DO Removal by Partial Vacuum and Aeration

Purpose and Principle

The purpose of this experiment is to observe and quantify the change in dissolved oxygen transfer out of supersaturated water that is subject to slight aeration under a partial vacuum. This experiment attempts to use air bubbles as a catalyst to increase the rate of dissolved oxygen out of the water. The difference in oxygen concentration between the bubbles and the supersaturated water may be used to draw excess dissolved oxygen into the bubbles and out of the solution.

Procedure

The procedure is similar to that of the previous experiment. However, instead of turning off the pump once a partial vacuum is established, the partial vacuum is maintained while the solution is aerated. The flow of air into the container is regulated by a rotameter that takes either lab air or room air. Originally, lab air was being used; however, later experiments involve detaching the air inflow tube into the rotameter and allowing air to be sucked into the apparatus as it would be through the holes in the actual pipes. After the water is aerated under partial vacuum for a period of time, the apparatus is again exposed to atmospheric pressure and data is recorded in the same manner as mentioned before.

Results and Discussion

Conclusion