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Figure 1. Experimental apparatus
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h4. Tube Flocculator
h5. Introduction
Water turbidityBasically, the flocculation process is causedthe bytransformation colloidalof particlesa in suspension (andof theparticles presenceinto oflarge naturalflocs organicthat mattercan andbe otherremoved organic and inorganic contaminants)by sedimentation. TheseTo colloidalimprove particlesthe areperformance too small to settleof flocculators, andwe dueneed to theirresearch negativelyhow charged surfaces, they electrostatically repel each other. Flocculation transforms these repelling colloidal particles to attract and form into flocs that are large enough to settle out in the sedimentation tank. The probability (collision potential) that particles collide in a flocculator depends on the the design and operational parameters that affect the aggregation and setting velocity of the flocs. These parameters include energy dissipation rate, andhydraulic residence time, incoagulant thedose, flocculator. As flocs collide, they grow in size making it easier to remove them in subsequent processes. influent turbidity, etc. 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 velocity. Therefore,Our 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 goalapparatus (flocculation residual turbidity analyzer or FReTA) is capable of measuring both settling velocity and residual turbidity under different flocculator operating conditions.
The goals of the Tube Floc Team isare to determine the parameters (such as optimal energy dissipation rate, hydraulic residence time, etc.) that will produceinfluent quicklyturbidity settlingremoval flocsand thatto candevelop removeflocculation themodels greatestas percentagea ofguideline the turbidity for a variety of influent water qualities and provide better guidelines in designing a flocculation systemdesign.
If you are new to the team or would like to know more about the upkeep of our experimental setup, check out the [basics|Basics on Tube Floc]. An excellent resource for information on the FReTA setup is Ian Tse's M.S. thesis: [Fluid shear influences on hydraulic flocculation systems characterized using a newly developed method for quantitative analysis of flocculation performance|^Ian Tse MS Thesis.doc]. This thesis contains detailed information on the [Process Controller] states, rules, and set points as well as descriptions of the data analysis process.
h5. Current Research
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{color:#000000}{_}Chemical Dosage Jar Test{_}{color} !Jar test.jpg|align=right,thumbnail!
{color:#000000}We use the jar test to find the optimal dosage of PACl and Na2CO3, which controls the chemical stock concentration when running the tube flocculator apparatus. The Na2CO3 is used to control the pH of the water because we need to maintain the pH at 7.5 throughout each experiment.{color}
{color:#000000}{_}Ion Effect on Flocculation{_}{color}
{color:#000000}The current research showed a tap water with high ionic strength could perform quite well in flocculation, while the distill water with very low ionic strength could hardly form flocculator. We use the simulated tap water (by adding different known chemicals) to figure out which group of ion plays the key role in a good flocculation.{color}
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h5. Challenges for Future Semesters
* Currently, we have figured out ionic strength and hardness could affect the flocculation performance, but we cannot tell which group of ions really work, and/or how they influenced the performance_Right now this team is working on breaking large flocs at regular intervals in the flocculator to see how the floc breakup affects the performance of flocculator._
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h5. Challenges for Future Semesters
* To test tapered flocculation which is realized by reducing the energy dissipation rate gradually so that the flocs are able to grow.
* To research how the presence of suspend and dissolved organic matter influences dose.
* Special Skills Needed:
** CEE 4540: This course could provide a fundamental understanding about municipal drinking water treatment.
** MathCAD: We use this software to do the calculation for the research.
** Lyx: This software is helpful when writing a scientific report.
h5. More Information
[Fall 2011 Research|https://confluence.cornell.edu/display/AGUACLARA/Fall+2011+Research]
[Fall 2010 Research|https://confluence.cornell.edu/display/AGUACLARA/Fall+2010+Tube+Floc+Research]
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h6. Members
[Ruijia Li|rl564]
[Xuexiang Zhang|xz248]
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h6. Documents
| | Challenges | Tasks | Teach-In | Presentation | Final Report |
| Fall '12 | [!Research^pdf_icon.jpg|height=25!|^FlocculationChallengesFall12.pdf] | | | | |
| Fall '11 | [!Research^pdf_icon.jpg|height=25!|^TubeFlocculator.pdf] | [!Research^pdf_icon.jpg|height=25!|^Tube_Flocculator-Detailed_Task_List.pdf] | [!Research^ppt_icon.jpg|height=25!|^Tube Flocculator.pptx] | [!Research^ppt_icon.jpg|height=25!|^Final Presentation - Tube Flocculator.ppt] | [!Research^pdf_icon.jpg|height=25!|^Tube Floc- Final Report.pdf] |
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h6. Past Research
[Sophie Bernat|smb397]
[Young-Jin Chung|yc487]
[Alexander O'Connell|amo47]
[Dali Sun|ds679]
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