Design a flotation unit considering: temperature of 30C and therefore an air solubility (sa) of 15.7mL/L, an optimum A/S ratio of 0.01mL air /mL solids, a fraction of air dissolved (f) equal to 0.5 , a concentration of solids (S) equal to 2,800mg/L, inflow rate equal to 500m3/d, and a rise velocity of the solid-bubbles of 30L/(m2min). Calculate for the design: 1) The pressure (P,atm) to apply in the pressurized tank to dissolve air into the influent; and 2) the surface area of the flotation basin