What is Reverse Osmosis?
The osmotic process involves the natural movement of a solution through a semi-permeable membrane without applying external pressure. The membrane allows the passage of solvent but not of solute. In Reverse Osmosis, high pressure is used to push the solution through a membrane, which traps the solute on one side making pure solvent obtainable from the other side.

How does it work?
In the case of marine water purification, sea water is driven under high pressure through a special membrane. The resulting “Product Water” is potable water with over 99% of the Total Dissolved Solids (TDS) removed. The Product Water is directed from the watermaker to an appropriate location such as a fresh water holding tank. Permeate that does not successfully pass through the membrane is sometimes referred to as the “brine discharge”, and is also directed to an appropriate place. For example, on vessels, the brine discharge is diverted overboard.

A marine desalination system begins with a through-hull fitting, or skin fitting, where ocean water is initially drawn into the system. The raw sea water is then filtered through a sea strainer to approximately 50 microns; and, further filtered to 5 microns by being pumped through a Pre-Filter using a Low Pressure Pump running at approximately 30–35 psi. Now, the Reverse Osmosis process begins. The filtered sea water is then pumped under high pressure (at approximately 800–850 psi depending upon the temperature and salinity of the sea water), through the system’s membrane vessels. The Product Water that successfully passes through the membranes is then routed to a salinity probe, which confirms the quality of the water produced. If the Product Water is acceptable, this purified water is transported to a fresh water holding tank. Unacceptable Product Water, which does not pass the salinity test, is discarded and diverted with the brine discharge.

FCI's exclusive Universal Reverse Osmosis Controller, UROC, technology allows you to monitor water production and control your water purification system from a computer and remote locations. FCI Watermakers are among the most effective desalination systems providing automatic and customisable fresh water flushing. This feature is integral to every marine water purification system because it deters growth of biological contaminants when the system is not in use.

Additional marine water maker accessories include a UV steriliser, which kills over 99% of all micro-organisms in the water, and a charcoal filter, which neutralises water odours and taste.