How does the application of air scouring during filter backwashing specifically improve the removal of trapped solids compared to water backwashing alone?

Air scouring during filter backwashing improves the removal of trapped solids compared to water backwashing alone by more effectively disrupting and loosening the filter bed and breaking up compacted solids. Water backwashing alone relies on the upward flow of water to expand the filter bed and carry away the accumulated solids. However, water alone may not be sufficient to dislodge tightly packed solids, especially those that have become cemented together or attached to the filter media. Air scouring involves injecting compressed air into the filter bed before or during the water backwash. The air bubbles vigorously agitate the media, creating intense shear forces that break up clumps of solids and detach them from the filter media. This agitation is far more effective at disrupting the filter bed than water backwashing alone. The air scouring action helps to break up mudballs, which are clumps of solids that can form in the filter bed and reduce its efficiency. It also improves the removal of biofilms that may have formed on the filter media. By more effectively loosening and removing trapped solids, air scouring helps to restore the filter bed to its original clean state, leading to improved filter performance, longer filter run times, and reduced headloss. Air scouring also often reduces the volume of water required for backwashing, making the process more efficient. An example would be a filter that experiences mudball formation despite regular water backwashing. Introducing air scouring to the backwash cycle can break up these mudballs and significantly improve filter performance.