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Objective and Motivations
The goal turbidity of any flocculation process is to transform suspended colloidal particles into flocs that can be removed by sedimentation. The design of sedimentation tanks is dictated by the settling velocity of the flocswater is caused by colloidal particles in suspension (and the presence of natural organic matter and other organic and inorganic contaminants). Colloidal particles are too small to settle and due to their negatively charged surfaces, electrostatically repel each other. Flocculation transforms colloidal particles into larger flocs that can settle out in the sedimentation tank. The probability (collision potential) that particles collide in a flocculator depends on energy dissipation rate and residence time in the flocculator. As flocs collide, they grow in size making it easier to remove them in subsequent processes. One of the goals for the AguaClara team is to develop a sedimentation tank that will form a fluidized floc blanket, which will help clean water as it flows into the sedimentation tank from the flocculator. To develop this floc blanket the flocculator must produce flocs that fall within a particular range of settling velocities. Therefore, it is important to research the parameters that affect flocculation and the resulting floc size distribution.
Conventional design guidelines for a hydraulic flocculator are incomplete and the dynamics of how physical parameters affect flocculation are not well understood. The goal of the Tube Floc Team is to try to Our goal is to determine the parameters (such as optimal energy dissipation rate, hydraulic residence time, etc.) that will produce fast settling flocs that can remove the greatest percentage of the turbidity in the waterfor a variety of influent water qualities and provide better guidelines in designing a flocculation system.
The apparatus
Experimental apparatus
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