If newly installed manganese greensand is not skimmed of fines after backwashing, what is the immediate consequence?

• A. Increased filter efficiency
• B. Longer filter runs
• C. Shorter filter runs
• D. Better water quality

Answer: (C)

When newly installed manganese greensand is not properly skimmed of fines after backwashing, the most immediate consequence is a reduction in filter efficiency, leading to shorter filter runs. This occurs because the fines, which are small particles of the greensand media, can clog the filter bed. Such clogging reduces the overall flow rate through the filter, making it harder for water to pass through effectively.

The presence of these fines can also create pathways for water to flow through the filter without being adequately treated, diminishing the treatment process's effectiveness. Consequently, a filter that is not cleared of fines may require more frequent backwashing, resulting in shorter operational periods between cleaning cycles. Thus, while the goal is to maintain high-quality water treatment, neglecting to skim off fines disrupts this process and leads to inefficiencies.