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Organic Scavengers Continued...
Surface waters are often
typified by low hardness and conductivity and high levels
of organics. The organics are the result of the breakdown
of organic materials and an example of this type of water
supply would be from peat moorland. Colouration is also
often associated with these types of water supplies.
The organics present in
some feed waters may have a detrimental affect on water
treatment plant. For example, some types of anion resins
employed in demineralisers may become irreversibly fouled
with organics leading to loss of capacity and failure to
rinse down to quality following regeneration. Organics are
also particularly fouling of reverse osmosis membranes.
To prevent organic fouling
an organic scavenger is sometimes employed upfront of susceptible
water treatment plant. Typically macroporous and/or acrylic
type 1 strong base anion resins are used to remove the organics.
Removal efficiency is dependent upon the nature of the organics
and operation is normally typified by long contact times.
The resin has a finite
capacity for scavenging and is generally regenerated based
on time spent in service. On exhaustion regeneration is
carried out using a solution of saturated brine. In some
cases low levels of caustic might be added and the regenerant
solution heated to improve regeneration efficiency.
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