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General reports |
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- Drinking Water Treatment
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Cryptosporidium oocysts
removal, problem solved |
click
here |
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Power point presentation
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click
here |
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Schematics for system
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click here |
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From WHO up to 6% of all disease in Europe is related to drinking
water, and half of these cases is due to Cryptosporidiosis. AFM
does not suffer from channelling, so we solve this problem. Also AFM
will remove much more organic matter from the water which results in
lower levels of toxic chlorine reactions products. The potential
health benefits from using AFM are too great to quantify. While AFM
costs more than sand, the operation cost benefits will give a return
in capital in under 18 months, and all you need to do is change the
sand to AFM.
Benefits from AFM
- Single pass filtration irrespective of the
influent water quality, negate the need to use activated carbon,
ozone or UVc
- Better performance than ultra membrane filtration
because it removes dissolved organics. Nominal filtration at 1
micron with organics removal using AFM. Absolute filtration at 0.03
micron with ultra filters but no organics removal.
- Reduce chlorine consumption by up to 80% and virtually eliminate
THM`s, applies to double filtration systems with pre-chlorination
prior to second stage filters.
- AFM does not channel so when used with good
coagulation and flocculation you have a much more effective barrier
to the passage of oocysts than is possible with sand.
- Up to 75% reduction in back-wash water, the
back-wash is predictable over years, unlike sand which has a
variable back-wash reaction.
- Public health and environmental benefits are
huge, sand filters incubate bacteria and pulses macro bacteria floc
as well as iron & manganese and other contaminants back into
the water. AFM filters are stable
- How to use AFM, it is a direct replacement for
filter sand, nothing else in the system needs to change.
- Cost, well it costs more than sand but we are
still dealing with a relatively low cost product which will give a
return in capital in under 12 months.
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AFM will improve water quality |
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The graph on the right shows the back-wash turbidity
profile for sand filters and AFM filters operated by Suffolk & Essex
Water.
When the filters are back-washed the Turbidity against
time profile gives a smooth, predictable and repeatable profile with
AFM. The sand back-wash profile was more erratic.
The area under the curve gives the amount of waste
matter back-washed out of the filters. confirms that AFM is removing
25 to 30% more waste from the water than sand. This data refers
to new sand and AFM filters. We find that as sand ages the
performance continues to deteriorate whereas AFM stays the same or can
actually improve. After about 6 months or more partial channelling of
water can start to occur with sand filters, leading to the potential
passage of oocysts and reduction in water quality. |
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Key Points |
- AFM is resistant to biofouling, filter bed performance is therefore maintained
- 30% to 50% more solids removed from the water
- Up to 50% less water used on back-flushing, 100% of waste
released
- Adsorbs and cracks dissolved organics, will decolourise to
some degree
- Adsorbs micron and sub-micron particles
- Lower THM`s because of better filter performance
- Lower flocculent demand
- Improved oocysts removal efficiency
- better iron and manganese removal
- some data suggest good herbicide, pesticide and arsenic removal
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