The facility must treat 12,000 kg/min water. The density of the salt water is 1060 kg/m3. Filter beds of coarse sand media are available as units with an 11 meters depth and another 0.7 meters depth for backwashing. The packed bed porosity is 0.42 and the shape factor of the sand is 7.5. Average grain size is 1.3 mm with a density of 2.6 g/cm^3. The maximum superficial velocity through the beds is 1.2 m/min.

1) Filters can be purchased as pre-built units with cross sectional areas of 2.5m^2. Specify how many filters are needed if for every 5 filters on-line, one is being regenerated (hints: to solve this problem, you will need a loading rate value. Research filter beds, and select one that fits what you need for this design. Use its loading rate and the given mass flow rate to calculate the total filter area needed for this plant. Then divide the total area needed by the given unit area to find the number of beds needed)