Micro Filtration uses membranes with pore size 0.1-10 µm. Micro Filtration membranes remove all bacteria. Only part of the viral contamination is caught up in the process. This is because viruses can attach themselves to bacterial bio Film (group of microorganisms in which cells stick to each other on a surface ). Micro filtration can be implemented in many different water treatment processes when particles with a diameter greater than 0.1 mm need to be removed from a liquid.