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Research & Development
AFM® is the product of more than 30 years of research and development by Dr.Howard T Dryden. The research was based
on a PhD on aluminosiclicate zeolitic sand clinoptilolite for the selective ion exchange filtration of recycled water for
intensive closed (RAS) aquaculture systems. Sand rapidly biofouls and coagulates, which results in bio-dynamic instability
of the sand bed followed by transient channelling of un-filtered water passing into the product water. This happens in all
sand filters, and in aquaculture it will lead to fish mortalities. In drinking water, it leads to disease. AFM® (an activated filter
media) was developed as a means of resolving the deficiencies incumbent with all sand filters. The technology is perfectly
adapted to any type of sand filter or application, ranging from; drinking water to industrial process water. AFM® will improve
performance, reduce risk and stabilise the systems, by providing a predictable repeatable and sustainable performance.
Dryden Aqua guarantee statement
The performance of AFM® has been independently verified by IFTS, Dryden Aqua guarantee that after 10 years the
performance of AFM® will be within 10% of the “as new performance” measured under ISO standard conditions. AFM®
must be used in accordance to Dryden Aqua specifications.
There will be no reduction of performance or AFM® properties when the media is back-washed at a rate that fluidises the
bed by a minimum of 20% for a period or 5 minutes or until the water runs clear. AFM® installed on systems 20 years ago is
still performing to specification.
Nicola Sturgeon, first minister for Scotland and Howard Dryden CEO of Dryden Aqua, in the AFM®
production facility in Edinburgh