101–110 of 120 posts
Seems like these systems assume only human urine will go into these storage systems. But in reality, people tend to flush more than just fecal matter, urine, and water down the drain. In order to clean the toilet bowl, people will use highly poisonous cleaning solutions. How will these cleaning solutions mixed with the stored urine affect its usage as a fertilizer? Even if it is eventually dehydrated, wouldn’t some o…
Seems like these systems assume only human urine will go into these storage systems. But in reality, people tend to flush more than just fecal matter, urine, and water down the drain. In order to clean the toilet bowl, people will use highly poisonous cleaning solutions. How will these cleaning solutions mixed with the stored urine affect its usage as a fertilizer? Even if it is eventually dehydrated, wouldn’t some o…
An interesting implication of that is that bacteria will break down parts of the urine into ammonia, and a little bit for feces but not as much.
If someone were to dump bleach into it, it might create chloramine gas. Emphasis on might there; I'm in no way qualified to evaluate that risk.
Separating urine from the rest of sewage could mitigate some difficult environmental problems, but there are big obstacles to radically re-engineering one of the most basic aspects of life. I briefly had a project called Pee on a Tree that got mocked and got no traction. This is why Earth is doomed: The simple solutions are derided while people overcomplicate things that don't have to be complicated. Hoomans: Y'all f…
I remember when Obama was roundly mocked for suggesting that people improve gas mileage by checking their tire pressure before road trips. Too easy and effective to be worthwhile, I guess.
Seems like these systems assume only human urine will go into these storage systems. But in reality, people tend to flush more than just fecal matter, urine, and water down the drain. In order to clean the toilet bowl, people will use highly poisonous cleaning solutions. How will these cleaning solutions mixed with the stored urine affect its usage as a fertilizer? Even if it is eventually dehydrated, wouldn’t some o…
Earlier quoted context omitted.
The composting process destroys pathogens by several mechanisms. The first is heat: in the pile, thermophilic bacteria raise the temperature through their own biological heat, killing E. coli, Salmonella, etc. My current pile was 149F (65C) yesterday. In a compost pile, those temps will kill pathogens in less than an hour. As a general rule of thumb the following temps/times kill pathogens in compost piles: 140F/60C…
I would also worry a bit about accumulation of drugs like lithium and other contaminants like PFCs. My suspicion is long term closed loop use of toilet compost for food crops could result in unsafe levels of contamination, have you done any research that direction?
PFCs may accumulate almost regardless, although I assume composting helps. After all, composting can break down gasoline, diesel, and TNT - though of course you shouldn't add them to a compost bin! Quoting The Humanure Handbook (4th edition) page 115: "About half the sewage sludge (biosolids) produced in the USA is applied to land, providing a significant opportunity for contaminants to enter soil systems and to bioaccumulate over time..." And page 117: "For example, brominated fire retardants were still found at almost eight thousand times higher concentrations than background concentrations in soil samples twenty years after the last application of biosolids. In another study, fifteen out of nineteen pharmaceutical drugs were still present in soil six months after being irrigated with contaminated wastewater."
So PFC accumulation is already happening but not because of composting. It's happening because sewage sludge is being added to farm fields and new housing developments.
This is part of why I cook with clay (in solar cooking) and stainless steel on the stovetop. That way my nutrient loop (eat, excrete, compost, grow more food) has the absolute minimum of PFCs and other contaminants.
For more information, read chapter 10 of The Humanure Handbook (4th edition) by Joseph Jenkins.
Why not keep the pee and poop mixed, and use it to harvest biomethane? Effluent can still be used as fertilizer after capturing the gas. https://www.sciencedirect.com/science/article/pii/S097308261...
> Using an inoculum acclimated to high ammonia concentrations was critical to successful biogas production at these high TAN concentrations.
That's what this part is talking about. They intentionally introduced bacteria that were tolerant of high ammonia levels to work around all the ammonia the urine gives off. The wild-type bacteria aren't tolerant of those levels of ammonia, and do a poor job of digesting the feces when mixed.
Why not keep the pee and poop mixed, and use it to harvest biomethane? Effluent can still be used as fertilizer after capturing the gas. https://www.sciencedirect.com/science/article/pii/S097308261...
Vice did a good documentary on NYC's effort to do just this You Don't Know Shit https://www.youtube.com/watch?v=ZiNiBZiR_uA https://www.youtube.com/watch?v=EVGdmE4_h4c https://www.youtube.com/watch?v=Ra47l7fihZU
Earlier quoted context omitted.
I would also worry a bit about accumulation of drugs like lithium and other contaminants like PFCs. My suspicion is long term closed loop use of toilet compost for food crops could result in unsafe levels of contamination, have you done any research that direction?
I don't know about lithium in compost, but in general, composting breaks down many pharmaceuticals (again, apart from certain chemo drugs). Composting does destroy some anti-cancer drugs like Salinomycin. PFCs may accumulate almost regardless, although I assume composting helps. After all, composting can break down gasoline, diesel, and TNT - though of course you shouldn't add them to a compost bin! Quoting The Human…
https://www.mainepublic.org/environment-and-outdoors/2022-02...
In my area the majority of contamination is from firefighting foams, and I think in the Bay area there's also a lot in groundwater from semiconductor manufacturing. My understanding is the known way to remove PFCs from soil involves baking at very high temperatures (like 500C) which is impractical at any scale.