Membrane Processing is a separation technique widely used in food, dairy, chemical,
and water treatment industries. It uses a semi-permeable membrane to separate components
based on size, pressure, or concentration differences—without changing phase (no evaporation
required).
Basic Principle
A membrane allows certain substances (like water or small molecules) to pass through while
retaining others (like fats, proteins, or bacteria).
The driving force is usually pressure difference across the membrane.
Types of Membrane Processes
1. Microfiltration (MF)
Pore size: 0.1–10 µm
Removes: Bacteria, fat globules, suspended solids
Used in: Milk clarification, bacteria removal
2. Ultrafiltration (UF)
Pore size: 0.01–0.1 µm
Removes: Proteins, enzymes, macromolecules
Used in: Concentration of milk proteins, whey processing
3. Nanofiltration (NF)
Pore size: 0.01 - 0.001 µm
Removes: Small organic molecules, some salts
Used in: Partial desalination, lactose concentration
4. Reverse Osmosis (RO)
Pore size: Very fine (molecular level) 0.0001 – 0.001 µm
Removes: Dissolved salts, sugars, water purification
Used in: Water removal from milk, wastewater treatment
Components of Membrane System
Feed tank – contains liquid to be processed
Pump – provides pressure
Membrane module – where separation occurs
Permeate – filtered liquid passing through membrane
Retentate – concentrated material left behind
and water treatment industries. It uses a semi-permeable membrane to separate components
based on size, pressure, or concentration differences—without changing phase (no evaporation
required).
Basic Principle
A membrane allows certain substances (like water or small molecules) to pass through while
retaining others (like fats, proteins, or bacteria).
The driving force is usually pressure difference across the membrane.
Types of Membrane Processes
1. Microfiltration (MF)
Pore size: 0.1–10 µm
Removes: Bacteria, fat globules, suspended solids
Used in: Milk clarification, bacteria removal
2. Ultrafiltration (UF)
Pore size: 0.01–0.1 µm
Removes: Proteins, enzymes, macromolecules
Used in: Concentration of milk proteins, whey processing
3. Nanofiltration (NF)
Pore size: 0.01 - 0.001 µm
Removes: Small organic molecules, some salts
Used in: Partial desalination, lactose concentration
4. Reverse Osmosis (RO)
Pore size: Very fine (molecular level) 0.0001 – 0.001 µm
Removes: Dissolved salts, sugars, water purification
Used in: Water removal from milk, wastewater treatment
Components of Membrane System
Feed tank – contains liquid to be processed
Pump – provides pressure
Membrane module – where separation occurs
Permeate – filtered liquid passing through membrane
Retentate – concentrated material left behind
