Water is an abundant resource, but it is not always clean, clear, and ready to drink. Suspended particles, biological and other contaminants can alter the taste and odor of water or make it hazardous to your health. There are many different ways to purify water, some of which you can perform in your own home to ensure your water is safe.
Filtration
One of the most common techniques to purify water involves filtering it through a substance called activated charcoal. Activated charcoal consists of tiny charcoal particles with lots of nooks and crannies in their surface, producing a very high surface area. Many different types of contaminants are attracted to these particles and adhere to them, falling out of solution as the water passes through the filter.
Chlorination
While filtration will remove many types of particles suspended in water, it can have little to no effect on biological contaminants such as bacteria and viruses. According to the EPA, eight drops of chlorine bleach can render a gallon of water safe to drink. Municipal water systems add chlorine after filtering to prevent contamination as it flows through the system.
Reverse Osmosis
The natural mechanism of osmosis causes water to flow through a semi-permeable membrane according to density. Water naturally flows from an area of less dense particle concentration to one of higher concentration until the two sides are balanced. Reverse osmosis uses pressure to reverse this flow, trapping contaminants on one side of the barrier and allowing pure water to flow through to the other side.
Ultraviolet Purification
Many biological contaminants are susceptible to ultraviolet light. Simply exposing water to sunlight can eventually weaken and kill many types of bacteria. Using high-output UV lamps can speed up this process, destroying microorganisms and rendering the water sterile and safe to drink.
Ozone
Ozone is an unstable oxygen molecule that has the ability to oxidize anything it contacts. This process can destroy many different types of contaminants and kill bacteria, but ozone can also be harmful to humans in large quantities. Many treatment facilities that use ozone to purify water add an additional filtration step to remove any residual ozone before delivering water to customers.
Boiling
Bringing water to the boiling point is another way to render it safe to drink. According to the Environmental Protection Agency, boiling water for one full minute will kill any microorganisms that may be lurking in your water supply. Water authorities will usually issue orders to boil drinking water any time they detect or suspect large-scale contamination of the water supply.
References
- Centers For Disease Control and Prevention: Water Treatment
- U.S. Environmental Protection Agency: Emergency Disinfection of Drinking Water
- U.S. Environmental Protection Agency: Ground Water & Drinking Water Frequently Asked Questions
- U.S. Environmental Protection Agency: Treatment Technologies
- History of Water Filters: Water Treatment Alternatives - Reverse Osmosis
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