Humanure biochar

An idea popped into my head recently and I don't know if it has ever been done.
Could you use a urine diverting toilet to collect solid human waste into a removable chamber that doubles as a biochar burn chamber? This would change a potentially dangerous waste product into a valuable soil amendment.
Good idea or does it suck?

Making biochar out of humanure would drive off most of the nitrogen, which is one of the main plant nutrients present in the manure, and a limiting nutrient for gardening and vegetation in general. Conventional composting would lead to much less N loss.

I think you'd be wasting the special properties of poop by burning it. I'm trying to think more in the direction of maximum utilization of human leavings rather than a more disposal mentality. Yes, it would sterilize the poo, but you'd presumably lose some of the fertilizing and certainly some of the soil/microbe feeding properties. There are other way to make it safe, or just put it where it won't be contacted by people until broken down, like burying it. I'm going to try out a trench system using biochar as deposits are made, to basically make an engineered soil. The outhouse will move along the trench. I"m thinking this could make use of complimentary attributes. Biochar, holds nutrients and improves aeration and absorbs odor, poo adds nutrients, charges char, encourages active microbial activity by giving them stuff to eat. http://turkeysong.wordpress.com/2014/07/29/soil-banking-with-biochar-latrine/ Not for everyone, but it's simple and seems like it would make good use of poo, while being safe enough and, especially with the addition of some other stuff, creating a soil that might continue to be awesome for centuries. For permanent sites, I am partial to the Ecosan urine diverting designs. Though I've never used one, it seems like a good system, easy to maintain and saves probably the great majority of the nutrients. I'm definitely all about urine diversion. It's special property of being full of soluble nutrients can be use to great advantage for fertilizing where and when you want. I think it's important to be cognizant of the possible health hazards of human feces, I'm inclined to think burning it is probably unnecessary and probably somewhat wasteful of it's potential.

John, I think that's brilliant. If without urine, with sawdust, then baked in an oven/ gasifier, even ebola would be dead. The nitrogen's mostly in the pee, so charing the #2 and sawdust wouldn't lose much N. Maybe a clay pot would be a good, heat-tolerant container. Perhaps a metal barrel would fit over the clay pot for the charring. Or it could go on a shelf inside the woodstove.

I've thought about this too in the event that the municipal sewer didn't work or the septic got full and there was no hope of it being evacuated.

Assuming that your primary goal is sanitation and not worried about nutrient loss it would be a great idea..

That is how we processed human excrement on deployments in the Military with two exceptions:
1. We used JP-8 Diesel fuel to burn it down to ash.
2. Wouldn't dare use it for anything.

My only personal consideration would be turning it into bio-char.. and not burying it on my suburban lot due to drainage/sanitary concerns.
It's material that you would just be flushing down the toilet anyway. Pun intended..

If I had land I would definitely look into composting it for a wood lot / orchard soil amendment.

I know it's been touched on, but using humanure to make biochar seems kind of like you're overdoing things. If you're already making humanure, why not just use it? Unless of course you're looking to skip the wait period and turn it into something useful, and thus not a hygiene hazard, quicker.

Personally I'd just stick with wood biochar. I can also imagine charring excrement would bring about a quite unpleasant smell lol

Why not feed it to black soldier flies, who will turn it into sanitary, high quality chicken food.

I've thought about this as a village scale system, or an amendment to current waste systems where solids can be filtered out, dried and treated through pyrolysis. There have been experiments in Japan which have shown pyrolysis of such solid mixed waste can greatly reduce toxicity through the biochar's ability to absorb heavy metals and other toxic substances commonly put down the drain. Separating it at the source, however, is certainly a valid idea.

This would make sense to try with solar drying toilets installed in the early earth ships, adding on a urine diverting system.

From my experience making Biochar, I wouldn't want the process anywhere near any flammable structure. Have you considered being able to remove the container from the toilet before ignition?

Drying human feces will take a lot of space and be a hygiene problem because of flies, and a smell problem. Then someone will have to collect it and put it in containers to be put into ovens to make biochar. Even dried human feces are not pleasant -- believe me, I've seen a lot because I've lived in India for over 20 years!

It seems to me a lot more hygienic, and better for soil, to simply cover feces as soon as they are produced and let them compost. No smell, no flies, and good soil amendment produced at the end.

Rebecca

Yes, it is always easier to stick with what we know rather than experimenting with new things, but I don't think that was the question. Is it worth trying? I'd vote YES.

The fact is that in some situations, Biochar is more valuable than compost. In my climate, compost is gone within a matter of months, while Biochar may stick around for millennia.

As for the drying of faeces, I don't think anyone would suggest drying it in the open sun to be hygienic or worth the time.

If humanure was used in a large scale Biochar operation, the excess heat from the pyrolysis would be used to fully dry the separated solids of the next batch, as it is with any Biochar feedstock.

For a single toilet application, using a solar or otherwise heated toilet that dries the humanure in the vessel itself is a common concept and is effective at preventing flies and smells alike.

