Human BIOGAS Waste as Fertilizer

Please refer to this web article: https://investigatemidwest.org/2024/08/07/fertilizer-from-human-waste-faces-scrutiny-but-remains-a-profitable-industry/

I've been a Project Manager at a Wastewater Treatment Plant for 10 years, I have seen all of the processes required to deliver clean effluent to a river taken from human waste. I still would not drink it. The biological bacteria for creating biogas are anaerobic. These bacteria are now in you gut maybe 10 species or more according to the poster I saw and the chemist at the plant. They eat poop and create methane and CO2. One of the plant processes adds methanol to the mix, buy this time aerobic "bugs" are chowing down, they consider this ICE CREAM. This task is to remove Nitrogen which kills fish in the river. The methanol is a carbon source and the nitrogen is like a protein. When the bugs chow down on NO2 or NO3 they steal the nitrogen molecule and release the oxygen or the O2 or 03 from the waste water. Now the process removes a lot of junk like credit card scrap, bottle scrap and even bones, but it cannot remove forever chemicals. Except when Synagro a multi-national company, took the sludge from the separation of solids from liquids and turned it into charcoal. They sell this to farmers who spread activated charcoal on vegetable fields. My recommendation is to do the same thing, use the heat from sustainable methane to turn the solids into carbon and to evaporate the water from the micro solids in the effluent and collect the condensate. The current process dumps the drawn effluent from the sludge and returns to the liquid process. We need a smaller system that completes this task without energy inputs from the grid so that our toilet system can do the same along with the animal and vegetable wastes that can be processed into biogas, fertilizer and clean water.

It seems like the worst elements of this mess come from not controlling what goes into the sewage system and using it as a trash can.

If you're offgrid you can control what goes into your sewage system, so you don't need to worry about chemical contaminants.

Why not use an indian deenbandhu small scale biogas plant and make biochar out of the slurry output if you can't compost it for long enough to neutralize any health concerns before returning it to the soil?



Ideally I would either make compost out of the output, or burn it as the heat source in a Stirling Engine Combined Heat and Power generator.  I have made other posts about the stirling and the biogas and compost both would be good fuel sources for it...

...and thats if you don't want to just compost, right?

The bigger issue, to me, is that biogas is like 25x more potent as a greenhouse gas than carbon dioxide, and a bunch of home biogas plants are sure to leak it in ways that are impossible to regulate. So aerobic decomposition seems like it has a significant edge in being better for the environment from a realistic perspective.