Co-flow and Counter Flow Systems

Loading
Fill the vessel to 1/2 its height with water to ensure proper settling of the resin and avoid resin damage. Adjust water flow via drain valve to maintain the water level. Load the correct resin volume into the vessel. Backwash the resin bed for 30 minutes at an expansion of 80 – 100 % to remove fines and classify the bed. Let bed settle and drain to 10 cm (4 inches) above top of resin bed. Mark resin level in sight glass. This mark can be used to detect resin loss in long term operation. Make sure the resin level conforms to the plant design. For water or air hold-down counter-flow plants, it is important that the resin level is above the central regenerant collector to avoid turning of the bed.

Commissioning
Proceed through a normal acid and caustic regeneration procedure. If supplied in the exhausted form, a double or triple regeneration is recommended. This does not mean going through the whole regeneration cycle two or three times, but instead ensuring that double or triple the amount of chemical is applied. This may involve refilling the chemical measure. 

Carry out the displacement rinse according to the normal procedure and rinse to the specified conductivity.

New resins should be rinsed to drain separately when regenerated for the first time. Only apply recycle mode in subsequent regenerations to prevent contamination of both the resin bed and the treated water with residual organic matter that may be present on newly manufactured resin.