Festival scale humanure composting

Beau Davidson wrote:Lots of different ideas around Permies.  

Have you read up on willow feeders?  
https://permies.com/t/161838/willow-feeder#1274768

You could be first to get this certification:
https://permies.com/wiki/156829/pep-greywater-willow-feeders/Willow-Feeder-Fair-Event-Public

I'm sure others will have input as well.

I'm really glad you're going this route.  Pleast share your progress and outcome!  The world needs more good examples of scaleable, ecologically sensible waste management.

Kenneth Elwell wrote:Ironic that your buckets are sitting in a building designed for managing cow poop and urine...

A biodigester could be another option
solarcities has information about building one.

Doug Sass wrote:Hi Xavier
I read read your post.   What a load of cr^p!   About 1,000-1,500 gallons by my estimation.    I wanted to offer some thinking to an already suggested idea.   First my credentials:  as a boy growing up on a farm I became interested in biogas production after reading Mother Earth News Handbook of Homemade Power.   I built a digester and operated it to the amazement of visitors until one day I blew myself up.   Such is the life of a young inquisitive pioneer.   I have also been involved in fecal production for many years.   It seems your current approach has some issues:
1) Handling.    The waste requires much handling due to the 20l containers.    I would like to meet the brave folks who volunteered for this task.    Perhaps not shake their hands but at least have a beer with them and get to know true heroes.  
2) System Complexity.      Separating the waste streams caused problems.    What to do with all those buckets?    If it were my town, just put each one in an Amazon box on the porch.    It would be gone the next day!
3) Time.    The aerobic process takes 1,2 years.   Time for another festival, time for more buckets!
4) Cost.    Lots of buckets and lids and a place to store them long term.

Although I am not aware of an example of this being done,  perhaps this might better be accomplished with anaerobic bio digestion.  
1). Handling.   I suggest going straight into 55gallon drums (pardon my English units).    Would reduce the handling by ~90%.   Some styles have a completely open top and can be sealed with a clampy device lid prior to moving.
2) Complexity.    Biogas production works best with the right ratio of nitrogen and carbon.    Both streams go together.    Perhaps the barrel is pre-seeded with the right amount of used coffee grounds or some other convenient carbon source or perhaps it could be introduced after each use.  
3) Time.    Anaerobic digestion occurs much more quickly under the proper conditions.    Probably complete within two months.  
4) Cost.  Probably 1 55g drum costs less than 10 20l buckets

What would this look like?   All the drums would need to be placed in a building where temperature could be somewhat controlled.  If the temperature drops, no problem, process just slows down.    All the drums are tied together with a gas line coming off the top.     It goes to another set of drums, one upside down in water to prevent mixing of air and methane.   Methane is a more powerful greenhouse gas than carbon dioxide so it is immediately burned off and used to heat the building to maintain optimal temperature.  I would expect with the aerobic systems you have described that methane is still being produced and released.     When the gas stops bubbling, anaerobic digestion is complete and all pathogens have been neutralized.   Next step would be to spread the effluent on a farmland.    Would be an excellent project to work in collaboration with a university so every aspect could be measured and documented.  

I've used composting toilet for multi-day camps of up to 50 in the woods. Probably about 250 person-poop-days, total. Based on the Humanure Handbook system of sawdust, buckets, and keeping urine and poop together. People inexperienced with sawdust definitely do make a mess, and are hesitant about using it at first. From a user perspective, it it is important that each user does a "flush" with a scoop of sawdust to leave it clean and welcoming for the next person. Loose sawdust spills on the floor and looks messy.

For something like a festival I would go for a floor with wooden slats so loose sawdust drops through and doesn't build up.

If using buckets you need someone dedicated to swapping them out and keeping the area clean.

When you are done you don't really want things composting anaerobically in sealed buckets. Ideally you want a really hot aerobic compost heap. This is very situation dependent, but you could haul buckets off site and have a heap elsewhere. For the scale you are looking at I would probably construct a long "wall of haybales, so you can empty buckets over the wall without risking any splashback etc...

