What is Birm media? Application of Birm for iron removal in water purification
Birm: Economical Iron/Manganese Removal. The following product information is based on documentation from Clack Corporation, manufacturer of Iron/Manganese reduced by Birm
What is Birm?
Birm is actually an acronym for “Burgess Iron Removal Method”. Birm Filter Minerals are manufactured by impregnating Manganese salts into a core made of Aluminum Silicate. This granular filter media is black and has a moderate density.
Technical characteristics of Birm
| Filtration speed | 3.5 – 5gpm/sq. ft. (≈8.6 – 12.2m3/h.m2) |
| Backwash flowrate | 10 – 12gpm/sq. ft. (≈24.5 – 29.3m3/h.m2) |
| Density | 40lbs/cu. ft. (≈1.56kg/lít) |
| Average life expectancy | 8-10 năm |
| pH requirement | 6.8 – 9.0 |
| Dissolved oxygen level | 15% |
How does Birm work?
Dissolved Iron and Manganese cannot be removed by direct filtration. They need to be oxidized and precipitated into larger “flocculations” so that they can be removed by the filter.
Birm acts as an insoluble catalyst enhancing the reaction between Dissolved Oxygen (D.O.) and Iron/Manganese. After being oxidized, Birm filter media removes contaminants from water. Birm is an efficient and economical method for removing dissolved iron and manganese compounds from raw water. It can be used in feed water treatment systems by gravity or pressure filtration. Birm acts as an insoluble catalyst to enhance the reaction between dissolved oxygen (D.O.) and iron compounds.
Eventually, oxidized solids will begin to coat the surface of the filter media and will need to be backwashed or vigorously rinsed to remove any sticky residue and clean the filter media back to its original state.
Like all other Iron filters, Birm must be backwashed to the manufacturer’s specification. A weaker backwash water supply than required will shorten the life or cause the system to stop working.
Pretreatment recommendation
Birm can be a strong enough oxidizing agent for iron levels up to 3 ppm. If the Dissolved Oxygen level is below 15%, the addition of a sprinkler system, aeration system, aeration system, or an air ejector system is required to increase the oxygen level to make the iron reduction system more efficient. The addition of oxygen gas along with a sufficiently large retention time of 3 minutes of exposure will significantly improve system performance.
Birm’s physical properties provide an excellent filter material that can be easily cleaned by backwashing to remove precipitates. Birm is not consumed in the iron removal operation and therefore offers a huge economic advantage over many other iron removal methods.
Unlike Greensand or Pyrolox, Birm should NOT be chlorinated. Chlorination greatly reduces the effectiveness of Birm and at high concentrations can deplete the catalytic coating or melt the Birm grain.
When using Birm for iron reduction, it is essential that the water does not contain oil or hydrogen sulfide. Organic matter should not exceed 4-5 ppm, and D.O. The content must be at least 15% of the iron content with a pH of 6.8 or higher. If the inlet water has a pH less than 6.8, soluble chemicals such as Clack Corosex, Calcite or soda ash can be used to raise the pH.
Clack’s Birm can also be used to remove manganese with the same reliability as iron removal. In these applications, the treated water should have a pH between 8.0-9.0 for best results. If the water also contains iron, the pH should be below 8.5. High pH conditions can cause the formation of colloidal iron that is difficult to filter out. All other conditions remain the same for manganese or iron removal.
Advantages of Birm
- No need to add chemicals to purchase to maintain oxidizing capacity.
- No need to regenerate.
- The iron removal efficiency is very high.
- Just backwash periodically.
- Durable material with long life and wide temperature range.
- Long material life with relatively low consumable losses.
- Wide temperature performance range and extremely high iron removal efficiency.
