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I assisted IMPILO YABANTU in developing a low-tech system (fully franchised will come out under $60k US) that can dry and carbonize faecal sludge, which over a period of 3 years (since 2017) morphed into 6 interconnected kilns (containing drum retorts) in a process we coined 'progressive batch' where gases flow from one kiln to the next in series. Some of it was funded by the Bill & Melinda Gates Foundation.
So my experience only relates to sterilizing faecal sludge, in which some lab samples contained up 400,000 coliform concentrations down to Nil. Our "biochar" product is sold to Regenerative Agriculture Specialisation (RA$) in South Africa. At this stage we see no use of placing coliforms back into the biochar we have spent considreable energy removing. They have already done extensive field trials with a product that contains biochar. Their product called VitaSoil has 4 components:
1. Biochar which provides the refuge for microbes
2. Decomposed pine sawdust - nutrient source
3. Vermicasts - diversity
4. Selected microbes with increased tolerance to chemicals and heat to help re-ignite soil biology
The natural "soil reef" created by above amendment will assist the natural microbes in the soil to flourish.
I would also point you to Green Peace efforts to counter the practice of dumping contaminated sewage on fields in the UK: https://youtu.be/jUdM3iK4O0c
The problem as I see it is that humans and animals that step onto these pathogens can spread it into households unintentionally.