This process occurs when liquid, gas or dissolved or suspended matter adheres to the surface of, or in the pores of, an adsorbent media. Many filtration systems use carbon, charcoal or a blend of filter media to help reduce impurities. These systems generally reduce contaminants in one of two ways.
First, some contaminants are filtered mechanically, meaning they are large enough to be trapped in the pores of the filter. Other contaminants adhere to the surface of the filter media. Eventually, the surface area of the filter media becomes filled and no more contaminants can be adsorbed.
Or, in the case of mechanical filtration, the pores of the filter become so clogged with debris that water is unable to move through the filter effectively. While the latter is easy to spot, since the flow rate of the water being produced by the system slows dramatically, it's not as easy to tell when the surface area of the filter media has become full and needs to be changed.
These systems incorporate a cation exchange resin that is regenerated with sodium or potassium chloride. The softener reduces calcium and magnesium ions and replaces them with sodium or potassium ions.
These systems use ultraviolet light to disinfect water (Class A systems) or to reduce the amount of non-disease causing bacteria in water (Class B).
These systems incorporate a process that uses reverse pressure to force water through a semipermeable membrane. Most reverse osmosis systems incorporate one or more additional filters on either side of the membrane.
These systems heat water to the boiling point, and then collect the water vapor as it condenses, leaving behind contaminants such as heavy metals. Some contaminants that convert readily into gases, such as volatile organic chemicals, can carry over with the water vapor.
These products attach directly to the pipe just in front of the homeowner's shower head.