Chapter 10 Drinking Water Treatment

With particles removed, it only remains to provide disinfection so that no pathogens remain in the water. Protozoan pathogens are large in size and have been removed with other particles. Bacteria and viruses are now destroyed by addition of a disinfectant, chlorine (the same chemical present in bleach). Enough chlorine is added so that some remains to go out in the water distribution system, protecting the public once the water leaves the plant.

A viral pathogen... Rotavirus diarrhea	A bacterial pathogen... Salmonella typhi	A protozoan pathogen... Giardia lamblia