Question

Question 1

You are assigned to carry out a preliminary design for a water treatment process. A pollutant of concern, denoted ‘A’, is known to degrade in water. But you do not know the rate law or reaction rate constant. You conduct a series of experiments. In each case, you established an initial concentration of 50 mg/L of pollutant ‘A’ in water in a sealed vessel. After a certain period, you open the vessel and measure the remaining concentration of ‘A’. The results of your experiment are tabulated below:

Experiment                  Duration of Experiment                                    Final Concentration (mg/L)

           

1                                  1 hour                                                  35

2                                  3 hours                                                 17

3                                  6 hours                                                 6

a) What is the rate constant?

b) You are to design a reactor to treat a constant flow rate of 0.3 m³/s of water containing 50 mg/L of ‘A’. If the reactor is configured as a complete mixed flow system, how large must it be to achieve 90% removal of ‘A’.

c) Size a plug-flow reactor in place of complete mixed flow reactor for the similar situation mentioned in (b).

d) If you would like to propose two complete mix reactors of equal volume in series what should be the volume of each reactor.

Answer 1