Foam Filtration
Currently, an AguaClara plant can produce effluent water after sedimentation with a turbidity of about 5 NTU. Our goal is to reduce the effluent turbidity to less than 1 NTU. One potential method of accomplishing this is adding a filtration unit to the AguaClara plants.
Numerous techniques of water filtration are in use today, most of which involve the use of sand as the porous media. A preliminary  literature review revealed a dearth of information on foam filtration. Our team has decided to focus on investigating the actual filtering capacity of a polyurethane foam material as opposed to the traditional method of sand filtration. With proper implementation, a foam filter could reduce the amount of water that is wasted during the backwash cycle of a traditional sand filter. A foam filter could also potentially require less area, and be less expensive to build than a traditional sand filter. However, a foam filtration unit will also require a tight seal with all of the edges of the tank, in order to avoid preferential flow paths which will result in unfiltered water. In addition, a foam filter will likely require manual maintenance by the plant operator.
With these advantages and cautions in mind, we have considered a number of different designs which could provide the desired standard of 1 NTU effluent water turbidity.
Keep updated with Reflection Reports and Future Challenges
For more information on filtration, visit the General Filtration Page.
Team Members - Fall 2010
Foam Filtration Current Research
Fall 2010
Since laboratory research has shown that horizontal flow foam filtration is not a feasible method for achieving the desired filtration performance, it is necessary to manipulate the geometry of the proposed foam filtration unit in another way. With a high velocity foam filter, the depth of the foam will be increased to accommodate the increased velocity. With an increased filtration velocity, the filtration unit will require less planned area, which reduces the associated construction and maintenance costs.
We would like to analyze the impact of the variation of parameters within our foam filtration experiment in order to determine the optimal set of parameters to design a filtration unit for, and the range conditions which the filter will be effective for. The parameters we will study are filter depth, filtration downflow velocity, influent turbidity, and presence the of an alum dose.
Foam Filtration Past Research
Foam Filtration Future Research
After laboratory tests on the filtering capacity of the polyurethane foam material are concluded, we will continue to explore different research areas. This will include determining head loss across the foam over the run time of the filter, the effect of layering different porosities of foam, the effectiveness of an aluminum hydroxide wash to decrease the ripening time of the foam, and the effects of natural organic matter on the foam material