Water filters

Guest · Posted: Fri May 04, 2007 8:53 am Post subject: Water filters

My sister is considering getting a water filter. What is the best type of water filter for drinking water?

Allison Tannis · alive Expert Joined: 20 Apr 2007 Posts: 2

Filtering can remove contaminants found in Canadian tap water such as lead, aluminum, bacteria, parasites, pesticides, asbestos, fluoride, chlorine, sodium, and radon. There are several types of filtration systems available.

Activated carbon filters are the most commonly used water filters. They mechanically and ionically filter water to remove the unpleasant appearance, odour, and taste caused by some
bacteria, parasites, chlorine, and heavier metals and materials. They are not effective, however, at removing inorganic minerals such as fluoride. Carbon filters allow bacteria to breed in them, and hot water can cause contaminant release. Therefore, use only cold water in carbon filters and change them frequently.

Carbon filters are available in two forms: granulated carbon and solid carbon block. Solid carbon blocks clean more water and don’t have air pockets (like granulate carbon filters), thereby facilitating bacterial growth.

With reverse osmosis filters, water flows though special microporous membranes whose pores allow only the water molecule to pass through, while large inorganic and organic materials cannot. Some reverse osmosis units contain two or three filtering mechanisms: a sedimentation filter, which allows particulate to settle out of the water; a reverse osmosis membrane filter; and a carbon filter. A reverse osmosis filter with this three-tiered mechanism is thought to remove virtually all organic material and minerals.

Distillation and ultraviolet light (UV) filters are also gaining popularity. Distillation filters heat water to boil and then allow it to cool, removing all minerals and bacteria. However, this system is not energy efficient and does not remove all contaminants. UV filtration systems rely on UV light to kill bacteria in the water but do not remove contaminants such as lead. They should therefore be used in combination with an activated charcoal filter.