Changes

==Types of filtration==

==Types of filtration==

Two common types of filter media used in stormwater treatment are granular media, such as sand, and membranes:   

Two common types of filter media used in stormwater treatment are granular media, such as sand, and membranes:   

'''Granular media''' is a multilayer lattice or matrix that traps solids as water flows through the tortuous channels in the media.  Clogging may occur when solid particles form a film or cake on top of the filter or accumulate within the media channels to the point where the channels become occluded.   

'''Granular media''' is a multilayer lattice or matrix that traps solids as water flows through the tortuous channels in the media.  Clogging may occur when solid particles form a film or cake on top of the filter or accumulate within the media channels to the point where the channels become occluded.   

'''Membranes''' have very thin separation lattices with openings or pores that remove all particles larger than the nominal pore size of the filter at the surface, thereby acting much like a sieve.  Membranes are often pleated to increase the surface area, allowing for more particles to be trapped prior to clogging.

'''Membranes''' have very thin separation lattices with openings or pores that remove all particles larger than the nominal pore size of the filter at the surface, thereby acting much like a sieve.  Membranes are often pleated to increase the surface area, allowing for more particles to be trapped prior to clogging.