What term refers to a series of treatment steps that are redundant in their ability to remove contaminants?

• A. Single-barrier approach
• B. Sequential-treatment method
• C. Safety-net strategy
• D. Multiple-barrier approach

Answer: (D)

The term "Multiple-barrier approach" refers to a series of treatment steps that provide redundancy in the ability to remove contaminants from water. This strategy is fundamental in water treatment as it enhances the reliability and safety of the treatment process. Each barrier or treatment step targets specific contaminants, ensuring that if one method is less effective for a certain type of contaminant, subsequent barriers can still effectively reduce that contaminant to acceptable levels.

By incorporating multiple treatment steps, the overall risk of contaminant failure is minimized, and the water quality is maintained at a high standard. This approach is particularly important in water treatment facilities to account for variations in contaminant levels and types, ensuring that the water produced is safe for consumption.

In contrast, the other approaches differ in their emphasis on singular treatment methods or do not focus on the redundancy aspect of the treatment system. For instance, a single-barrier approach relies on a single treatment method, which may not provide adequate protection against all potential contaminants.