Desalination

Desalination is the process of removing the salt portion of an aqueous solution. In our sector, we refer above all to the removal of salt from seawater in order to make it suitable for human or industrial use.

Today, with the water emergency that is emerging in the world, the desalination of seawater is becoming increasingly important.
The main technology used is reverse osmosis. The typical design of a desalination plant consists of:

• Marine water catchment
• Relaunch of treatment
• Filtration on quartzite
• Microfiltration 20 µ + 5 µ
• Chemical descaling
• High-pressure electric pumps (≃ 60-70 bar) + energy recovery system
• Trains of osmotic membranes specially manufactured for use with seawater

The permeate can be accumulated and made available for other treatments or for relaunching the services, while the concentrate, except in special cases, is generally delivered to the sea.

Over the years, this technology has undergone considerable maturation, managing to achieve increasingly better performance by reducing energy use. The main developments concern the creation of increasingly efficient membranes (equal saline production and rejection with a lower operating pressure) and the efficiency of high pressure systems through the use of inverters and energy recoverers that allow the pressurisation of feed water through an energy transfer from the waste (concentrate).