Desalination Of Salted Water

As every body knows that the raw water sources of the earth may be the sea water, water collected after raining, river streams and glaciers, but this water is not so pure and clean, that it can be used directly for drinking or industrial purposes. As there are several suspended particles in this water, like salt particles, mineral particles, impurities, and some of the metal particles too. So prior to use, this raw water is needed to be cleaned by any of the treatment processes. There are so many brine water treatment processes, which are in use today, out of them distillation, electro dialysis, reverse osmosis and nano-filtration are the most used treatment procedures.

If only the distillation of salt water is considered, then this is the most commonly used process all along the world, from lower level to the highest one. This distillation is basically the thermal desalination process, i.e. the heat (therm) is provided to the water to get the clean and pure water. There are generally three methods of the distillation of salt water.

First one is multi stage flash distillation, or MSF. In this process, the water is heated in Brine heater, and this heated water enters in other container, named as stage, which is at a lower temperature then the previous one. Due to which, the water starts vaporizing, these vapors will be collected and the clean water is obtained.

The second one is Multi effect distillation, which is approximately as similar as MSF. It also works with number of containers each having the temperature lower then the previous one. Each container of multi effect distillation is called as effect, and each effect is made up with a container and a heat exchanger.

The third and the last treatment distillation of salt water technique is vapor compression distillation. In this process, the heat is generated by a steam jet or mechanical compressor.

The thermal desalination process has higher operating costs then other techniques, but lower capital costs. As reverse osmosis and nano filtration, both works with membranes, and these membranes are definitely the expensive as well as sensitive parts of equipment.