The wastewater flowrate to the treatment plant is 0.42 m3/s, with a BOD5 concentration of 436 mg/L and suspended solids concentration of 238 mg/L. Design the primary clarifier (find dimensions) for an overflow rate of 42 m/d and detention time of 2 hr. The tanks have a rectangular configuration with a length to width ratio of 5. Assume 8 tanks working in parallel. Assume clarifiers are working well, estimate the 1o effluent BOD5 and SS concentrations.

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.

Abrake has a normal braking torque of 2.8 kip in and heat-dissipating cast-iron surfaces whose mass is 40 lbm. suppose a load is brought to rest in 8.0 s from an initial angular speed of 1600 rev/min using the normal braking torque; estimate the temperature rise of the heat dissipating surfaces.

During a steady flow process, the change of energy with respect to time is zero. a)- true b)- false