Detailed Guide on Iron Treatment and Water Filters That Remove Iron

How does Iron mix with water?

Iron is a common element found in many private water supplies. It generally doesn’t cause problems for municipal water end users, because water treatment for Iron removal is accomplished at the municipal level. Chemical disinfection using chlorine or chloramines will oxidize most or all soluble ferrous Iron into insoluble ferric Iron, which is then typically removed with sediment filtration or settling. Whereas with water drawn from a private water source, the end user, or owner of the private property, is responsible for removing any unwanted Iron.

Soil contains Iron. As rainwater penetrates the soil, it dissolves some of the Iron forming some amount of ferrous and ferric Iron depending on a number of other conditions present. The reaction between water, Iron, and oxygen produces red-water ferric Iron (Fe3). Dissolved ferrous Iron water (Fe2) will initially pour clear. Two forms of Iron may be present in many well water supplies - insoluble ferric Iron or soluble ferrous Iron. When ferrous oxide is present in water, the water may be clear if the Iron is dissolved completely. When water is exposed to oxygen in a pressure tank or air from the atmosphere, it will turn cloudy, and a reddish-brown substance forms as the Iron oxidizes, precipitates out of solution and into suspension (Lee & Stunn, 1960). This is the ferric Iron which does not dissolve in water.

Iron is an important mineral that is essential in the body. It is used to make hemoglobin responsible for transporting oxygen from the lungs to other body parts and myoglobin that supplies oxygen to muscles (Hallberg, 2002). Since Iron is essential for several functions in the body, there is a need to maintain the amount of Iron in the body throughout its uptake, transport, and storage. Iron is controlled during the body processes mentioned previously, but the body has no defined mechanism for actively excreting it (Harrison‐Findik et., al, 2007). The human body does lose a small, but steady, amount of iron by gastrointestinal blood loss, sweating and by shedding cells of the skin and the mucosal lining of the gastrointestinal tract. Hepcidin is a peptide hormone secreted by the body which plays a crucial role in Iron regulation. It controls the storage of Iron in the body and its acquisition. The hormone is primarily a product of hepatocytes and negatively regulates Iron entry into plasma. When there is low Iron entering the plasma, it causes low transferrin saturation, and low amounts of Iron are taken to the developing erythroblast. Decreased hepcidin expression causes increased cell surface and increased Iron absorption (Cook et al., 2003). This regulation is made to ensure Iron is taken as needed and avoid toxicity.

The deficiency of Iron in the body can cause anemia, especially for children, and lead to delayed psychological development (Camaschella, 2015). It is recommended that expectant mothers take foods rich in Iron to better the unborn child's health. Additionally, breastfeeding mothers are encouraged to take Iron-rich foods to pass the mineral to the breastfeeding babies.

Before purchasing treatment equipment to remove Iron, it is important to understand what type of Iron is in the water (whether ferric or ferrous), on which Iron type the treatment is effective (ferrous, ferric, or both), the result expected, and if construction or reconstruction of the water supply would be more effective or cheaper than long term Iron removal. Another effective solution is to install an Iron filter for well water at the whole house level to reduce or eliminate Iron contamination when present outside the allowable range. If Iron levels are too great in a private well it may be cheaper to dig a deeper well, or a new well at a different location, or get connected to a municipal source, than it would be to treat very high levels of Iron. It is of crucial importance to determine if any Iron Bacteria are present, as any amount of Iron Bacteria will foul most filtration systems.

Ion-exchange water softeners are commonly used to remove ferrous Iron from well water when the amount of ferrous Iron is in the 3-5ppm range, however that is an approximation and the total contaminant load, including other contaminants such as manganese and Hydrogen Sulfide, must be considered prior to purchasing any water treatment equipment. A Full Laboratory Well Water Test is an important first step in home water treatment design. The old adage of “measure twice, cut once” is apropos here. Traditional ion-exchange water softeners are mainly used to remove water hardness; however, they can also remove smaller loads of Iron contamination too (typically 3-5ppm). In the water softening process, sodium ions are exchanged for positively-charged hardness mineral and ferrous Iron ions. If there is ferric Iron in the water, pre-filtering would be necessary to prevent the water softener from becoming clogged with Iron particulates. When water softener systems are used to treat iron, there may be more frequent flushing and softener media resin bed regeneration, than when treating hardness minerals alone. Mechanical sediment filtration can also help remove ferric Iron from water supplies with smaller amounts of ferric Iron. This method applies to insoluble ferric Iron because the sediment filter will allow soluble, clear water Iron to pass through. Heavy amounts of ferric Iron contamination may require settling tanks, followed by mechanical sediment filtration.

Another effective method for smaller amounts of ferrous Iron contamination is catalytic oxidation. It is a method for oxidizing the Iron to form a precipitate and then holding it indefinitely or until back washed to a drain. With this method, a PH of 7 or greater, is beneficial or required, for ferrous Iron removal depending on the media selected. KDF85 media can be used for ferrous iron removal up to about 1ppm, and manganese greensand can be used for about up to 3ppm of ferrous iron. It is important to consider the amount of manganese and hydrogen sulfide present prior to designing a system to treat the water.

Iron is found in many foods and is added to fortified food products. The following foods are rich in Iron and are recommended for those who experience low levels of Iron in the body; poultry, seafood, lean meat, cereals and bread, nuts, raisins, and dried fruits. It is important to note that the amount of Iron intake should be controlled to avoid suffering from the earlier mentioned effects that can impact one’s health. It's not an uncommon practice to use both a whole house treatment option, and then a final undersink Iron reducing reverse osmosis system for achieving clean water containing less than, or equal to the recommended amount of Iron. Some of the best whole house iron removal systems for well water include Iron media filters, chemical injection, ion-exchange, settling, and/or oxidation media. A water test should be performed to identify the types of Iron present and in what amounts, as well as to test for the presence of any amount of Iron Bacteria prior to purchasing any water treatment equipment.