If it helps maybe you should direct your research to waste treatment plants. In Australia ive heard of one company processing the human waste to a level that is safer for human contact the processed material solids and liquids are put in large compost windrows and managed that way. Basically inoculating the compost with the waste and breaking it down to a soil form. All of the benefits but a more refined product that people don't think twice about buying.
Let us know what you find on the subject it is interesting and exciting to see good management of waste that can benefit the environment
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