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- Attempt to recreate the foam in a laboratory setting that has been forming in many of the AguaClara plants in Hoduras.
- Design a way to retrofit the current plants to eliminate the foam
- Learn about the current design for a Nonlinear Chemical Dose Controller and then update MathCAD code for the controller and hopefully be able to build a fully functional prototype by the end of the summer.
These two goals (which two?) are very important to the overall goals of AguaClara for a number of reasons. The foam that forms in the current AguaClara plants both increases the amount of work that plant operators have to spend to keep the water clean, and reduces the overall effectiveness of the plants. Although the foam cannot flow very far in the plant itself, it can be blown around by wind to the surface of the sedimentation tank. Small bubbles formed by decreased surface tension in rapid mix could persist as far as the sedimentation tank, where they would come out, possibly causing the floating floc problem. We suspect that the surfactants and natural organic matter lower the surface tension energy requirements, possibly creating these small bubbles that stay in solution long enough to reach the sedimentation tank.
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Also, as we evolve to build larger plants, the Linear Chemical Dose Controller (LCDC) won't be able to provide a sufficient dose of chemicals to treat the larger flow rates. The CDC team from past semesters has found that the LCDC can only provide chemical flows up to 400mL/min, which is too low for larger plants. Linear dose control depends on a change in head in the plant inflow tank to move a float up and down, which changes the flow of alum into the water. Thus, a Nonlinear Chemical Dose Controller (NCDC), where flow will not vary linearly with water height like the LCDC, is needed for bigger plants. A discussion of the need for a NCDC can be found in the second paragraph on the NCDC page. This summer we will need to improve upon the initial design of a NCDC in order to make it more dependable and robust.
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Retrofitting Plants to Prevent Aeration Experiments
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