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Procedure to Evaluate the Efficiency of Flocculants for the Removal of Dispersed Particles from Plant Extracts
Published on: April 9, 2016
Flocculation model and collision potential for reactors with flows characterized by high Peclet numbers
Monroe L Weber-Shirk1, Leonard W Lion
1Cornell University, School of Civil and Environmental Engineering, Ithaca, NY 14853-3501, USA. mw24@cornell.edu
Water Research
|July 8, 2010
Summary
A new model predicts flocculation time in sustainable water treatment, using energy dissipation rate and hydraulic residence time for better performance prediction than traditional methods.
Area of Science:
- Environmental Engineering
- Water Treatment Technologies
- Fluid Dynamics
Background:
- Sustainable water treatment emphasizes energy efficiency and cost-effectiveness.
- Gravity-driven hydraulic flocculators without mechanical agitation are crucial for these systems.
- Understanding flocculation dynamics under high Peclet number flow regimes is essential.
Purpose of the Study:
- To develop a mechanistically-based model for flocculation characterization.
- To predict the required reaction time for forming settleable flocs.
- To evaluate flocculator performance using novel parameters.
Main Methods:
- Incorporated fractal floc description and floc separation distance estimations.
- Modeled relative velocities of floc particles based on flow regimes.
- Utilized influent turbidity, alum dose, and energy dissipation rate as inputs.
Main Results:
- Viscosity is significant in early flocculation stages; turbulent eddies are significant in final stages.
- A novel 'collision potential' (ɛ(1/3)θ) better predicts flocculator performance.
- This parameter surpasses the conventional velocity gradient (Gθ) predictor.
Conclusions:
- The developed model accurately characterizes flocculation in high Peclet number flows.
- The collision potential offers a superior metric for flocculator performance assessment.
- This approach enhances the design and efficiency of sustainable water treatment systems.
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