Water is something we should drink plenty of every day for good health, but these days many of us are worried about finding clean water. Sometimes well water contains arsenic, a potentially poisonous chemical. When homeowners want to make sure they avoid that unwanted addition to their water supply, they rely on the use of an arsenic water filter. In order to purchase the proper filter a homeowner needs to review some facts that relate to basic chemistry.
The Two Types of Arsenic Water Filters
Arsenic dissolves in water. Dissolved in water a molecule of arsenic can take on one of two forms. It can become Arsenic V, an inorganic compound called arsenate, or it can become Arsenic III. The latter chemical, one called arsenite, is an organic compound. Filter membranes, as used during the process of reverse osmosis, have the ability to remove both arsenic V and arsenic III. Filter cartridges containing KDG/GAC can be counted on for the removal of only one type of arsenic—inorganic arsenic (Arsenic V).
Determining the Need for Arsenic Water Treatment
The homeowner cannot rely on his or her sense of smell or taste to detect the presence of arsenic in tap water because it is odorless and doesn't have a distinct flavor. By the same token, water that contains an appreciable amount of arsenic will not develop a distinctive color. Therefore a homeowner must turn to a reliable testing service when unsure about the presence or absence of arsenic in a home’s tap water.
Yet that homeowner should not invest in an arsenic water filter after word of a single test result. Changes in the environment can add to or diminish the level of arsenic in a home’s water supply. Thus each homeowner should hear about the results from a minimum of two tests before reaching any conclusion about arsenic in a home’s tap water.
Choosing A Water Filter To Remove Arsenic
If test results show that the tap water in a home contains arsenic, then the homeowner should plan to purchase an arsenic water filter. The homeowner must choose between a point of use filter and a whole house filter.
The point of use filter insures removal of arsenic from a single location within a building. If placed in the kitchen, the point of use filter provides those in a home with a source of arsenic free cooking and drinking water.
By contrast, the whole house water filter guarantees the delivery of arsenic free water to every tap within a given home. The typical whole house filter has four essential parts—a water meter, a pretreatment oxidizer, a component that actually removes the arsenic and a place for storage of the purified, arsenic free water.
The whole house filter subjects the home’s water supply to a process known as oxidation. Only after the water has been exposed to an oxidant does it pass through a membrane, the “core” of this arsenic water filter. The filter catches the particles of arsenic and allows the arsenic free water to flow into some sort of “holding tank.” When using a whole house filter the home's plumbing system should contain lead free or copper pipes to avoid corrosion.
By: Lars Garrett
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