Hello all, I'm sure the topic of bokashi-adjacent toilet systems has come up here, here's my addition to the bucket. I'm happy to define or elaborate on any jargon I'm using here (or just google it). This is a compilation of my notes and includes an ask for help at the end.
I've been working on a project incorporating some of the more obscure academic work on the topic, primarily from the world of ecosan and terra preta research, plus knowledge from KNF, bokashi, and permaculture wingnut youtube into a cheap, layperson-friendly system that can be used on a household basis in emergency and/or poverty scenarios. Or just for fun.
An ideal human waste sanitation system achieves these goals:
-odor removal
-sanitation through acidification, killing coliform, preventing water contamination
-soil production
-scalability
-quick processing time
My goals that surpass what I know to exist so far, in combination, are a human waste sanitation system with:
-100% cheap and widely available inputs and equipment
-simple instructions
-results that can be verified by sensory cues, rather than lab testing
-(preferably) a system not requiring urine separation, though it may be desirable for weight reasons
Existing Systems
The modern Terra Preta system (
https://www.tuhh.de/aww/en/research/terra-preta-sanitation ) requires 3 steps: Biochar production and addition to human waste, lactic acid fermentation (LAF), and vermicomposting. Vermicomposting and biochar production are complicated and, based on my reading, unnecessary for odor removal and sanitation. Of course, the biochar and worm composting add to the soil-building process, but are far less accessible processes than LAF.
Bokashi is a fermentation-based composting system in which laboratory grown Effective Microorganisms (EM), a combination of specific LAB, yeasts, and other bacteria, are propagated on wheat bran, fed a little molasses, making bokashi bran. The bokashi bran is then layered with food waste, left in a closed bucket for a few weeks, during which time it acidifies to pH 3 or 4. This "pre-compost" is too acidic to be used directly as soil, and is buried in the dirt to mysteriously de-acidify.
As far as I can tell, it's an overengineered/proprietary version of preexisting east asian composting systems reminiscent of a nuka pot.
The advantage of Bokashi over aerobic and anaerobic composting is that it doesn't offgas, doesn't lose any nitrogen, doesn't require much space except the burial site, and doesn't require large inputs of "browns."
There's a proprietary bokashi/EM system for "pet waste" available (
https://store.bokashicycle.com/bpcfs ) that at least one person has documented using for some years for human waste sanitation/soil production (
https://tinyreddesk.blogspot.com/2017/08/the-toilet-report-and-bokashi-upgrade.html ) (
https://tinyreddesk.blogspot.com/2023/01/the-dtao-of-poop-update.html ). The system is similar to regular EM-Bokashi, except that it involves combining the bokashi flakes and molasses in a bucket half-full of water, dumping in accumulated "pet waste," and sealing it off. That is, instead of gradually layering food waste and bokashi bran.
This paper (
https://www.tuhh.de/t3resources/aww/publikationen/pdf/TPS-IC/20_A_Yemaneh_et_al.pdf) concludes that a combination of LAB starter, and either 50% poop/50% kitchen waste, or 90% poop/10% molasses, will successfully ferment and achieve low enough pH to kill coliform.
These papers are also relevant. They successfully test a system mixing 50% poop with 50% "fermented rice flour," though the fermentation process isn't explained. They bring up that that starch-based (or at least cassava) substrate attracts heterofermentive LAB (which produce CO2, bad) rather than homofermentive LAB (don't produce CO2, just lactic acid, good).
https://www.researchgate.net/publication/323404528_Locally_Produced_Lactic_Acid_Bacteria_for_Pathogen_Inactivation_and_Odor_Control_in_Fecal_Sludge
https://www.researchgate.net/publication/324277850_Optimization_of_lactic_acid_fermentation_for_pathogen_inactivation_in_fecal_sludge
Anaerobic poop composting (in closed containers) produces methane which is sometimes intentionally done to capture methane for fuel.
The "classic" humanure system (
https://humanurehandbook.com/humanure_basics.html ) is widely used, and has a lot of problems:
-loss of significant of nutrients via offgassing, ie....
-greenhouse gas emissions
-requires lots of space and inputs
-year+ processing time
Alternative, cheap inputs
KNF-style lactic acid bacteria (LAB) preparations, and I believe Indigenous microorganism (IMO) preparations have been used successfully as a substitute for EM in bokashi-style composting. LAB and IMO are possible to prepare with cheap materials, excepting the milk the LAB preparation. This achieves the goal of cheap/available inputs. In KNF, LAB are cultivated by letting rice wash water sit out for a few days and go sour, then adding 1 part of this "serum" to 10 parts of milk, letting it separate, and extracting the liquid whey layer which is theoretically full of LAB.
"People on the internet" bokashi composting using homegrown LAB: (
https://www.youtube.com/watch?v=3rvFLSLdWv0 )
(
https://old.reddit.com/r/knf/comments/1ajabjf/bokashi_vs_imo3/ ), and I believe KNF IMO. I'm sure there is a ton of information in Korean on adjacent or older systems.
I've made what smells and appears to be a LAB preparation from an alternative medium described here (
https://www.mdpi.com/2311-5637/9/3/216) made of water, and small amounts of soy flour and sweet potato. The sweet potato/soy broth separates and drops from pH 6 to pH of 4 in 24 hours, as opposed to milk which takes far longer. This ticks the box of "media cheaper than milk." Though whey is plentiful in some agricultural areas, it isn't everywhere.
WTF am I doing
Pooping in a bucket, in various creative ways mixing existing, non-academic systems with my (limited) understanding of the academic research. Testing the impact of filtered vs tap water (chloramine) on starters, attempting to deactivate the chloramine. Testing different media for LAB cultivation.
As you can see, there are people using EM-bokashi to process human waste, there are people using homemade LAB to replace EM in the bokashi system, but no one is
cultivating LAB for bokashi for processing human waste. Or, they are, but exclusively in the academic/international development world, and have not disseminated accessible information on the process.
While all of the above sounds great in academic papers, I couldn't rightly write up a pamphlet or give a workshop on the topic without proven, repeatable results in a non-lab setting. Despite all the promising research, I have not yet achieved fully acceptable results. But, I've only started doing trials recently after a few years of research. I may try to do some "testing" at a yearly hippie fest in these parts, I'm sure they'll be amenable and I have an "in" with the poop crew.
Why I need a trained microbiologist friend who's willing to help with this, hopefully living in Portland, Oregon (a guy can dream):
-I have random questions about the process come up, it'd be great to have someone to PM about it. I've taken nursing microbiology, but am often at a loss regarding baseline information
-Help decoding academic research
-While i'm intentionally doing this in a non-laboratory
setting, I still need laboratory
testing and verification of results to see if everything is going well, namely to correlate visual/smell cues to microbial changes. Would be great to have guidance on how/where to get testing done, or even better, someone with lab access...
Hope this all made sense, thanks for reading! Please tag or send over people you think would be interested and helpful.
miscellany:
https://www.researchgate.net/publication/328227531_Application_of_lactic_acid_derived_from_food_waste_on_pathogen_inactivation_in_fecal_sludge_A_review_on_the_alternative_use_of_food_waste
