Floating Flocs Fall 2009 Tentative Experiments

Experiment 1 with Plate Settler's Team: Supersaturated Water with No Bubbles

The objective of this experiment is to test whether supersaturated water by itself without bubbles will cause floating floc. This experiment will test whether bubbles will form on flocs and lift them to the surface.

In order to run this experiment, the pressurized aerator will be used to supersaturate water before it is sent through a bubble trap and through the Plate Settler's apparatus. The bubble trap used must be effective at removing small bubbles in the water. Currently, the Floating Flocs team's flow accumulator is being used to collect small bubbles before they reach the sand filter; however, the design of the flow accumulator does not seem effective at trapping these bubbles since water is drawn from the top of the accumulator. The plan is to move the effluent port of the accumulator to draw water from the side rather than the top to allow for small bubbles to rise to the surface. Another consideration would be to include a longer tube with headspace connecting the system. This would ensure the long enough residence time for the small bubbles to come out more easily.

After a suitable design has been developed for the bubble trap, supersaturated water without bubbles can be sent through the Plate Settler's apparatus where it will be mixed with clay, dosed with alum, and flocculated. In order to observe whether supersaturation of the influent water into the system results in floating floc, the floc blanket in the Plate Settler's apparatus will be monitored to see whether flocs are floating to the surface and whether bubbles are being formed in the process.

Experiment 2 with Plate Settler's Team: Bubbles in Water Saturated with Gas

This objective of this experiment is to test whether bubbles in water that is not supersaturated will result in floating floc.

For this experiment, it is likely that water will be aerated at atmospheric pressure until the dissolved gas concentration equilibrates with atmospheric pressure. The water must then be drawn in such a way that small bubbles will also be drawn into the influent water to the Plate Settler's team. The bubble trap used in the first experiment will be removed to allow bubbles to be sent through the Plate Settler's apparatus. Like in the first experiment, the water will be mixed with clay, dosed with alum, and flocculated. In order to observe whether bubbles in water that is not supersaturated will result in floating flocs, the floc blanket in the Plate Settler's Apparatus will again be monitored to see whether floating flocs are observed.