Particles, scaling and biofouling
Particle membrane pollution can be defined as suspended and colloidal matter, which absorbs to the membrane. Solids will plug the membrane, causing that the water that needs treatment is no longer able to pass through. When the membrane is plugged, more pressure is necessary to be able to perform the usual water treatment. This causes energy costs to rise.
Scaling means the deposition of particles on a membrane, causing it to plug. It is an unwanted effect that can occur during nano filtration and Reverse Osmosis processes. Scaling causes a higher energy use and a shorter life span of the membranes, because these will need cleaning more often.
Biological contamination, known as biofouling, occurs most often during nano filtration and Reverse Osmosis processes. This is because the membranes cannot be disinfected with chlorine, in order to kill bacteria. Biofouling in nano filtration or Reverse Osmosis membranes is probably the least comprehended contamination that can occur in membrane systems. This can be ascribed to the complex growth of microbiological bacteria. These microrganisms have damaging, often irreversible effects on nano filtration and Reverse Osmosis systems.
One of the most abundant types of biofouling originates during pre-treatment of Reverse Osmosis systems and in parts of membrane systems that can promote the growth of algae. Membrane system parts that are exposed to sunlight or contain still water can cause the growth of algae to expand.