Asewage lagoon that has a surface area of 10 ha and a depth of 1 m is receiving 8640 m3 · d−1 of sewage containing 100 mg · l−1 of biodegradable contaminant. at steady state, the effluent from the lagoon must notexceed20mg·l−1 . no losses or gains of water in the lagoon other than the sewage input, what biodegradation reaction rate coefficient (d−1) must be achieved for a first-order reaction?

Adouble-strand no. 60 roller chain is used to transmit power between a 13-tooth driving sprocket rotating at 300 rev/min and a 52-tooth driven sprocket. a) what is the allowable horsepower of this drive? b) estimate the center-to-center distance if the chain length is 82 pitches. c) estimate the torque and bending force on the driving shaft by the chain if the actual horsepower transmitted is 30 percent less than the corrected (allowable) power.