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MathCad Results: Empirical vs. Simple Hydraulics (Conservative) Approach

1) Our design based on simple hydraulics will work. However, it is a very large filter *\[ how large\]*  and will not be sustainable economically. The material cost for construction will be too high.
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2) The design based on the empirical Weber equation (instead of the conservative approach) is smaller and less expensive *\[ how small\]*. However, the validity of the empirical equations is not yet certain. Therefore testing needs to be done in bench and pilot scale models.
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3) If the empirical equations are valid, then we can change parts of the design, by changing the sand parameters. For example, lower BW velocity by lowering the d60 and specific weight of the media.

Experiment Results

We had mixed results with regards to Weber's equation for filter bed expansion. At low levels of filter bed expansion, the Weber equation accurately predicted the fluidization velocity required to achieve the targeted bed expansion. As the target bed expansion increased, so did the degree of error. At 9% expansion, the degree of error was at 14%. At 38% expansion, the degree of error was at 37%.

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