The dissolved oxygen concentration of the liquid was initially stable at 93 % Sat. At t = 0 hr, the oxygen flow was stopped and nitrogen flow was started at a rate of 16 sccm. After about 5 hours, the flow of nitrogen was stopped, the timer was reset, and aeration resumed at a rate of 16 sccm. The oxygen uptake rate of the system is: OUR = 0

What is the DO concentration of liquid that is in equilibrium with the gas being introduced, C* [% sat]?

What is the final steady-state value of the DO concentration, C_L,SS?

What is the volumetric mass transfer coefficient under these conditions?

De-oxygenation DO Time [hr] [% sat] 0 93.1 0.25 72.1 0.5 58 0.75 46 1 30.1 1.25 19 1.5 12.1 1.75 7.5 2 4.9 2.25 3.4 2.5 2.4 2.75 1.9 3 1.4 3.25 1.2 3.5 1 3.75 0.9 4 0.8 4.25 0.7 4.5 0.6 4.75 0.6 Re-oxygenation DO Time [hr] [% sat] 0 0.6 0.25 6.2 0.5 32 0.75 52.8 1 68.3 1.25 78.1 1.5 83.8 1.75 86.9 2 89.2 2.25 90.4 2.5 91.1 2.75 91.6 3 92.1 3.25 92.2 3.5 92.3 3.75 92.3 4 92.3 De-oxygenation DO Time [hr] [% sat] 0 93.1 0.25 72.1 0.5 58 0.75 46 1 30.1 1.25 19 1.5 12.1 1.75 7.5 2 4.9 2.25 3.4 2.5 2.4 2.75 1.9 3 1.4 3.25 1.2 3.5 1 3.75 0.9 4 0.8 4.25 0.7 4.5 0.6 4.75 0.6 Re-oxygenation DO Time [hr] [% sat] 0 0.6 0.25 6.2 0.5 32 0.75 52.8 1 68.3 1.25 78.1 1.5 83.8 1.75 86.9 2 89.2 2.25 90.4 2.5 91.1 2.75 91.6 3 92.1 3.25 92.2 3.5 92.3 3.75 92.3 4 92.3