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The AguaClara team is revising a design for smaller flow rates (under 50 L/s). This page will document and describe the current changes in the Rapid Mix system. The rapid mixer system sizing algorithm is presented is here. Currently, we are now developing an algorithm to plot We are working toward including AutoCAD images for the entrance tank and rapid mixer onto an AutoCAD drawingin our designs.
The suspended particles in the water are removed through a process known as sedimentation. The rate effectiveness of sedimentation is increased by increasing the diameter of the particles through sticking them together. This is done in a with larger particles. A process known as flocculation . Alum is the coagulant of choice used to cause the particles to undergo flocculation. This has to be done rapidly as to ensure the aluminum sulfate does not precipitate before it can be used by the particles. We also need even distribution of alum to the molecular levelstick the particles together, and this results in the creation of larger particles that are easily settleable. A coagulant or chemical that can help stick the particles together is needed. The coagulant used in AguaClara plants is alum. To ensure the effectiveness of alum in flocculating the particles together, we need to have the alum distributed evenly to the molecular level. This is done through the rapid mixer.
The rapid mix system is designed to accomplish this. The rapid mix design consists of piping leading from the entrance tank to the flocculator entrance. The piping contains two orifices. One orifice is for macro-mixing and the other orifice is for micro-mixing. The orifices decrease the cross sectional area of the flow allowing for a higher velocity and thus turbulence. Turbulence, measured in energy dissipation rate, is associated with the formation of eddies which mix the alum to the length scale at which viscosity overrides the formation of eddies with a larger energy dissipation rate being associated with a smaller eddies. The length scale at which the eddies can mix the alum to is known as the Kolmogorov length scale.
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