Chlorine

[Isaacr]

How does chlorine kill bacteria in recycled water?

[incitatus]

It reacts with them. Essentially what happens is that the active chlorine in whatever form (normally hypochlorite) oxidises the bacterium, starting with the cell wall. Nothing will put up with this sort of treatment for long. The only things that will really survive this for any period of time are spore-forming organisms, and even they have trouble with it.