Abstract: A filter apparatus having multiple filter medias for use in environmental control, food processing and other industrial applications, is provided with movable filter media separators that maintain media separation while permitting bed expansion during a backwash cleaning operation. The filter bed can comprise, for example, a lower sand layer and an upper anthracite layer, as well as a free board zone above the anthracite layer. Said layers are separated by a movable filter media separator. A screen is provided at the filter inlet to prevent loss of filter media during the backwash cleaning operation.