Backwashing in a rapid-sand filtration system reverses flow to clean the media. Which cues indicate backwashing is needed?

• A. Rising headloss, rising effluent turbidity, and decreased filter performance.
• B. Decreasing headloss and improving effluent clarity.
• C. Stable headloss with no change in performance.
• D. Decreased flow rate with enhanced filtration.

Answer: (A)