Activated Filter Media

What is AFM®?

AFM® Activated Filter Media is a direct replacement for sand, doubling the performance of sand filters without the need of additional investments in infrastructure. AFM® resists biofouling, biocoagulation and transient wormhole channeling of unfiltered water and outlasts all other filter media.

AFM® is a highly engineered product manufactured from a specific glass type, processed to obtain the optimum particle size and shape. It is then exposed to a 3-step activation process to become self-sterilising and to acquire superior adsorption properties. During activation, the structure and the chemistry of the glass are modified.

AFM® benefits at a glance

  • ... more than doubles the performance of an existing filtration system
  • ... is not subject to biodynamic instability and will never allow untreated water to pass
  • ... substantially lowers chlorine oxidation demand
  • ... lowers backwash water demand by an average of 50%
  • ... is expected to last for the life of the filtration system
  • ... provides quick return on investment


  • Self-sterilizing surface
  • Increased surface area
  • High negative surface charge
  • Self-sterilizing surface

    Unique 100% bio-restistant filter media

    When in contact with water flowing through the filter, a small amount of free radicals (O and OH) are formed on the surface of the grains. Thanks to their strong oxidation potential, free radicals protect AFM® from colonisation by bacteria and fully prevent the formation of biofilm.

  • Increased surface area

    Superior mechanical filtration

    Our patented activation process creates a mesoporous structure to strongly increase the surface area (m2) of AFM®in contact with water. This feature enables AFM® to mechanically capture more particles than sand and other glass filter media.

  • High negative surface charge

    Advanced electro-static filtration

    Our activation process strongly increases the negative electrical surface charge of the glass. Like a magnet, positive and dipolar charged particles going through the filter are attracted by the AFM® grains

Excellent performance of AFM® in comparison with quartz sand and other glass filter media

AFM® comes with important certifications such as NSF/ANSI 50, NSF/ANSI/CAN 61 by WQA for swimming pools and drinking water applications, HACCP, UK DWI and others. AFM® has been independently tested by IFTS Institute de la Filtration et des Techniques Séparatives in France in 2014 and its superior performance over quartz sand and other glass filter media was confirmed and and is documented in the the 2014 IFTS Report available below. AFM® more than doubles the performance of a quartz sand filter and it performs multiple times better than all other glass filter media tested.

What makes AFM® so effective?

1. Clean, carefully selected glass
AFM® is only made from pure green and brown glass which have the necessary metal oxides to help make AFM® self-sterilising.

2. Ideal hydraulic properties
The raw material is ground into the optimal grain size and shape, crucial for the outstanding hydraulic properties of AFM®.
No dangerous glass splinters are allowed to be present in the filter material. Our manufacturing process is ISO certified.

3. Activation process
The AFM®activation process creates a mesoporous structure with a huge catalytic surface area for greater adsorption and catalytic reactions. Hydroxyl groups on the surface give AFM® a strong negative charge, known as the zeta potential, that attracts heavy metals and organic molecules. In the presence of small amounts of oxygen or oxidising agents, the catalytic surface generates free radicals that make AFM® self-sterilising.

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Contact us

Dryden Aqua Ltd
Production, Research & Development
Butlerfield Ind. Est Bonnyrigg
EH19 3JQ
United Kingdom
Phone: +44 1875 822222