh deposits will provide a welcoming aroma for the next user for sure, especially if it's a straight drop into the tank. The worst nose offender with normal drop toilets though is urine. Many people who run them ask people to pee elsewhere for this reason. If you're not diluting urine with flush water, I can imagine this will also apply with a vermicomposting system.

The expense of a flush toilet is pretty insignificant if you source toilet bowls from the waste stream. You don't have to have a conventional cistern - mine uses a 50-litre wooden wine barrel with a tap so you use exactly the amount of water you need for each flush and there's no waiting around for the cistern to refill for the next person. Again, water containers can be sourced from the waste stream and a proper ball and brass float valve is much more reliable in my experience than these plastic units you find in modern cisterns. So that only leaves plastic piping, which is not exactly expensive. But the biggest advantage besides user-friendliness is the flush water ensures optimum hydration levels in the worm tank and dilutes the urine.

Zenais Buck wrote:We built a system in rural south west Oregon, based on Wendy's post. 2.5 years in and it is working perfectly. When it freezes, the worms just move to the interior of the bin and activity is slow. In early spring I toss in more worms, just to help handle any stuff that has collected over winter. Granted, we don't get 'deep' freezes.  So far we have only one hiccup; in the initial build I did not pay enough attention to screening the exit, and the thing got clogged, resulting in too much liquid retention that killed the worms.  I had to dig into it (it was not too awful) and create a guard around the exit that keeps the mulch out. Then we have a secondary screen right at the exit pipe (similar to Wendy's build). Anyway, once that was cleared it has been working like a charm ever since. It was installed  for my parents house on my off-grid property (my house still uses composting outhouse) and is used by 2 people. However, we had 13 people use it for a week and the system handled the fluxuation just fine. I ordered and installed low-flow Toto toilets for this system - they rock.

Wendy- thank you so much for sharing this work! It has been a blessing for my older parents to have an indoor toilet as they age.

Sweet! Thanks so much for letting me know! Could I ask you to PLEASE send me a write-up and some images for the case studies section on the website (email address on the website)? Be sure to document the initial problems as well! Everyone who installs this system promises me faithfully they will do this but I'm still waiting for the first one.

I want to start raising the profile of the system and am considering either a crowdfunder or applying for some environmental prize competition or another to raise funds to make a series of instructional videos and get professional translations for the website done (friends keep promising but the same thing happens as happens with the case studies ...). Having some good case studies on the site is going to make all the difference in being able to demonstrate uptake and effectiveness. And documenting all the various problems and their solutions is going to make for a much more robust system. That outlet is the weakest point. I've been designing a tank attachment which makes it much less prone to accidental blocking, but the problem at the moment is that the tap area profiles of IBC totes vary from manufacturer to manufacturer so making a universal fitting isn't so straightforward. Watch the website for developments though ...

Rebecca Norman wrote:Will the worms starve to death if we go away?
I don't have experience of this, but I think they'll survive for several months and then leave eggs if they do die, so I believe this system could recover after a few months of disuse.

You can take the guesswork out of this very simply. Many people installing my version of Anna Edey's system here in Portugal have holiday homes, so I recommend they simply add animal manures - horse, goat, etc - enough to keep the worms happy while they're away. I don't recommend cow manure as it's too liquid and a large quantity could tip the tank into anaerobic conditions.