With a proportion of 4.7%, iron is one of the most common elements in the Earth’s crust. The legally established maximum allowable concentration of iron in drinking water is 0.3 mg/L. This limit is primarily set for aesthetic reasons — sediment formation and orange staining.
At concentrations of 0.5 mg/L and higher, the taste of water changes, and the water becomes turbid, acquiring an orange or brown coloration.
There are various types of filters for iron removal that use different filtration media with specific characteristics. One such filtration media for flow-through water treatment systems is Birm.
Birm is an effective granular material designed for the removal of iron compounds. The name Birm is an abbreviation of “Burgess Iron Removal Method.” Birm media can be used for treating water from both open sources (rivers, lakes, wells) and artesian boreholes.
Operating Principle of a Water Treatment System Based on Birm Filter Media
The system is a column made of high-strength, corrosion-resistant plastic, equipped with an automatic control valve manufactured by Clack Corp. (USA).
The filter is connected to the cold water supply line. Water enters the filter vessel filled with Birm media after preliminary removal of mechanical impurities. Birm acts as an insoluble catalytic medium, accelerating the oxidation of iron from the ferrous (Fe²⁺) to the ferric (Fe³⁺) state using oxygen dissolved in the water.
Ferrous iron is fully dissolved in water. It can be detected through laboratory water analysis, but is difficult to identify visually. When such water comes into contact with air, oxidation occurs and the water acquires a yellowish tint. The simplest method for removing ferrous iron is the use of an iron removal system that converts ferrous iron into ferric iron, which can then be removed by mechanical filtration.
Ferric iron is formed from ferrous iron after oxidation. It becomes heavier, is no longer soluble in water, and settles as a fine-grained precipitate. This negatively affects equipment performance and reduces the service life of appliances and pipelines.
As a result of further hydrolysis, ferric iron forms Fe(OH)₃, which becomes visible, precipitates, and is removed from the water by filtration. This process occurs during backwashing and media expansion.
Unlike other filtration media, Birm does not require chemical reagents for regeneration. Only periodic backwashing with clean water is required, which loosens the filter bed and removes accumulated contaminants. After this process, the filtration system is ready for continued operation. Thanks to the multifunctional electronic control valve, the filter does not require constant monitoring.
The use of Birm filter media is economically efficient compared to alternative iron removal methods.
Conditions for Using Birm in Iron Removal Water Treatment Systems
When using Birm media, it is important to consider that certain conditions must be met for its effective application. The treated water must be free of petroleum products and hydrogen sulfide; the content of organic substances should not exceed 4–5 mg/L; the dissolved oxygen concentration must be at least 15% of the iron concentration; and the pH value must be no lower than 6.8. If the pH is below 6.8, neutralization is required. The level of dissolved oxygen in the treated water can be increased through preliminary aeration.
Birm can also be used for manganese removal. In this case, the pH level should be within the range of 8.0–9.0. If the water also contains iron, it is not recommended to treat water with a pH higher than 8.5, as at elevated pH levels iron compounds may convert into a colloidal form, which is very difficult to remove by filtration.
Chlorination of the feed water significantly reduces the activity of Birm.
Advantages of Birm filtration media:
- does not require chemical regeneration;
- high efficiency of iron removal;
- low operating costs;
- long service life;
- wide operating temperature range of treated water;
- low water consumption during backwashing due to the low weight of the media;
- compatible with standard pumping equipment.
An iron removal system based on Birm media also simultaneously removes mechanical particles up to 20 μm, which are flushed into the sewer during filter backwashing. The service life of the filtration media typically ranges from 2 to 4 years, depending on operating conditions.
FPB Birm iron removal filters have proven themselves as reliable and cost-effective solutions within the budget segment.
In industrial applications, the use of water with elevated iron content leads to frequent equipment failures and deterioration of final product quality. Practically all manufacturers of medium- and high-capacity industrial equipment specify strict limits on iron concentration in feed water. Iron forms rust deposits on heat exchange surfaces, reducing efficiency and accelerating wear. Therefore, iron removal is mandatory for most industrial facilities. Water treatment systems based on Birm media have demonstrated stable and reliable performance over more than 15 years of operational experience.
Physical properties:
Operating conditions:
To obtain detailed information about the technical characteristics and intended use of the equipment, or to select suitable iron removal filters, please call the phone number listed in the Contacts section or submit a request using the form at the bottom of this page.
