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
.