Getting it out of containers as soon as possible and into a compost heap does seem to make the whole process less stinky and unpleasant. And if being used correctly, with plenty of sawdust, no stage of the process should be stinky anyway. Nasty stink only happens with insufficient sawdust, not using it to cover between each user, or if it get sealed airtight and has time to go anaerobic. Sawdust is amazing at absorbing odour, and getting a really hot and sterile heap up to temperature fast.

Hi Xavier
I could not find a definitive article on Mitigation of pathogens through anaerobic digestion just many articles suggesting this is the case.    The ideal temperature for digestion occurs about 90-95 F.    Digestion also occurs at temperatures  120-150ish with a different type of microbes and this range i understand is more effective in reducing pathogens.    You need about a 30/1 carbon to Nitrogen ratio for optimum results so sawdust would be beneficial.     Also i did not mention that this process works better as a slurry (probably about 1/1) so more handling is required to add water.     I agree with Michael that your bucket system and even more so your tote system will quickly go anaerobic unless transferred to some other containment.    The batch system i described above is very similar to what I built years ago except I used a tractor tire inner tube to capture the gas.  
I think the promise of fast aerobic decomposition is rarely realized due to not being able to achieve aerobic conditions throughout.    Compost piles must be turned.  
Another issue I see with this festival waste stream even after successful remediation, it will contain trash and cups and more than a few cell phones so where do you put it to not pollute the environment?    You may still be faced with having it processed through a municipality.
I would like to know more about the system used at the festival Michael mentioned.    
This is great problem begging for a great solution.  

Hi Xavier:

I'm Jeinny and we manufacture WCEco compost toilets, we rent them for masive events, we have a collection service in 5 major cities in Mexico, and process everything.
The largest event we have handle was an Ecobazar with ~6000 visitors during 2 days, but it's not the onlu one. Before that we serviced a Bycicle race with 2400 participants. And we are just getting ready for an event of 45,000 next month.

We never use diverting systems in public events, as they always lead to problems because people do not know what to do with the sawdust and tend to screw it. We use 20L buckets and have personnel there to change them and to be sure everything is going right. It's important and conveniento to use enough sawdust. Not only helps to have a 30:1 carbon:nitrogen ratio, but also, not diverting adds adequate humidity to the compost process.

After the event we process everything in composters 2x2 m composters. But recently we worked with a major university here in México to test the pathogen charge of the final product after a year in the composter and after processing it as bokashi and found that not all pathogens are gone, so know we are being extra cautious and we are working in making some changes to the compost process. So, I'm pretty sure the volume in a bucket is not enough to reach adequate temperatures to kill pathgens. I would recomend to process externally in composters larger dthan 1 m3.

You can see some images of our cabins for events here:
https://www.facebook.com/media/set/?set=a.1571973673228019

And some images of our composters here
https://www.facebook.com/media/set/?set=a.1571991936559526

xavier be wrote:was it both your compost piles and a separate bokashi method (in buckets?) that were not successful in removing pathogens?

We do not process them in buckets. They stay in buckets just until we send them to the process area (about 3 weeks after collecting them).  We have serveral composters (2x3m and 2x2m). We have some of the composters' results out off the norm, specially helmints eggs, and also in the bokashi but in lower qtty. Those were preliminar results and we will be analysing them with the investigators and will be conducting some more test and preparing processing variants to fully understand whats going on.

Did you monitor the temps in the compost?

Yes, we monitor temp an pH 3 times a day on each composter. Mexican norms requires that temp is above 55°C for 72 hours. We acomplish that but we will do it everything again making sure all process is correctly handled and all the measurements are correctly taken.

I guess your climate is quite warm there?

We have a 14°C average with min. 3°C and maximun on 24°C

I have to add that we worked our composters according to Jenking's method and one of our guesses on this results is that maybe there is not enough aereation, but we will test that too.

For the quality of nutrients and level of humification, the results were ok.

Burton Sparks wrote:Xavier, I think the IBC tote is an interesting idea.  I've managed composting toilets for a 3-day event with over 75 people.  We opted to use 55 gallon drums using the Omick Barrel Design but without urine diversion to reduce maintenance all around.  We received lots of positive comments and no negatives.  The barrels were hard to move though.  In my experience people prefer the depth of a 55gallon drum over the 5gallon bucket.  IBC totes would allow you to move them with a tractor, provide a comfortable space between user and the growing pile, and control leachate.

