1.A fan produces a pressurerise of 6mm of water to move air through a hair dryer. The mean velocity of the air at the exit is 10 m/s, and the exit diameter is 44 mm. Estimate the electrical power in watts that needs to be supplied to operate the fan. Assume that the fan/motor combination has an efficiency of 60%.
2.A small town produces 0.15 MGD of wastewater. How many acres in size would an aerated lagoon need to be to treat this wastewater assuming a depth of 8 ft. and a detention time of 6 days? (7.48 gal/ft^3 ; 43,560 ft^2/acre)