What is the concentration(mg/L) of Chlorine Disinfectant to kill the unwanted micro-organism in water?

3-5 ppm should be maintain to kill micro organism, it also depends upon the water suspended solids level.  if ss more it will consume more chlorine due chlorine break-point.  so do some jar test and then fix it.

But final water before discharge should be less than0.5 ppm.

-1-2 ppm is adequate for baterial disinfection

- Residual chlorine is to be not more than0.1-0.2 ppm

from 0.1: 0.1.5 mg / l