Florida Drinking Water Operator "B" Practice Test

What is a major disadvantage of an ion exchange softening plant?

1. High energy consumption

2. Production of hard water

3. Disposal of the spent brine and rinse waters

4. Increased chemical usage

The correct answer is: Disposal of the spent brine and rinse waters

A major disadvantage of an ion exchange softening plant is the disposal of the spent brine and rinse waters. During the ion exchange process used for water softening, sodium ions are exchanged for calcium and magnesium ions that cause hardness. This process generates a byproduct, known as spent brine, which contains a high concentration of various salts and other impurities that were removed from the water. The disposal of this brine poses environmental challenges and regulatory concerns, as it can contaminate local water bodies if not managed properly. Proper disposal methods may involve additional costs and logistical considerations, making this an important disadvantage when assessing the overall impact of an ion exchange softening plant. In contrast, the other options do not accurately reflect the primary drawbacks of using an ion exchange softening system. For instance, high energy consumption and increased chemical usage can vary based on specific operational practices and system designs, while production of hard water contradicts the purpose of the system, which is specifically intended to reduce water hardness.