3) (35 pts) There is a dual-media filter with 0.5 m of anthracite coal and 0.3...
3) (35 pts) There is a dual-media filter with 0.5 m of anthracite coal and 0.3 of sand. Other data for anthracite: specific gravity is 1.67, porosity is 0.5, deo grain size is 1.5 mm. Other data for sand: specific gravity is 2.65, porosity is 0.4, doo grain size is 0.9 mm. The water temperature is 200, so the mass density of water (p) is 998.2 kg/m' and the absolute viscosity is 1.002 x 103 kg/m-s. Assuming a 30% margin of safety for backwash, calculate the following: a) the recommended backwash rate for the filter (gpm/sf) b) the pressure drop through the filter during fluidization (psi) Note: multiply (L/m²-s) by 1.473 to get gpm/sf. Multiply (N/m?) by 0.000145 to get psi.