During back washing of a mixed media filter, what is the expected bed expansion percentage?

During backwashing of a mixed media filter, bed expansion is a critical process that helps to remove trapped solids and regenerate the filter media. The expected bed expansion percentage typically falls within the range of 10% for most mixed media filters.

This percentage is crucial because it indicates how much the media bed swells during backwashing due to the upward flow of water. A 10% expansion is generally sufficient to facilitate the dislodging of dirt and debris while still maintaining the structural integrity of the media. If the bed expands too much or too little, it could lead to inefficiencies in the filtration process or potential damage to the filter system.

Understanding this expected bed expansion is essential for proper operational parameters and effective maintenance of the mixed media filter, ensuring optimal performance and longevity of the equipment. This is why the 10% figure is considered the benchmark in this context.