Dryden-Aqua AFM

AFM® Activated Filter Media is a direct replacement for sand, doubling the performance of sandfilters without the need of additional investments in infrastructure. AFM® resists biofouling, biocoagulation and transient wormhole channeling of unfiltered water and never needs to be recharged or replaced.

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 increase its surface area by up to 300 times for superior mechanical and electro-static filtration performance.

The activated surface of AFM® is self-sterilizing which prevents bacteria mud-balling, coagulation and channeling of unfiltered water through the filter bed. Activation increases the surface area by up to 300 times for catalysis and adsorption reactions. Similar to activated carbon, the surface nano-structure adsorbs pollutants from the water but unlike carbon, AFM® is recharged by just back-washing with water.

Your benefits at a glance

  • … more than doubles the performance of an existing filtration system without the need for additional investments
  • … is not subject to biodynamic instability and will never allow untreated water to pass the filter
  • … substantially lowers chlorine oxidation demand by up to 50%
  • … 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


AFM® replaces sand in all sand filters

AFM® reduces the biological risk from bacteria and parasites as well as the chemical risk. AFM® does not channel so it is an effective barrier against Cryptosporidium and giardia. AFM® does not incubate or discharge bacteria and will reduce the bacterial load of the product water. Also because of the better filtration performance, there are lower THM concentrations. AFM® also provides an excellent solution to remove metals and heavy metals from water.

AFM® is manufactured in a state-of-the-art hygienic factory designed by Dr. Howard Dryden, CEO and inventor of AFM®. AFM® contains metal oxide catalysts that dissociate oxygen and water to create a zone of high oxidation potential to prevent bacteria growing on the surface of AFM®. In addition, the huge activated surface area has a strong negative charge for the adsorption of sub-micron particles and dissolved organic molecules. This makes AFM® far superior to any other filtration media because AFM® does not need to be replaced and is recharged by a simple back-wash.

Filtration performance:

AFM® 1 filters without flocculation down to 4μ at a velocity of 20m/hr. It retains at least 30 % more organic substances than fresh sand or glass media. In chlorinated systems with optimised coagulation and flocculation with APF and ZPM, a nominal filtration of 0.1 microns will be achieved.
AFM® is bioresistant, it offers no home for bacteria, viruses and other pathogens.

The independent testing laboratory IFTS (Institute of Filtration and Techniques of Separation) tested different glass filter media and sand and approved AFM® to be the best available filter material on the market. It is additional certified with NSF 50 & NSF 61 and therefore approved for drinking and swimming pool water.

Sand is a good mechanical filter but also provides a perfect support for bacterial growth as every grain of sand is colonised by bacteria within a few days. Mechanical filtration is compromised by bacterial nitrification that consumes oxygen from the water, depresses the pH and causes anaerobic coagulation of the sand. Clogging causes channeling of the bed and sporadic release of filtered material and undesireable pathology into the process water.

AFM® is not compromised by bacterial growth and provides stable sub 5μ filtration for reliable mechanical filtration and evacuation, even of Cryptocaryon oocysts, in backwash.

No bacteria means no biofilm in the AFM® filter and no channel formation to disrupt the filter function. The performance of AFM® remains consistently high for 10 – 15 years.

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