Florida Drinking Water Operator "B" Practice Test

What is the correct order of operation in an ion-exchange softening plant?

1. Backwash, rinse, service, brine

2. Service, brine, rinse, backwash

3. Service, backwash, brine, rinse

4. Rinse, service, backwash, brine

The correct answer is: Service, backwash, brine, rinse

In an ion-exchange softening plant, the correct order of operation is service, backwash, brine, and rinse. During the service phase, the ion-exchange resin is engaged in the softening process, removing hardness ions from water. This is the phase where the system is in its primary function of softening water. Following the service phase, backwashing occurs. Backwashing helps to clear any accumulated sediment and regenerate the resin bed, ensuring efficient performance. This step is crucial for maintaining the integrity of the ion-exchange system. Next, brine is introduced to the system. During this phase, the resin is regenerated using a concentrated brine solution, which disrupts the bonds with hardness ions and allows for their removal, effectively recharging the resin. Finally, the rinse phase takes place after brining. This step flushes any residual brine out of the system and ensures that the water flowing out of the system is free from excess salts, preparing the plant for the next service cycle. This sequence is essential for the effective functioning of an ion-exchange softening plant, as each step builds upon the previous one to maintain optimal operation and ensure high-quality soft water output.