108
Sl. No.
Membrane
Pore size (nm)
Pictorial representation of substance filtered
1
Micro- filtration
0.05–2
Water
molecules
Monovalent
ions
MulƟvalent
ions
Small
Organic
molecule
Virus
Suspended
solids larger
than pore size
Bacteria
Viruses
Large
Organic
molecule
2
Ultra- filtration
0.005–0.1
Water
molecules
Monovalent
ions
MulƟvalent
ions
Small
Organic
molecule
Virus
Suspended
solids larger
than pore size
Bacteria
Viruses
Large
Organic
molecule
3
Nano-filtration
0.001–0.05
Water
molecules
Monovalent
ions
MulƟvalent
ions
Small
Organic
molecule
Virus
Suspended
solids larger
than pore size
Bacteria
Viruses
Large
Organic
molecule
4
Reverse osmosis
0.0005–0.02
Water
molecules
Monovalent
ions
MulƟvalent
ions
Small
Organic
molecule
Virus
Suspended
solids larger
than pore size
Bacteria
Viruses
Large
Organic
molecule
Table 5.1 Pore size in membrane filtration
5 Water and Wastewater Treatment