Depth filtration means that the filtration takes part in the depth of the filtermedium.
In most case the dirt holding capacity of the depth filter is higher than of the surface filter.
A disadvantage of depth filtration is the broad cut-off; this means that a 100micron depth filter also remove particles of 50 micron.
In some case this broad cut-off can be a problem because good elements in the solution are also removed.
Depth filtration can take place in a filterbag, filtercartridge, filterplate or an precoat filter such as a DrM Fundabac.
The choise between depth filtration or surface filtration is a very importact decission.