Disinfection systems are used to combat waterborne diseases caused by bacteria or viruses. These processes neutralize pathogens by treating source water with chemical additives, or through exposure to ultraviolet light. These treatment systems are often inexpensive and can easily be scaled down for low-volume treatment facilities.
Free chlorine, chloramines, and chlorine dioxide are common disinfectants. Chlorination is the most popular (and oldest) class of chemical additives. Chlorine is also an oxidizer, so it helps to remove iron, hydrogen sulfide, and other minerals.
Ozone, a colorless gas, treats organic and inorganic contaminants in much the same way as chlorination but is even more effective against bacteria and other germs. Ozone systems are uncommon in much of the world because they are infrastructure intensive, and they can be expensive to implement.
Ultraviolet light, an invisible part of the electromagnetic spectrum that kills bacteria and viruses in water exposed to its rays, is typically produced using mercury lamps. The UV process is affordable and popular with small-scale facilities but is not as effective as other disinfectants on surface water supplies containing lots of suspended particles.