6) (15 points) For a flow rate of 0.8 m³/s, how many rapid sand filters are needed to accommodate a loading rate of 110 m/d-m²? Each filter bed has a

surface area of 10 m x 10 m. How should this design be adjusted to accommodate the need to backwash filters(just comment on needed adjustments, you do not need to provide an adjusted number of filters)?