AFM® water filtration for a secure high quality water supply

Aqua solutions Activated Filter MediaA sustainable economy depends on a sustainable environment and the provision of high quality water is essential, not only for human consumption but for all industries, food security and protection of the environment.

Until now sand filtration has been the standard process used for the treatment of water, it represents the primary means of treating most of our drinking water, industrial process water, and for polishing waste water for second use in irrigation.

Sand filters work well, but sand is uncertified and there are performance and stability issues attributed to bacterial fouling which leads to bio-dynamic instability, and transient channelling of unfiltered water through the filter bed and into the product water. Typically, a sand filter will channel for 0.01% to 5% of the time, even when the sand is aggressively back-washed, and sterilised using chlorine, a bacterial problem and channelling will still develop.

A channelling filter will allow unfiltered water to enter the product water and a channelling rate of 0.01% is sufficient to permit Vibrio Cholera bacteria to enter the water distribution network or parasites such as Cryptosporidium, Giardia as well as heavy metals including lead, arsenic, chromium.

AFM is a direct replacement for sand in any type of sand filter. Simply replacing the sand with AFM, will greatly improve performance and stability of the filters. AFM does not channel, so unfiltered water will never enter the product water, and because of this engineered property the security of the water supply is assured. A perfect solution to a difficult problem achieved with no change to the existing infrastructure, and once AFM is in the filters, it never needs to be changed.

What is AFM®?

AFM is the product of 30 years of research and innovation by Dr.Howard T Dryden. The initial research started with zeolite molecular sieve ion exchange sand which developed into the use of glass as the raw material for manufacture of the molecular sieve catalytic filter media AFM.

AFM is a sustainable cradle-to-cradle (C2C) product in keeping with the circular economy, Non Toxic Environment and human health agenda. AFM is initially manufactured by upcycling waste glass. Although it will last the lifetime of the filter, AFM development is ongoing and older product can be reprocessed at any time to incorporate the latest technological advances. Contrast this with sand which at the end of its useful life is dumped into landfill (classed as hazardous waste in some countries) and replaced by new mined sand, further depleting a finite environmental resource.

The Dryden Aqua factory in Scotland can manufacture more than 30,000 tonnes of AFM per year, sufficient to provide clean drinking water to 80 million people. This capacity will be increased as required by building new factories nearer to the source of the required raw materials, i.e. waste glass, in keeping with the C2C principles.

The factory operates in accordance to ISO9001-2008 and AFM is certified under drinking water regulations REG31, NSF50, NSF61. AFM is even food grade approved HACCP and verified by IFTS to be 10 times better than a high quality sand at removing sub 5 micron particles.

Benefits include:

  • Lower running costs & better performance- AFM filters at least 30% better than sand and 10 times better at removing sub 5 micron particles (independently measured by IFTS). A return in capital can be expected within two years.
  • AFM will last for the life of the filters- should never need to be changed (sand replacement is normal every 3-5 years).
  • Lower consumption of chemicals- AFM performs better than sand, so less flocculant is needed (up to 40% saving) and the product water has a lower chlorine oxidation demand, (up to 80% less chlorine).
  • Lower disinfection by-products- AFM will reduce harmful disinfection by-products (THM’s) because we use considerably less chlorine.
  • Bacteria removal - AFM is the only filter media able to consistently and reliably remove Cryptosporidium, Giardia, Vibrio Cholera and Legionella bacteria from water, which are known to be the source of sickness and sometimes death in millions of people worldwide
  • Ferric, arsenic, chromium, lead & manganese- AFM is the perfect filter media for the sustainable control of heavy metals and metalloids.
  • Priority substances- AFM will effectively remove some priority substances. Pre-treatment research is being conducted to enhance the performance and expand the range of priority substances that can be removed.

Applications of AFM?

AFM is the chosen filter media in more than 100,000 installations around the world including:

  • Municipal drinking water plants, ground water and surface water
  • Municipal Sewage Treatment Plants, tertiary treatment of effluent
  • Salt water desalination, pre treatment prior to membranes
  • Industrial users
    • Petrochemical & Chemical , provision of clean water and removal of oil
    • Pharma & Bio-chemical
    • Food & Beverage producers
    • Textile
  • Aquaculture
  • Swimming pools

The pre-treatment of water with AFM prior to reverse osmosis membranes offers significant advantages over the more conventional UF or multimedia options. The fact that AFM will not support bacterial colonies or biofilm, helps reduce biofouling of the membrane. AFM will also remove substances such as silica from solution, which UF, in spite its superior mechanical filtration performance, is unable to perform. This helps prevent scaling on the membrane. As both biofouling and scaling involve the use and subsequent disposal of fairly aggressive chemicals AFM will help to reduced operating costs and increase membrane life.

What makes AFM®so effective?

  1. We use predominantly green container glass as it has the correct chemical and structural properties for our activation process.
  2. Particle shape and size distribution are critical for the best fluid hydraulics and solids retention. For example, solids can easily push their way through glass bead filter media but with a sub-angular AFM media, the grains lock together to prevent the solids slipping through.
  3. The AFM activation process increases the surface area available for adsorption by 300 times to over 1‘000‘000 m2/m3. This means 300 times more surface area for the adsorption of dissolved organic pollutants. The huge surface area coupled with the electrostatic attraction of the negative zeta potential makes AFM the best filtration media for potable water treatment.

Dryden Aqua is a Scottish based company established in 1980 specializing in water quality and innovative treatment technology. Dryden Aqua is exclusively represented in China by Aqua Solutions Ltd.



Contact Aqua Solutions Today


Design Services

We offer an initial design and consultancy service to help you get your project up and running.

aqua solutions design

Equipment Supply

Equipment is supplied against an agreed delivery schedule as required to meet your project needs.

aqua solutions supply

After Sales Support

Once your project has been installed and commissioned we will still be on hand to support.

aqua solutions support

Latest News