Foam Filtration

Overview

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.

Foam filtration has been ruled out for an AguaClara plant because the foam would be too difficult for an operator to clean. However, previous research has proven that foam is an effective method of filtration, therefore this team will focus on designing a point of use foam filtration unit. Research will be done to optimize the design such that it is as efficient as possible and provides the desired standard of 1 NTU effluent water turbidity.

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 the effectiveness of an aluminum hydroxide wash to decrease the ripening time of the foam, the effects of natural organic matter on the foam material and the most efficient way to clean the foam material.
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