Foam Filtration Future Research
Aluminum Hydroxide Wash
Research has shown that the foam material has a fairly long ripening time. In order to reduce this ripening time, it may be useful to prime the filter with an aluminum hydroxide rinse after cleaning. This may reduce the time delay in the filter becoming coated with enough alum to achieve the desired filtration performance. In this test, we will need to determine whether the aluminum hydroxide will result in excess aluminum being washed into the effluent water from the filter. It will then be necessary to determine a washing and foam reinstallation method to reduce this effect.
Effect of Natural Organic Matter
If we conclude from laboratory tests that the foam material provides adequate filtration, it will be necessary to test the effects of natural organic matter on the foam material.
Cleaning Method
After determining the effects of natural organic matter on the foam material, we will propose a standardized method for cleaning and replacing the foam.
Foam Media Upflow Design
Long-term Goals
The largest challenges that remain to be dealt with are:
Determining the toxicity of the foam leaching
Developing a set of governing equations to guide the foam filter design
For forward filter:
Determining effect of stratification and various foam pore sizes on cleaning efficiency
Determining constraints for filter approach velocities
Develop an equation that may predict filter clogging time/ pressure in filter after time T given water influent NTU, PACl dose, filter geometry, flow rate, etc.
For backwash:
Find relationship between force and pore water velocity for various foam pore sizes
Develop relationship between pore water velocity and percent of foam cleaned
Find out how many backwash cycles various foams can take before tearing/breaking/failing
.An alternative to using the foam simply as a flat sheet which water is filtered through is to design a hybrid upflow filter, which uses small pieces of the foam as the filtering material, as opposed to the traditional upflow sand filter. This idea is based on the technique outlined in this article, Water Filtration- Advantages of Fabric Media