Sewage Filtration And Water Treatment

Reverse osmosis is an efficient technique for dewatering, concentrating or separating low-molecular-weight substances in wastewater. It can be used to concentrate all dissolved and suspended solid materials. The most important usage for reverse osmosis is desalination of seawater.

Osmosis is a physical process in which a solvent moves, without need of external energy, across a semi-permeable (allowing fluids or gases to pass or diffuse through) membrane (a thin sheet of natural or synthetic material), separating two solutions of different concentrations as the denser solution stays on the surface while the less dense goes through it. In reverse osmosis the solvent is forced through the membrane by applying pressure. This way even smaller particles such as salt ions can be separated because the use of pressure enables the use of membranes with more dense structure that wouldn’t let water pass through it using regular osmosis.

Nano-filtration is selected when Reverse Osmosis or ultrafiltration are not suitable. For example, nanofiltration can be used for demineralization.