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Uneven flow among layers of the stacked filter would be a significant operational problem. The hydraulic design and sand media selection for a stacked filter must account for proper distribution of flow in the filter but there is little data to support design guidelines for either of these. We hypothesize that uneven sand gradation will lead to coarser and finer layers of the filter, and we would like to know how much of a problem this will be and how quickly it may correct itself.
Current Research
"selfSelf-healing" test to look at what happens when we have two layers with unequal sand grain size
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