h1. Plate Settler Spacing

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h5. Introduction

This research is focused on a deeper understanding of the sedimentation process so that plants can remove dirt particles from dirty water as efficiently as possible, allowing for successful chlorination of the outgoing water. Currently the plants all use lamella, which are corrugated parallel plates that decrease the distance that a floc must fall to be settled out. To make things simpler for a lab, we use tube settlers of various diameters, and experiment with different flow rates and turbidities, because these things fluctuate often in the plants in Honduras based on the season.

One of the main reasons for this focus is that sedimentation is the only process in which particulates are actually removed from the water. Flocculation and rapid mix may be working well, but if the particles are not being settled out, people will still be drinking dirty water. Low turbidity water is not only aesthetically pleasing, it's also safer because the disease causing pathogens are more likely to be exposed and killed when the water is chlorinated. AguaClara has had the goal of 1 NTU water since its beginning, and the Plate Settler Spacing team has been able to accomplish this in the lab, but now is trying to see how this can be transferred to our future plants in Honduras. Sedimentation is also the limiting factor for the height requirement of the plants, so if we can find a way to produce the same results with a smaller amount of space, the plant cost will decrease significantly.

[Subteam Semester Goals and Future Challenges|Plate Settler Spacing Goals]
[Weekly Subteam Progress|Plate Settler Spacing Meeting Minutes].

h2. Experimental Methods and Results


h3. Spring 2009


h5. [Experiments with Flow Rates and Inner Tube Diameters|PSS Tube Settler Experiments]

This section contains two related experiments. The first experiment varies flow rates and the inner diameter of the tube settler. From these results, the ideal L/d ratio is identified and held constant for a certain flow rate and inner diameter by varying the tube length.

h5. [Floc Blanket Formation|PSS Floc Blanket Formation]

Experiments exploring the rate of formation and density of floc blankets.

h3. Fall 2008 Preliminary Testing


h5. [Fall 2008 | Plate Settler Spacing Research Fall 2008]

This section contains preliminary observations and data that preceded the experiments run during spring 2009, above.

h3. Summer 2008 Preliminary Testing


h5. [Experiment Using Straws for Tube Settlers|Plate Settler Spacing Research Summer 2008]

These early experiments explored the impact of the diameter of tube settlers on effluent turbidity. Tube settlers were modeled using drinking straws.

h2. Additional Information

[Annotated Bibliography of Relevant Literature|PSS Bibliograhpy]

[Processor Controller Information|PSS Process Controller and Data Analysis]

[PSS Quiz for New Members |PSS Quiz]

[Fall 2008 Photo Gallery|Photo Gallery]

[PSS Apparatus Design]