Water filters purify water by using various methods to remove unwanted contaminants. The specific method depends on the type of filter.
Filtration Mechanisms
Most home water filters employ one or more of the following mechanisms:
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Sediment Filtration: A physical process where a porous material, like a nonwoven element, traps larger particles such as sediment and rust. As water passes through, these larger impurities are blocked, leaving cleaner water. (Brita® faucet filters, for example, use this method to reduce sediment.)
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Activated Carbon Adsorption: This utilizes activated carbon (charcoal) to attract and trap smaller contaminants like chlorine, benzene, and some organic chemicals. The carbon's porous structure provides a large surface area for adsorption to occur. (Many filters, including Brita, utilize carbon blocks for this purpose.)
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Reverse Osmosis (RO): An advanced filtration technique that uses pressure to force water through a semi-permeable membrane. This membrane effectively removes dissolved solids, bacteria, and other contaminants. (This is noted as the only effective method for removing harmful bacteria in some sources.)
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Other Methods: Some filters might use a combination of materials, such as a blend of filter media, to remove a broader range of contaminants.
Contaminants Removed
The specific contaminants removed vary widely depending on the filter's design and the filter media used. Some filters target specific pollutants like lead and chlorine, while others offer broader contaminant reduction. Many filters improve taste and odor as well. (Brita filters are cited as reducing lead, chlorine, asbestos, benzene, and particulates, while other sources mention the removal of bacteria, fungi, parasites, copper, and other pollutants.)
It's crucial to check the manufacturer's specifications to understand what a specific filter removes or reduces. Remember that no filter can remove all contaminants.
Filter Types and Applications
Various filter types cater to different needs:
- Pitcher Filters: Convenient and affordable, ideal for smaller households.
- Faucet Filters: Attach directly to the faucet, providing filtered water on demand.
- Countertop Filters: Offer higher filtration capacity compared to pitcher filters.
- Whole-House Filters: Installed on the main water line, filtering water for the entire house.
- Under-Sink Filters: Compact and discreet, offering various filtration levels.
Choosing the right filter depends on factors such as budget, household size, and the specific contaminants you want to remove. Consider your water quality report and personal preferences when making a decision.
