Biological & Viral Water Purification

Biologically contaminated water contains harmful microbes like parasites, bacteria and viruses. To avoid playing host to these microscopic vagabonds, it's essential to ensure your drinking water is purified, especially when the quality of the source is unknown.

Types

• High doses of ultraviolet light irradiate and destroy viruses and bacteria, although other marauders like Giardia parasites may survive the slaughter. Treatment with chlorine chemicals, ozone or iodine can kill many pathogens; boiling the water is also extremely effective. Some filtration systems like reverse osmosis can remove viruses and other biological contaminants, although other filters with larger pore sizes may permit viruses to pass through.

Effects

• The efficacy of chemical treatment depends on the chemical, its concentration and external factors like the pH of the solution. Water treated with ozone must usually be chlorinated as well, since ozone breaks down quickly and doesn't persist for very long in the water. Boiling water is the most foolproof method of emergency water purification but is seldom practical for home filtration systems because of the amount of energy it consumes.

Considerations

• Microfiltration and ultrafiltration do not remove viruses. Reverse osmosis and nanofiltration, however, trap viruses and other biological contaminants. Distillation and ultraviolet treatment can both destroy biological contaminants but are expensive and must be properly maintained to be effective.