Iron and manganese are common elements in the earth’s crust. As water percolates through soil and rock it can dissolve these minerals and carry them into groundwater. Also, iron pipes can corrode and leach iron into a household water supply. Iron is more common than manganese, but they often occur together. While they are not hazardous to health, they pose issues for water taste, odor and color.
Iron exists naturally in rivers, lakes, and underground water. It may also be released to water from natural deposits, industrial wastes, refining of iron ores, and corrosion of iron containing metals.
Iron is generally present in water in the form of Ferrous Bicarbonate (Well water), Iron sulphate (Waste water from steel mills or other industrial or mine drainages) and sometimes as organic Iron compounds (leached from vegetation).
The combination of naturally occurring organic material and iron can be found in shallow wells and surface water. This water is usually yellow or brown but may be colorless.
Manganese is generally removed by aeration and pH correction. Manganese oxidizes differently from Iron and in some conditions may actually hinder iron removal. In these cases, we use coagulant and flocculent to precipitate manganese.
Iron and manganese are not health concerns in drinking water. Instead, they both have secondary or recommended drinking water standards because they cause aesthetic problems that make the water undesirable to use in the home and may cause a bitter metallic taste that can make the water unpleasant to drink for both humans and farm animals.
Iron can also cause an orange or brown stain in sinks and in the laundry. Manganese often results in a dense black stain or solid. For these reasons, as a part of EPA’s Secondary Drinking Water Regulations, it is recommended that drinking water have no more than 0.3 mg/L (or 0.3 parts per million) of iron and less than 0.05 mg/L of manganese.
WETS uses aeration followed by filtration, with possible addition of a coagulant and flocculants. Ferric form usually precipitates at high pH.
WETS can perform a pilot study to determine the best method to be used to bring iron and manganese to the desired levels. Often, arsenic will be present in combination with iron and/or manganese. When iron and manganese are in the water, our dual filter media with proper quantity of coagulant and flocculent will precipitate both iron/manganese and arsenic. Our pilot study will economize on the chemical dosing and also help on getting TCEQ approval. Our solutions are unique for each plant as we don’t offer an off-the-shelf product.