AFM® is a production of Research by Dryden Aqua over the last 30 years in association with the UK Government and European Commission under the Life Environment initiative LIF02/ENV/00146. AFM® only activated AFM®. The glass is processed to a high standard by Dryden Aqua, it then progresses through a physical and chemical stage to increase the metal ion catalytic activity, and density of surface hydroxyl groups. Surface area is also increased from 3000m2 per tonne to over 10million m2 per tonne for surface adsorption reactions.  

AFM® has been certified by the UK regulator for drinking water treatment and has been independently verified by IFTS in comparison to sand and other filter media in Europe. It is confirmed that AFM® is 50 % better than sand and twice as good as any other glass media.

AFM ( grade 1) is a mechanical filtration media that will remove in excess of 97% of all particles in the water down to 5 micron with a bed depth of 1200mm and flow velocity of 20m/hr. Grade 0 AFM will filter >97% of all particles in the water doen to 1 micron with no pre-coagulation or flocculation.  At slower water flow rates and with the application of coagulation / flocculation nominal filtration below 1 micron is a practical proposition with AFM.  A performance previously only achieved by use of membranes.  AFM will not biofoul,  the bed will not coagulate and there will be no worm-hole channelling.  The activated surface of AFM will selectively adsorb organics and selective heavy metals ( ferric, manganese chromium) and metaloids (arsenic) from the water. AFM does not have the capacity of activated carbon, but every time it is back-washed with water it is regenerated.  AFM will remove selected priority substance from water by adsorption,  we are conducting research on AFM to improve the selection molecular sieve adsorption of different chemicals from water.

AFM is a great deal more than a substitute for sand ,  it is 100% sustainable, will last for the life of the filter, it will perform at least 50% better and it will adsorb organics.  Te UK Carbon trust and Oakdene Hollins consults to te water industry confirm an ROI under 18 months.

Grades & Particle size distribution

The particle shape of AFM® is controlled to maximise surface area and minimise pressure differential bed lensing effects. The particle size distribution is also controlled to within very tight tolerance.  We can control the sphericity and uniformity coeficient to maximise of particle filtration. While a high spericity is beneficial for sand this is not necessarily the case for AFM. The higher the uniformity coeficient the better the filtration performance,  but the greater the risk of  bed compaction and lensing.

Operational criteria

Run-phase water flow 1 – 30 m/hr

Air purge 50 to 100 m/hr

Back-wash 45 to 55 m/hr for 5 minutes, or 20 % bed expansion

Specificationgrade 0grade 1grade 2grade 3

particle size (95%)

0.25 to 0.50

0.4 to 1.0

1.0 to 2.0 2.0 to 4.0

effective size

0.32

0.46

1.3 2.6

hardness

>7 mohs

>7 mohs

>7 mohs >7mhos

sphericity

>0.7

>0.7

>0.7 >0.7

roundness

>0.6

>0.6

>0.6 >0.6

uniformity coeficient

1.4 - 1.7

1.5 to 1.7

1.5 to 1.7 1.5 to 1.7

aspect ratio

2 - 2.4

2 - 2.4

2 - 2.4 2 - 2.4

purity

>99.99%

>99.95%

>99.95% >99.95%

specific gravitry (grain)

2.4 kg/l

2.4 kg/l

2.4 kg/l 2.4 kg/l

embodied energy

<72kw/tonne

<65kw/tonne

<50 kw/tonne <50 kw/tonne

Bulk bed density

1.28

1.25

1.23

1.22

Chemical Composition by % ( all grades)

Silica

70

Calcium

10

Magnesium

1

Lanthanum

2

Sodium

8

Cobalt

0.016

Aluminium

1.5

Lead

<0.005

Antinomy

<0.001

Mercury

<0.0005

Arsenic

<0.0001

Titanium

0.1

Barium

0.02

Rubidium

0.05

Cadmium

<0.0001

Iridium

0.05

Chromium

0.15

Platinum

0.0001

No metal ion leaching between pH4 and pH10

Independently tested-checked-certified

AFM® has been tested against sand by Scottish Water and Lyonnaise, and confirmed to be twice as good as the best available sand. AFM® checked by WRC-NSF and certified by European Authorities. French NGO national government organisation confirmed AFM® far superior (50 % better) in performance to crushed glass and has been independently verified by IFTS.

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