In the Jenkins method (which I currently use) the deep cover layer on the bottom and sides, along with digging a depression in the middle for fresh deposits helps keep the pile sufficiently aerobic.  Early on I wasn't doing a good job digging the center depression and noticed actinobacteria building up, indicating it was starting to go anaerobic in the middle, but it never went fully anaerobic.  On the flip side, I've learned to put cardboard around the sides of the piles because I've seen winter winds kill a pile in a matter of hours without it.  Based on my experience I'd worry that an IBC tote would not give you the air you want to stay aerobic, but having said that, high enough temperature over time will still kill pathogens even if it goes anaerobic and stinks.

If the pallet doesn't crack the raised edges of the base ridges and sides of an IBC tote under load, you could consider crossing the your proposed design with a Johnson-Su type passive aeration system (all compost is within a foot of an air tube).  You'd want to cap the air tubes during use/fill, and align them so they don't sit directly under the toilet seat.  You could also surround each IBC tote with something like a Tree Bog, with a front gate to allow removal by tractor.  In the storage location you could insulatie the outsides with strawbales.

For this method to effectively hot compost, you'd want to fill each bin rather fast (1, maybe 2 days) because it'll start to heat quickly.  You may also want to have a way of having the maintenance crew spread the contents within the bin being filled, perhaps using access hatches like ceiling tile boards for the "bathroom" floor.  As an alternative, if you have access to electricity you could consider setting up an active aeration system inside the IBC totes similar to the O2Compost Micro-Bin, which would allow you to fill the bin over the full week.

Just an observation.

You are concerned about leachate, which in understandable.

My experience has been that this is highly dependent on exactly what type of sawdust you are using. There is a vast difference in ability of different sawdusts to absorb liquid, and hence their tendency to go anaerobic and leach liquids. There are also differences in use that can affect this. For example, using "too much" sawdust is never a problem. At worst the compost is a bit slow to get going. But using too little sawdust can result in wet anaerobic sludge. Err on the side of going overboard with the sawdust and you should avoid leachate altogther.

Our best has been sweet chestnut sawdust from a local fencing yard. They can give us cubic meter bags for free. Their dust is very fine and dusty. A bucket of this after a few days of normal use is odourless, and the moisture from urine is evenly spread through the dust. There are no wet an sloppy portions to splash when you transfer to a heap.

Next has been our own dust from running the chainsaw. Tends to be bigger pieces.  A bit less absorbent, but adequate.

The worst was bought in pine shavings. We urgently needed an extra loo when the indoor toilet was not working for a week. Bought a few bags. It was basically waterproof. A wet sludge was at the bottom of each bucket. It was a pain to use, nasty to clean up, and slower to compost afterwards.

You could try Jeff Lawton's wheelie bin design.  I'm a little nervous about sending the leachate straight out though.  Maybe if you added worms so it could act a little more like a vermifilter.  Joe Jenkins suggests using wheelie bins might work great for municipal emergencies in his Compost Toilet Handbook, but more for the sake of transport.  You might find the book interesting as it covers many applications of his system around the world.

Morfydd St. Clair wrote:I have nothing to add regarding technical details, but suggest that perhaps you could reach out to Natural Event ( products webpage ) for ideas.  I know that before the pandemic they provided composting toilet services to at least two festivals I attended with good results.

xavier be wrote:We will get the digital thermometer results in a month or two.

Dilek Demiralp wrote: So I need the result urgently for the same situation which mentioned at first question.

xavier said, "Has anyone tried something like this? Would it generate enough heat to kill pathogens?

Jeinny Solis wrote:We have some of the composters' results out off the norm, specially helmints eggs, and also in the bokashi but in lower qtty. Those were preliminar results and we will be analysing them with the investigators and will be conducting some more test and preparing processing variants to fully understand whats going on...

I have to add that we worked our composters according to Jenking's method and one of our guesses on this results is that maybe there is not enough aereation, but we will test that too.