Once relegated to offices, water coolers are becoming increasingly popular as fixtures in the home. Water cooler filtration might have one filter or a combination of filter types, including reverse osmosis, activated carbon, ultraviolet, and ceramic filters. The type of filter needed depends on the quality of the tap water and the contaminants that affect the water’s taste, smell, and purity.
Some water coolers have bottles that must be changed when they are empty. The water in the bottles has usually been pre-treated and filtered. The purity of bottled water is often inconsistent, and it is possible for the plastic from the bottle to contaminate the water during storage. Other types of water coolers lack a bottle, with the filter built as part of the cooler. Some bottleless water coolers attach directly to the home or office plumbing system while others must be filled from the tap. Smaller tabletop and countertop models are available as well.
Reverse osmosis is a common type of water cooler filtration system that is used with larger water coolers connected to a plumbing system. In the reverse osmosis filtering process, the water is forced at high pressure through a porous membrane. The contaminants are trapped by the membrane and the clean water travels to a storage tank. Reverse osmosis can remove most organic and inorganic impurities, but it creates a large amount of wastewater.
Activated carbon is often used with a reverse osmosis water cooler filtration system to remove any synthetic chemicals that can pass through the reverse osmosis membrane. Activated carbon, also called activated charcoal, uses organic material that has been burned and then heat-treated to make it extremely porous. Through a process of adsorption, contaminants adhere to the carbon filter. Activated carbon filtering is also used on its own in smaller types of water cooler filtration systems because it can remove chlorine, pesticides, and organic chemical compounds.
Some water cooler filtration systems also use ultraviolet (UV) or ceramic filters to take out microbes like giardia and other parasites or waterborne cysts that make people ill. UV filters use mercury low pressure lights that kill microorganisms when the light hits them. Ceramic filters have micro-pores that are small enough to keep harmful microbes from passing through. Ceramic filters must be changed or cleaned regularly as contaminants build up on the outside and create a slime which renders the filter ineffective. UV and ceramic filters are insufficient on their own because they do not remove chemical contaminants.