Eli5: what exactly does it mean when sewage is treated them released into a river?

Question

So the city it talking about treating sewage before dumping it into a river that I see tons of people swimming and fishing in. How does this work?

In: 11

Answer 1

Usually a bacteria is used in a big vat that eats the poo. This leaves the water.
Other chemicals may be used that clean the poo water by killing bacteria and viruses that are left. This is then put back in the river