Thursday, December 30, 2010

Water Filtration Systems for the Home

No single water treatment device treats all problems or is appropriate for all homes. Before you attempt a potentially ineffective remedy, the first and most important step is to have your water tested and fully analyzed by a laboratory. Only then will you have a true picture of the condition of your water and what if any treatment is necessary. A couple times a year some workman or other service provider who happens to be in my home or neighborhood tries to sell me a whole house filter system or water softening system. After examining my water analysis, I have no need for a filter system to remove solids. I have no treatment systems installed in my home so I do not need a filter to remove the residue from other treatments.

Filter systems are either activated carbon filters or mechanical filters. Carbon filters also called charcoal filters are water “polishers” they address minor odor and taste issues and are generally the finishing step when water is chlorinated to remove that swimming pool smell and taste. The ground up charcoal absorbs the contaminant and can be used for chlorine, residual pesticides and radon. Activated carbon filters cannot remove nitrate, bacteria or heavy metals. Nuisance bacteria do grow in the carbon medium thus it is important that these filters should be used in bacteria free water. This often results in multi step treatment systems. Filters need to be replaced regularly. These are four basic types of carbon filters (1) faucet mount; (2) in-line; (3) line bypass; and (4) point of entry (POE). Other types of carbon filters are pour through (portable) and specialty filters.

Faucet-mounted carbon filters attach to the kitchen faucet where drinking water comes out. In-line carbon filters are installed beneath the kitchen sink in the cold water supply line and filter all cold water. Line bypass carbon filters are installed in the kitchen under the sink attached to the cold water supply line, but a separate faucet is installed at the sink to provide treated drinking water. The regular tap delivers untreated water. The carbon filter lasts longer because only water used for drinking is treated. Point of entry (POE) carbon filters treat all water entering the home. This type of filter is recommended for treating volatile organic compounds (VOCs) that easily evaporate into the air. Because of the installation costs, size of the filter system and frequency of replacement, these are the most expensive filters to purchase and maintain.

Mechanical filters trap solids and suspended particles in the water by straining the water through a filter cartridge made of spun cellulose or rayon. They remove suspended sediment, sand, and soil (or turbidity). The water pressure forces water through the tightly wrapped fibers around a tubular cartridge that comes in all the types that a carbon filter does. These filters come in a variety of sizes and meshes from fine to coarse, with the lower micron rating being the finer. The finer the filter, the more particles are trapped and the more often the filter must be changed. Fiber filters may not remove all contaminants. If taste and odor problems remain, use a carbon filter after the fiber filter. Often these filters are sold in combination with carbon filters. Fiber filters and replacement cartridges range in price from a few dollars to several hundred dollars. A mechanical filter may become clogged if not cleaned or replace periodically. A clogged filter is one cause of a fall in water pressure. The level of total dissolved solids, TSS or turbidity and water usage will determine the frequency of filter cleaning or replacement required to keep a filtration system functioning. Filters can become hosts to bacterial growth, so that the water should be tested regularly for bacterial presence.

Remember, filters do not purify or soften water. Filters only remove some suspended particles and in the case of the carbon filters dissolved organic compounds that cause disagreeable odors and tastes. These filter systems DO NOT remove nitrate, bacteria or heavy metals.

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