Humans would be unable to live without the bacteria that inhabit the intestines and assist in digesting food. Only a small percentage of bacteria cause disease in normal, healthy humans. Other bacteria can cause infections if they get into a cut or wound. Chlorine is a chemical used to disinfect water. Chlorine is extremely reactive, and when it comes in contact with microorganisms in water it kills them.
Chlorine is added to swimming pools to keep the water safe for swimming.
Chlorine is available as solid tablets for swimming pools. Glendale's drinking water treatment plants use chlorine in a gas form because of the large volumes required. Chlorine is very effective against algae , bacteria and viruses . Protozoa are resistant to chlorine because they have thick coats. Protozoa are removed from drinking water by filtration .