Arsenic in your drinking water may damage your health. Because arsenic in household well water is usually dissolved from natural rock in the aquifer, water treatment is the only way to eliminate it. Arsenic in well water occurs in two different forms, “arsenic-III” and “arsenic-V”. Arsenic-III is more toxic to humans and is more difficult to remove than arsenic-V. Because both arsenic forms are found in some ground water, home treatment systems (like the one described below) should remove both.
If you have tested your water and the arsenic level is greater than 10 parts per billion (ppb), you should re-test to confirm the result before obtaining a treatment system. When re-testing for arsenic, also test the pH, phosphate, silica, hardness, iron, manganese and sulfate levels. The pH, phosphate and silica levels will help your water treatment professional estimate the life of arsenic treatment media, and the hardness, iron, manganese and sulfate levels will determine whether a pre-treatment step is necessary.
Arsenic removal from water requires special adsorption media. Granular ferric oxide, titanium and hybrid media that contain iron-impregnated resin are all highly effective, but there are differences in media life. Before choosing a treatment technology, homeowners should ask water treatment providers to estimate the number of days that media can remove arsenic based on their water usage and water test results. The media are either contained in tanks for whole-house treatment or in cartridges for point-of-use (POU) treatment. Whole-house treatment is intended to treat all water for the house. The POU treatment system is installed at one location, such as a kitchen faucet, that provides water for drinking and cooking.
The whole-house treatment system usually is the preferred treatment technology for arsenic removal, and its media typically lasts for two to three years. Given the higher initial cost of whole-house system, homeowners can consider a POU system that would provide enough water for drinking and cooking in an average household. However, some arsenic exposure may continue from drinking from other faucets, bathing, showering and brushing teeth. The media in POU systems typically lasts for one year.
Some well water may need to be pre-treated before it goes through the arsenic treatment system to extend the system’s life. We can provide information and equipment for pre-treatment. The pre-treatment step is generally recommended when water has one or more of the following test levels:
Iron higher than 0.5 parts per million (ppm)
Sulfate higher than 100 ppm
Manganese higher than 0.05 ppm
Hardness higher than 300 ppm