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This experiment explored the impact of influent water saturated with air on floc blanket formation and effluent turbidity. This experiment involved collaboration with the Floating Floc Research Team, who supplied the saturated water that served as the influent water to the process.
Abstract Introduction
Our team ran an experiment to investigate the affects of saturated air on floc blanket formation. To do this, our team paired with the Floating Floc research team, who supplied water saturated with air to the process. This experiment is meant to model the effects of having a pressurized supersaturated system and the affects that change in pressure could have on floc blanket formation sedimentation performance due to gas escaping from the influent water as bubbles.
The idea for this experiment is derived from the need to model the affects of altitude change on an actual AguaClara treatment plant. Elevation changes can cause pressure changes in pipe, and as pressure increases, the concentration of dissolved gas water can hold increases. It is suspected that At higher pressures, there is more dissolved gas in the water water can have higher concentrations of dissolved gas. When the pressure is normalized to atmospheric pressure, these dissolved gasses can come out of solution in the form of air bubbles.
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The hypothesis that absorbed air would be released in the apparatus was qualitatively observed by bubble formation. The adverse effects of bubble formation on floc blanket formation and effluent turbidity were supported qualitatively by the appearance of floc particles in cloudiness of the liquid exiting the sedimentation tank effluent (How so? Were there more of them?) . It is possible that these air bubbles caused some of the flocs to break up. In addition, it is likely that these air bubbles disrupted the velocity flow fields in gradient in the tube settler, which is assumed to be a convex velocity gradient whose peak is closest to the tube settler . (What exactly do you mean by disrupting the velocity field? I'm a little unclear by the specifics.)escape. This gradient controls the velocity of the sedement that enters the tube settler, based on a force balance.
Quantitatively, data collected over twenty four hours showed an increase in effluent turbidity when comparing the experiment run with saturated air to the control experiment. (Show the graphs.) We ran this experiment on both high and low floc blanket levels. In the high floc blanket formation state the floc blanket level is above the plate settlers. In the low floc blanket formation the floc blanket formation level is below the plate settlers. The presence of air bubbles could break up some floc particles and force floc particles up into the clarified effluent. Floc particles attached to air bubbles could potentially travel through the tube settler when they would normally settle out.
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It was expected that these bubbles would disturb floc blanket formation, permitting more floc particles to leave with the sedimentation column effluent. An increase in effluent turbidity and the appearance of bubbles in the apparatus supported this hypothesis. If AguaClara is considering to build design a plant which would traverse altitude drops and climbs, results from this experiment should be considered. (AguaClara doesn't "build" plants. AguaClara designs plants.)
Future experiments relating to saturated water in the plant could include bubble removal before floc blanket formation. However, the true effects of saturated air on the experiment cannot be fully determined until the chemical drop waterfall effect is controlled. When chemicals are dropped into the system, such as alum, they create surface bubbles that disturb the system. It is not well understood whether �if- bubbles created from the hydraulic jump in the chemical dose controller falling jets are the potential cause of worsened performance in plate settler effluent or if worsened performance is caused more by the presence of supersaturated air in some plants.