Filter media

Overview of various raw materials

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Updated on: 03/24/2020

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Granulated activated carbon

Activated carbon is a widely used filter medium, which is used in different variants. For drinking water treatment these are loose granules - for example in the cartridges of table can filters - or block filters. Poured loose activated carbon granulate filters particles and undissolved solids mechanically like a sieve or sand filter. Due to its porous, brittle structure, activated carbon also has a very large surface area. Even particles with a diameter of less than 1 mm have a surface area of several square metres. As a result, activated carbon can also bind or convert dissolved substances such as chlorine or organic impurities that impair taste and smell. This is known as adsorption, i.e. they attach themselves like a magnet or catalytic filtering, by conversion.

However, compared to sintered activated carbon block filters, the performance of granulates is severely limited because the water only flows around the granulate. In addition, when the capacity of the carbon surface is exhausted, a filter with activated carbon granulate can also "bleed out", i.e. impurities and pollutants are released back into the fresh water and the filter effect collapses. 

Activated carbon block filter

In contrast, the efficiency of an activated carbon block filter is many times higher. While water only rinses around the activated carbon granulate, in the block filter it is forced to penetrate it by means of water pressure, which results in a considerably higher filter performance. Block filters have an enormous filter fineness of up to 0.45 µm (for comparison: a human hair has a diameter of 100 µm) with a high adsorption effect. A further advantage of the block filter is that it does not release any impurities into the fresh water even when its filtering capacity is exhausted. The pores close and the flow rate is greatly reduced. Activated carbon block filters, as also offered by Alb Filter, are installed directly at the water extraction point and filter not only solid impurities, but also microorganisms, pesticides, various heavy metals and medication residues.

Ultrafiltration

Ultrafiltration is a purely mechanical filtration technology with hollow fiber membranes that offer an extreme filter fineness of down to 0.02 µm, i.e. everything larger than 0.02 nanometers is retained. For comparison: a human hair has a diameter of 100 µm. This means that pathogens such as viruses and legionella can also be reliably retained. Ultrafiltration is therefore being used more and more frequently in drinking water treatment. In ultrafiltration, the water to be purified flows at low pressure through the hollow fiber membrane and is thus purified. Activated carbon block filters, such as those offered by Alb Filter, are installed directly at the water intake point and filter not only solid impurities, but also microorganisms, pesticides, various heavy metals and medication residues.