In conventional filtration technology, the entire liquid stream is pumped through the filter medium. This is known as "dead-end" filtration.

Membrane filtration usually uses a "cross-flow" or "tangential flow" scheme. This technique allows continuous processing of liquid streams, because the bulk solution flows parallel to the filter surface. Pump pressure forces the liquid through the filter. The turbulent flow of the bulk solution over the surface minimizes the accumulation of particulate matter on the filter, and facilitates continuous operation of the system.

Here are some illustrations of the two processes