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h1. Demo Plant Spring 2008 Sedimentation Tank Design
h2. Design Goal
Our goal this semester was to redesign the sedimentation tank to be open to the atmosphere on the top, eliminating the need for a weir to control the plant water levels. Also, this would make it easier to fill and clean for demonstrations. We also explored various methods for creating equal flow rates in neighboring lamellas in the sedimentation tank.
h2. Theoretical Design
h3. Principle Formulae
h3. MathcadMathCAD Files
h3. Algorithm
h3. Design Results
h4. {toggle-cloak:id=Open Top Design}Open Top Design
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This design will be very similar to the Summer 2007 design, with the exception that the top of the sedimentation tank will be open to the atmosphere. Due to this adjustment, the weir will no longer be necessary for plant water level control. Also, the sedimentation tank will now need to be almost as tall as the flocculator, to prevent overflowing. The water levels in the flocculator and sedimentation tank will be approximately the same.
According to the MathCAD Files, this design will need 13 lamella to maintain the proper upflow velocity.
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h4. {toggle-cloak:id=Perpendicular Open Top Design}Perpendicular Open Top Design
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TheThis new sedimentation tank design proposed in Spring 2008 will address the problem of uneven flow lengths, rates, and shears through each lamella of the sedimentation tank in the Spring 2007 Demo Plant. This problem is further described in the [Demo Plant Problems Encountered] page.
The proposed sedimentation tank will be oriented perpendicular to the axis of the flocculator. -Additionally, to accommodate the new design, water will exit the flocculator from the top, instead of the bottom.- In order to eliminate differences in lengths of flow paths through the sedimentation tank, water exiting the flocculator will be split into several tubes of equal diameters and lengths, which will enter the bottom of the sedimentation tank. The tubes entering the sedimentation tank will be evenly spaced.
The sedimentation tank itself will be redesigned so that lamella still form the optimal 60 degree angle. However, the lamella will now guide the water in a path parallel to the axis of the flocculator, so that the whole tank will have an incline, and will need to be either very bottom-heavy, or have a support for the upper ends of the lamella. This design, along with the new entry method, will normalize the head loss through individual channels in the sedimentation tank.
The proposed sedimentation tank will also incorporate an open-top design, similar to the flocculator of the Fall 2007 Demo Plant.
This design also allows us to consider the incorporation of a drain for built up sediments in the sedimentation tank, adding the functionality to clean the sedimentation tank while the plant is still running.
*The* *[*MathCAD design*|^Demo Plant Sedimentation Tank.xmcd]* *and* *[*AutoCAD drawing*|^Demo Plant Sedimentation Tank.pdf]* *of the proposed sedimentation tank have been uploaded.*
!Demo Plant Pictures and Figures^Demo Plant Sedimentation Tank AutoCAD.jpg|thumbnail!
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h4. {toggle-cloak:id=Open Top Parallel Lamella Design}Open Top Parallel Lamella Design
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h4. {toggle-cloak:id=Open Top Parallel Lamella Design}Open Top Parallel Lamella Design
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blobThis design is very similar to the first Open Top Design, but it will take into account the varied flow rates observed throughout the lamellas of the sedimentation tank. Instead of one row of lamellas, we will have two parallel sets of lamellas. Each set will have 7 lamellas, resulting in a total of 14 lamellas on the entire sedimentation tank.
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h2. Construction
h3. Materials
h3. Description of Construction Process
h3. Pictures of Finished Product
h2. Post-Construction Modifications
h3. What didn't work
h3. How it was remedied | 