The air shed over a city can be considered by a completely stirred tank reactor (CSTR) model with two sides of 2×10° m in length and a mixing depth of 500 m. Horizontal wind blows at 4 m/s from one side of the box and exits from the opposite side. Assume that within the box, the air is well mixed all the time. Within the air shed, benzene (CH6) is emitted by automobiles, power plants, and factories at a rate of 0.4 kg/s. No benzene is brought to the city by wind. When equilibrated, what is the benzene concentration in the atmosphere? Please sketch the model first. Pay attention to the units.

The removal of phenol in an industrial waste stream by microorganisms can be characterized as a first-order reaction. The reaction rate coefficient was measured in a batch system, k = 0.05 min¯¹. The proposed reactor size is constrained by existing process equipment to a square area 20 x 20 m. The effective liquid depth can be no greater than 2 m. For a flowrate of 10 m³/min, what is the most efficient reactor configuration: a single CMF, 4 CMF's in series, or a PF reactor? Support your decision with computations.

A jet of water issues from a 5 cm diameter nozzle, held vertically upwards, at a velocity of 20 m/s. If air resistance consumes 10% of the initial energy of the jet, then it would reach a height above the nozzle of m.

A smokestack emits pollutant Z into the air on a sunny day. The effective stack height is 270 m. The wind speed is 4 m/s, due east. Your house is located 4.0 km due east of the smokestack. The ground level concentration of pollutant A is 2.0 mg/m3at your house. Your friend lives 4.0 km east and 1.5 km south of the smokestack. a. What is the emission rate of the pollutant in kg/s? b. For the emission rate determined in part a, you now want to know the concentration of pollutant Z at ground level at your friend’s house. i. What parameters change in the dispersion modeling equation? For each parameter, include the parameter symbol, a definition of the parameter, and its new quantitative value and required units.ii. Is the concentration at your friend’s house lower, the same or higher than the concentration at your house and why? (you do not need to calculate the concentration) show all work