Producing drinking water is one of the most important applications of reverse osmosis. While it was originally used for desalinating seawater, the decontaminating capabilities of reverse osmosis makes it effective for producing mineral-free drinking water. Drinking water treatment has two goals, both improving taste and ensuring safety.
The types of treatment vary depending on the size of the system, whether the source is ground water or surface water, and the quality of the source water
Many groundwater systems can satisfy all federal requirements without any treatment, but others need disinfection or mineral reduction..
Most surface water used for the production of drinking water requires filtration to remove turbidity and suspended solids before it can be used safely.
A variety of methods are used to treat drinking water, often in combinations.
- Filtration: Many water treatment facilities use filtration to remove all particles from the water. Those particles include clays and silts, natural organic matter, precipitates from other treatment processes in the facility, iron and manganese, and microorganisms. Filtration clarifies water and enhances the effectiveness of disinfection. The type of filtration used can include micrifiltration, ultrafiltration, microfiltration or reverse osmosis.
- Ion Exchange: Ion exchange processes are used to remove inorganic contaminants if they cannot be removed adequately by filtration or sedimentation. Ion exchange can be used to treat hard water. It can also be used to remove arsenic, chromium, excess fluoride, nitrates, radium, and uranium.
- Absorption: Organic contaminants, unwanted coloring, and taste- or odor-causing compounds can stick to the surface of granular or powder activated carbon and are thus removed from the drinking water.
- Disinfection: Water is often disinfected before it enters the distribution system to ensure that potentially dangerous microbe and microbial organisms (including bacteria). Testing for these contaminants takes place on varying schedules and at different locations throughout the water system. UV treatment and ozonation are safe, nonchemical methods of disinfection.