Membrane filtration has developed into a cost effective technique to filter our impurities from wastewater. There are different kinds of membranes that are employed to remove different kinds of contaminants. 

The membranes are distinguished from one another based on a number of factors, such as:

1. Their membrane pore sizes; can be classified into micro, nano and ultra filtration membranes. 
2. The type of material they are made of. 
3. Their orientation; sheets or tubes, horizontal or vertical placement.