Backwashing should expand the filter media by what percentage?

Backwashing is a crucial process in maintaining water treatment filters, as it helps to clean the filter media by removing accumulated particles and debris. When backwashing occurs, the filter media should expand to allow for effective cleansing of the surface and prevent compaction of the materials, which can hinder water flow and filtration capacity.

The correct answer indicates that the filter media should expand by 30 to 50 percent during backwashing. This expansion is necessary to ensure that the water can dislodge trapped particles effectively and carry them away. An expansion in this range optimizes the backwashing process, improving the filter's performance and longevity by ensuring that the media is properly cleaned.

An expansion outside this range may not provide the same effectiveness in cleaning. If the expansion is too low, the backwash may not adequately lift and remove the accumulated debris. Conversely, if the expansion exceeds 50 percent, it may risk damaging the media or negatively impacting the filter's integrity. Understanding this optimal range is vital for water operators to maintain the efficiency and reliability of filtration systems.