4. (a) When considering aeration of chemostats, describe the different steps that contribute to the overall oxygen trans
Posted: Sat May 21, 2022 3:46 pm
- 4 A When Considering Aeration Of Chemostats Describe The Different Steps That Contribute To The Overall Oxygen Trans 1 (116.78 KiB) Viewed 16 times
4. (a) When considering aeration of chemostats, describe the different steps that contribute to the overall oxygen transfer process. In each case, identify the parameters and / or factors that determine the transfer rate for that step. [8 marks] (b) A simple dynamic test was carried out to determine the oxygen mass transfer characteristics of a chemostat. Once the chemostat was at steady state, the air flow was switched off for a known amount of time, and then restarted. The dissolved oxygen concentration after restarting the air flow is given in Table Q4-1 below. Table Q4-1 Dissolved O2 concentration upon restarting air flow Time [min] Dissolved O2 Concentration [g m-31 1 1.50 3 3.62 5 5.47 7 6.34 9 6.77 11 7.33 13 7.66 15 7.70 8.00 00 1 Given that: Toverall = k_ a' (Coz - Co) rx YX X/O2 where roverall is in g m-3 min-?, determine the value of kla'. g [8 marks] (c) When working at laboratory scale, the oxygen transfer within a Miniature Stirred Bioreactor is said to be better than that within a standard Erlenmeyer flask. Why is this the case? [4 marks]