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Spring 2013 Contributions
This semester, I am working worked on the Sedimentation Tank Hydraulics Team with preliminary objectives to switch to using PAC and optimize the sedimentation tank geometry to positively influence tank performance. We wish to discover . We made a lot of great progress during the semester that included (1) changing the bottom geometry of the sedimentation tank, (2) switching to using PACl and finding the optimum dosage (5 mg/L), (3) exploring the relationship between energy dissipation rate in the jet diffuser and floc blanket performance, and (4) learning about the influence of floc hopper depth on sludge consolidation, how jet nozzle size influences energy dissipation rate (and subsequently, influences the floc blanket), and develop a relationship giving the time until floc blanket formation. Thus far, we have modified the tank geometry to be used for future experiments. We also ran a dye test to better understand the flow of water and colloids through the floc blanket (videos of this dye test can be found on the AguaClara YouTube channel). We found that even at high energy dissipation rates (130 mW/kg), there was improvement in performance over blankets created with lower energy dissipation rates. In addition, we discovered that compression settling occurs in the floc hopper, contrary to our hypothesis that only zone settling was occurring. The dye test showed that while there is evidence showing a slightly preferential flow path through the blanket, the blanket does become uniform and models a PFR as fluid moves through the upper portions. It was a semester filled with lots of hard work and late nights in the lab, but the significance of our findings made it worth all the while.