How much heat is generated by sewers?

Question

How much heat is generated by sewers?

Answer 1

Good question! A fair amount, but it is generally to low in temperature to be profitably harvested.

Compost generates enough heat that a large pile may set itself on fire.

It would seem sensible to operate a sewage plant, composting and a greenhouse together, capturing some of the additional heat and CO2 to help the plants grow, especially in temperate or polar climates, but I'm not sure if that's done.

Answer 2

I don't know but I am not using Ship to heat my house!