To work out the best way to remove iron from your water supply, you need to know what type of iron contamination you’re dealing with.
In general, wells can be contaminated with three types of iron:
- Ferric iron: Water that’s cloudy, brown, or orange likely contains ferric iron, which is iron in an undissolved form.
- Ferrous iron: This is dissolved iron with a slightly different molecular structure. It won’t be detectable by sight, but may still give off a noticeable odor and taste. When left exposed to oxygen, ferrous iron becomes ferric.
- Bacterial iron: When a well contains high levels of iron as well as bacteria, those nasty microorganisms can bind with iron to produce bacterial iron. This is a highly noticeable red slime that can take over a well and make it undrinkable.
The best way to find out what kind of iron is in your drinking water is to perform a well water test. Here are the 4 major methods for removing ferric, ferrous, and bacterial iron:
Sediment filters are used as one stage in a whole-house water filter for well water. But they can also be used alone to reduce levels of iron in a water supply.
Among the cheapest, yet most effective whole-house filtration device methods, these devices work by physically blocking undissolved particles from moving through the filter – things like rust, sand, silt, and iron.
Exactly what a sediment filter is able to remove depends on the micron rating of the cartridge. This is the size of the pores in the media, above which contaminants won’t be able to make it through. Ratings usually range between 30 – 5 microns.
Due to the way that they filter contaminants, sediment filters are not able to remove dissolved matter, unless they also contain activated carbon or some other specific media.
Sediment filters reduce: Ferric iron
KDF (Kinetic Degradation Fluxion) filter
Another common component in whole-house systems, KDF filters work by using a combination of metals like copper and zinc, which act as a catalyst in water.
As a result of this electrochemical reaction, dissolved iron in the water supply converts to an insoluble form and is then exchanged with electrons in the filter media. KDF filters retain this insoluble iron while letting the rest of the water flow past.
KDF filters reduce: Ferrous iron
Air injection filter
Also known as oxidizing filters, these devices work in a similar way to KDF filters. By introducing a pocket of air into the water tank, air injection filters cause ferrous iron to oxidize into insoluble ferric iron, which can then be physically filtered from the supply.
Air injection filters reduce: Ferrous iron
When a film of bacterial iron invades a well, chemical disinfection is the best method of removing it.
Often carried out by professionals and referred to as shock chlorination, a large amount of chlorine is introduced throughout the well system to remove bacteria. After this, the remaining iron can then be filtered using one or more of the other methods listed on this page.
If bacterial iron or other types of microorganisms are a common problem in the local environment, then well owners may choose to incorporate chlorination as a regular part of their water treatment system. A carbon filter helps to reduce any chemical taste or smell from the faucet.
Chlorine treatment reduces: Bacterial iron