Sewage is being treated in two aerated lagoons in series. each lagoon has a surface area of 5 hectares (ha) and depth of 1 m, and each operates as a cstr at steadystate. the influent to the first lagoon contains 100 mg/l of biodegradable organic material in a flow of 8640 m3/d. at steady-state, the effluent from the second lagoon must contain no more than 20 mg/l of the organics. what first-order biodegradation rate constant must be reached to achieve the treatment goal?

Amass of 1.5 kg of air at 120 kpa and 24°c is contained in a gas-tight, frictionless piston-cylinder device. the air is now compressed to a final pressure of 720 kpa. during the process, heat is transferred from the air such that the temperature inside the cylinder remains constant. calculate the boundary work input during this process.

Burgers vector is generally parallel to the dislocation line. a)-true b)-false

A2-m rigid tank initially contains saturated water vapor at 100 kpa. the tank is connected to a supply line through a valve. steam is flowing in the supply line at 600 kpa and 300 c. the valve is opened, and steam is allowed to enter the tank until the pressure in the tank reaches the line pressure, at which point the valve is closed. a thermometer placed in the tank indicates that the temperature at the final state is 200°c. determine (a) the mass of steam that has entered the tank (b) the amount of heat transfer.