*** This version of Confluence is for testing only and contains a copy of content from June 29th 2026. No changes will be preserved. ***
...
Previous research has found that smaller grain sizes are more effective in gas removal than are larger grains in the same volume of sand, since small grains provide more surface area per unit volume on which bubbles can form. Other parameters, such as optimal bed depth and bed expansion, will be determined experimentally. Additionally, since dissolved gas content fluctuates in natural bodies of water, such as the sources of water for AguaClara plants, the dissolved air content of the influent water into the experimental system will be varied to explore its effects on gas removal. The purpose of this team is to test a variety of parameters (listed below) to design an effective sand filter that can be implemented in AguaClara plants.
Parameters
...
Size of sand grain
...
Research performed last semester focused on studying the effects of sand grain size on gas removal. We found that smaller sand grains provide more surface area per unit volume than larger grains, but grains that are too small are carried to the surface with bubbles and are washed away. Grain size also affects porosity of the sand bed, which affects the distance a gas molecule must diffuse to reach a surface. This also may affect aggregation of gas molecules to form larger bubbles. Further study of optimum grain size will be explored through MathCAD modeling, or through experimentation, if that is deemed necessary.
...
Bed depth (i.e., height of sand column before expansion occurs)
...
A range of depths will be explored to determine the relationship between bed depth and gas removal. Experiments have shown that increasing bed depth increases gas removal. Future experiments will explore the exact relationship to determine whether gas removal levels off at some bed depth, etc.
Bed expansion (which depends on the flow rate of influent water)—The expansion of the sand bed affects its porosity, which affects the distance a gas molecule must diffuse to reach a surface, and also may affect aggregation of gas molecules to form larger bubbles. We would like to see the effects on gas removal using different expansions while holding other parameters constant.
...
Dissolved air concentration
...
We would like to determine whether effectiveness of gas removed depends on the concentration of dissolved gases in the influent water. We plan to adjust the amount of supersaturation, probably by varying pressure in the aerator to decrease the dissolved oxygen concentration.
...