同海大学 Tongji University Head loss in filter increases with time as filter clogs and Ripening gets low hydraulic conductivity Breakthrough Good Removal At end of filter run,filter is "back washed". Strong flow sent back through porous medium, mobilizing grains,and washing solids off of Clean Bed medium Filter Run TimeTongji University • Head loss in filter increases with time as filter clogs and gets low hydraulic conductivity • At end of filter run, filter is “back washed”. • Strong flow sent back through porous medium, mobilizing grains, and washing solids off of medium