There is work being done on this subect referred to as terra preta sanitation -

P Lyons wrote:There is work being done on this subect referred to as terra preta sanitation -

As far as I can tell, the terra preta sanitation concept doesn't convert feces to charcoal, but uses charcoal from other sources to absorb nutrients from mixed urine and feces. So it differs from the original idea of this thread.

The lactic acid bacteria method of reducing smell that is mentioned in the terra preta sanitation videos interests me. I wonder if lactic acid bacteria can reduce odor from stored urine from a urine diversion toilet.

Brian - You assessment of my post is correct, I guess I misread the original posts.

There is a relatively recent post Storing Source Separated Urine which discusses various options associated with preventing odour from source separated urine, and some good information of using lactic acid bacteria.

I had the same questions about pharmaceuticals in the resulting compost, so I took out "The Humanure Handbook" by Jenkins. pp. 114-122 cover this.  However, the information feels a little bit all over the place.  And only a very few medications were covered.  And I'm curious about all of the new biologics that are delivered by tablet.  Those aren't broken down inside the body and so will be excreted in waste.

Because I'm interested in teaching permaculture and because I'm interested in village scale projects, I'd love a comprehensive list of medications and how long it takes for them to be broken down, how much remains after the composting process, or if it can't be broken down at all.

I really liked the terra preta video.  I love the ideas regarding mycoremediation.  Maybe it's overkill to consider doing all of those things together, but then perhaps it's worth it not to have as great a risk of toxins building up.  Both my own projects are quite near running water sources, so maybe my caution is heightened.

Nissa Gadbois wrote:I... I'm curious about all of the new biologics that are delivered by tablet.  Those aren't broken down inside the body and so will be excreted in waste.

Nissa Gadbois, I'm curious: is there a source that supports that new biologics aren't broken down in our bodies? I don't actually know a whole lot about these.

Brian
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Brian Cady wrote:
As far as I can tell, the terra preta sanitation concept doesn't convert feces to charcoal, but uses charcoal from other sources to absorb nutrients from mixed urine and feces. So it differs from the original idea of this thread.

Interesting. I've always thought that the addition of biochar to a composting toilet system would make a ton of sense. It'd charge the biochar and likely reduce odors significantly.

Brian Cady wrote:
Nissa Gadbois, I'm curious: is there a source that supports that new biologics aren't broken down in our bodies? I don't actually know a whole lot about these.

Brian
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I've taken biologics for an autoimmune disease for a couple of decades.  They used to be injectible only because they were broken down in the body.  They created ways for them not to be destroyed in the immune system so that now they can be taken orally. :)

Like the OP, I was wondering if anyone had made char out of humanure. But I did it myself first anyway  (just did so today, Dec. 24, 2024) and then
went looking to see if any one else had.  So I found what I was looking for and found it here to add my experience.

My compost toilet buckets stack up a while (6 or 7 months usually) before they get dumped into the humanure specific compost pile. I dont use it
for gardening so the pile is basically unused so far. (just my brother and I here going on 4 years) so the pile is still nowhere near being full. Smell
was an occasional problem only if it managed to get wet from rain. (leaky tarp I guess)

I saw a YT video where a guy used soup cans to make char in his woodstove over the winter heating season; so that is the method I am using for
pyrolization. For the compost toilet, fine flaked pine used for horse bedding gets sprinkled over the poo. No effort is made to divert urine. When
full, the lid is closed tight on top and gets put outside. I mostly try to keep it in the shade. Any time of the year. None have busted when frozen yet.  
And remarkably so far, the smell was not nearly as bad as I expected for bucket contents that had been sitting for several months. This might be
different for "fresher" bucket loads, but I haven't gotten to them yet.

The finished product is light and finely flaked and the occasinal clump of more compacted char crumbles very easily. No crushing is needed. It will
be great for sprinkling as is into the deep bedding in the chicken coops to absorb smell of amonia and chicken poo or to mix into garden soil (after
it gets innoculated with compost tea or with it already mixed in with the coop bedding that gets composted) or to put some in an open jar or dish
as a deoderizer to absorb odors in the kitchen and in the bathroom.

BTW, the fine pine flakes surprized me when I first started using the composting toilet. (5 gallon bucket with a toilet seat on top... quite simple but
adequate and effective )

Some smell was noted, but not nearly as noxious when at first when trying to use straw. (big, big mistake) So I used a spray bottle mixed with some
freerange, purebred unicorn fart juice that was certified !00% organic, non GMO, unsulphered, no PFAS or glyphosates, herbacide free, fungicide
free, insecticide free, petrochemical free, no antibiotics, non-allergenic and mixed with osmosis filtered well water. The poo pile would get covered
with a judicious coating of pine flakes and spritzed with a few squirts of the unicorn fart juice concoction. Now I never had smelled unicorn fart juice
before, but to me it smelled suspiciously like several drops of vanilla extract had been mixed in with the osmosis filtered well water. Apparently the
spray can also be had in peppermint or lavender versions and maybe others as well but I didn't try any of those. Anyway, I later discontinued use of
the spray since generally unicorns are as hard to come by as unobtainium and their fart juice even moreso.  That, and I just became accustomed to  
the slight vestigial waft of poo.  (and that could probably be cured with a dish of the humanure char nearby to absorb those odors.)