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.