Asmall treatment plant with two filters operates at a filtration rate of 2 gpm/ft2 . the influent tss is 15 mg/l; the effluent tss is 0. (a) if each filter is square, 30 ft on a side, calculate the daily volume of water treated (in million gallons/d, mgd) assuming each filter is backwashed once per day in a process that takes 30 minutes. (b) if 3% of the treated flow is used for backwashing, calculate the backwash tss. (answers: 5.08 mgd, 500 mg/l)

Aloaded platform of total mass 500 kg is supported by a dashpot and by a set of springs of effective stiffness 72 kn/m. it is observed that when the platform is depressed through a distance x = 12.5 cm below its equilibrium position and then released without any initial velocity; it reaches its equilibrium position in the shortest possible time without overshoot. find the position and velocity of the loaded platform 0.10 sec. after its release. if a further load of 400 kg is added to the platform, find, i) the frequency of damped vibrations, and i) the amplitude of vibration after 2 complete oscillations, given that the initial amplitude is 15 cm.

Water at 70°f and streams enter the mixing chamber at the same mass flow rate, determine the temperature and the quality of the exiting stream. 0 psia is heated in a chamber by mixing it with saturated water vapor at 20 psia. if both streams enters the mixing chamber at the same mass flow rate, determine the temperature and the quality of the existing system.

Aplate clutch has a single pair of mating friction surfaces 250-mm od by 175-mm id. the mean value of the coefficient of friction is 0.30, and the actuating force is 4 kn. a) find the maximum pressure and the torque capacity using the uniform-wear model. b) find the maximum pressure and the torque capacity using the uniform-pressure model.