When should backwashing rate procedures be reassessed?

Reassessing backwashing rate procedures is crucial to maintain the efficiency and effectiveness of granular activated carbon (GAC) filters in water treatment processes. The correct choice emphasizes that significant GAC loss, specifically exceeding 2 inches (or 50mm) per year, warrants a review of backwashing practices.

This threshold is significant because it indicates potential issues such as inadequate backwashing rates or frequencies that could compromise the filter's ability to effectively adsorb contaminants. A loss of GAC can lead to a decline in the quality of treated water, as the filter may not perform optimally if the media is not replenished or the backwashing techniques are not sufficient to mitigate loss.

Monitoring the GAC loss helps in optimizing operational parameters, ensuring that the treatment system continues to function efficiently. By focusing on a specific measurable loss, operators can implement timely interventions and adjustments to enhance system performance and prolong the lifespan of the filter media.