Iron in water at elevated levels is one of the most common elements that cause a problem with the quality of well water. Besides water hardness problems, iron is the next most frequent problem makers. From cloudy drinking water to orange-brown deposits on toilets, bathtubs, and sinks, iron leaves traces, stains, and an unpleasant taste in water.
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How does iron cause damage to your household?
The iron deposits will stick to the walls of the pipes, and the deposits that have formed over the years will reduce the cross-section of the pipes, reducing the water pressure in the installation.
Water with increased iron content will spoil the taste of your favorite coffee, tea, or soup and leave slightly orange marks on all items in contact with water. Even in smaller concentrations, iron can cause constant and very irritating problems.
Appliances in contact with iron from the water
Any device that is connected to water with an increased iron content will inevitably be damaged over time due to the formation of iron deposits in it. Brownish-orange marks will appear on toilets, sinks, faucets… Bathtubs and showers will lose their shine and color very quickly. Even dishes and laundry washed in water with an increased iron content will over time lose their shine and color and acquire a slightly reddish tint. A good water system for iron removal can solve all these problems for good.
Drinking water with increased iron content
Iron from the water leaves a metallic taste in the mouth, and it doesn’t even look visually appealing to drink due to the creation of turbidity and iron deposits in the glass. It also gives the water a sharp and distinctive smell. This means that well water, depending on the form and concentration of iron, will have brown, red, orange, or yellow color when it is poured into a glass. Any beverage made with this water (tea, coffee, juice) will also have that distinctive metallic taste. Even cooking pasta or vegetables in iron-rich water will change their true, natural color and give them that metallic taste. One of the most important thing is that iron deposits are an ideal place for iron bacteria growth.
Iron deposits in pipes
The iron from the water slowly sticks and settles on the pipe walls, hot water tank, toilet tanks. This slowly reduces the cross-section of the installation and creates an increasing resistance to the flow of water. This reduces the water pressure in the installation, reducing the efficiency of all devices connected to the installation. Iron bacteria in particular can cause pipe blockages. They leave a thick, slimy, brown residue that sticks to the pipeline. This residue also provides ideal conditions for the development of iron bacteria. Any device connected to this type of water will have reduced operating efficiency and service life.
Iron effects on skin and hair
Just as water with an increased iron content leaves traces on dishes and sanitary ware, it also leaves traces on the skin and hair. Showering with this kind of water can cause unwanted hair color and a damaged appearance. Bathing in such water can give the skin a reddish tint.
Iron in drinking water – is it dangerous?
Iron in water has no health side effects for the human body. Iron mostly affects the aesthetic appearance of water, and gives an unpleasant taste and deposits, reducing the comfort of living in your household.
Ferric iron in water – the undissolved iron
Iron in water can be in the form of soluble ferrous iron and ferric iron. The ferrous iron form is when the iron is dissolved in water, and the ferric iron form is when the iron is in an insoluble form, i.e. in the form of a precipitate. Both, ferrous iron and ferric iron make similar problems.
Removal of undissolved iron from water
As there are different forms of iron in water, different amounts of iron in water, the choice of a right water system for iron removal is very important to solve your iron problems in the long term.
Mechanical filters can remove iron that has already settled in the water. Filter housings with filter inserts of different porosities can effectively remove mechanical impurities in water, as well as already precipitated iron. Iron that is dissolved in water cannot be removed by mechanical filters, and they will not solve the problem of iron traces, nor the metallic taste of the water.
Ferrous iron in water – the dissolved iron
When it comes to ferrous iron in the water, it is not noticeable at all during pouring and the water is completely clear. Only when the water is exposed to atmospheric conditions and oxidation of iron occurs, it changes to an insoluble form, i.e. the appearance of sediment. Although dissolved iron is not immediately visible, it still forms iron deposits and gives a metallic taste to water. Dissolved iron is most often found in deeper wells and waters with a low content of dissolved oxygen.
Removal of dissolved iron from water
Ion exchange water softeners can effectively remove dissolved iron in water but only at lower concentrations. The main purpose of a water softeners is to remove limescale, the process of replacing Sodium ions with positively charged ions from the water, such as Calcium and Magnesium. Since Iron is also a positively charged cation, it will be replaced by a Sodium ion and attached to the ion exchange resin. However, if there are higher concentrations of iron, it can damage the softening ion exchange resin in water softeners. It can lead to poor ion exchange resin regeneration and lower water softener capacity. In high concentrations of iron in water, even a water softener requires iron removal before it.
Devices with special iron removal filtering media
One of the most effective ways to remove dissolved iron from water is to convert it into an insoluble form and filter the resulting precipitate. Greensand filter media in contact with iron oxidizes it and turns it into an insoluble form. The insoluble form of iron is then filtered out on the media and the water is free from iron.
Devices with Greensand filter media can work in two ways, and the appropriate one is chosen based on the concentration, operating conditions, etc…
Greensand filter media requires periodic regeneration or continuous dosing of an oxidizing agent.
Solution to iron free water – iron removal filters
Iron removal filter are devices for removing dissolved iron and manganese from water, which in larger quantities can have a very negative effect on many technological processes, especially in the food industry, textile industry, or make the water very unpleasant to use in your home.
In some cases and higher iron contents in water it has to be removed before other water purification systems – like water softeners.
The principle of operation
Iron removal filters are filled with a special filter media that catalytically oxidizes dissolved iron in the form of insoluble ferric iron, as well as manganese in the form of its insoluble oxide and simply filters them on the media.
If the water contains sufficient amount of dissolved oxygen, then a filter media is chosen, with which the water is simply filtered on the iron filter and iron and manganese are removed from it.
If the water does not contain enough dissolved oxygen (which is usually the case with water from deep wells), two modes of operation of the iron filter are possible. One way is to add an oxidizing agent such as potassium permanganate or a form of chlorine. The oxidizing agent is added with a suitable dosing pump coupled to a flow meter to maintain the same concentration regardless of flow rate changes.
Another way is to periodically regenerate the iron filter media by regenerating it with an oxidizing agent.
Through periodic backwashing, the filtered iron and manganese sediments are simply washed out from the iron filter.
Arsenic and hydrogen sulfide
In addition to iron and manganese removal, iron filters can very effectively remove arsenic and hydrogen sulfide (H2S), which, even in extremely small amounts, gives the water an unpleasant smell like a rotten egg.
Who am I?
I am working as a water treatment technical manager and I have more than 25 years of practical experience in water purification.
Water purification expert
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