Arsenic as a Water Contaminant
Arsenic occurs naturally in ground water in many parts of the world. Arsenic diffuse in water through natural volcanic deposits. Well with higher manganese and iron content exhibit higher arsenic content if significantly higher amount of water drawn from the well. Arsenic can also spread in water and contaminate by industrial and agricultural pollution. There are many technologies available for arsenic removal from the water. WETS widely used modified coagulation/filtration technology (popularly known as MCF) as it is more economical. Our pilot study will economize on the chemical dosing and also help client on getting TCEQ approval. Our solutions are unique for each plant.
Inorganic arsenic appears in trivalent (arsenite, As+3) and pentavalent form (arsenate, As+5). Arsenite has no charge which makes it more difficult to remove in arsenic water treatment. About third of soluble arsenic in well water is in the arsenite form in US ground water and surface water. Arsenate has a negative charge so it can be readily removed by coagulants. Usually, Arsenite (III) must be oxidized to Arsenate (V) before the treatment. Pre-oxidants such as chlorine, potassium permanganate, ozone, hydrogen peroxide, and ultraviolet light.
Maximum Contaminant Level
EPA established MCL to 10 ppb
Public Health Concern
Arsenic is a naturally occurring carcinogen, which is known to lead to both cancer and heart failure. Exposure to arsenic at high levels poses serious health effects. Arsenite and arsenate readily absorbed in the stomach. Arsenite take much longer time to clear from the body than arsenate. Hence arsenite is more persistent toxin and greater biological threat. In 2001 USEPA lowered the MCL limit of arsenic from 50 ppb to 10 ppb.