Radiant zones and communities building..where are we up to ?

[Vidya Moksha]

Originally Posted by TtC

It depends what is meant by "toxic." It is a matter of perspective. It would most likely be toxic to humans and most mammals as well as fish, but not to worms, bacteria, some insects, and the like.

Of course. I wasnt sure of the depth of inquiry in the first question...its toxic in the sense that it contains gut bacteria (eg E.coli) which are directly harmful to humans and other vertebrates if ingested. The usual source of ingestion is polluted water supply. It is also possible for some nasty viruses to be present.
In another sense it is 'toxic' because it has a high BOD and COD (Biological and Chemical Oxygen Demand) which means bacteria and certain chemicals 'digest' (or oxidize) the faecal matter, and in so doing the use up all available oxygen, which is why most aquatic organisms suffer, many are extremely sensitive to reduced oxygen levels.
On the other hand, many animals thrive in such conditions, they see the sewage as food and they dont mind the reduced oxygen so much.
The 'toxic' elements are contained within the sewage water, so when this contaminated water seeps, or leaks from the digester it spreads to the surrounding area. This is no real problem unless local groundwater is contaminated in the process.
Mixing sewage with water is always potentially hazardous, and always wasteful of water. Dry toilets are the better solution, i believe.