How does a desalination plant work?

Answer 1

Desalination starts out like any other water treatment plant- the water is filtered and treated to get rid of particles, debris, unwanted chemicals, etc.

In desalination, this water is then forced through membranes which have holes big enough to let water through but too small for the salt particles.

Desalination has traditionally been too expensive for most municipalities to use, but as water becomes more scarce, it has become increasingly popular.

See the link below under "Related Links" for a website describing a desalination plant in Tampa Bay, Florida.

Recently seawater desalination process is focused on developing cost-effective ways to provide fresh water for human consumption in areas where the availability of fresh water is becoming more limited.

Seawater is forced through a semi-permeable membrane, which removes all of the dissolved solids and produces fresh, potable water on the other side. The desalination process will reject about 98 percent of salts, contaminates and pollutants from seawater. Salt or brackish water first enters in the RO via a through-hull fitting and is then filtered through the sea strainer. The feed water is boosted to 30 psi by the booster pump and filtered through 25 and 5 micron pre-filters. If oil is present, it is then separated and removed by the oil/water separator. These filters remove sediments and suspended solids from the feed water before entering the high-pressure pump.

The High Pressure Pump supplies the required force to drive the feed water through the semi-permeable Reverse Osmosis (R.O.) Membrane. An automatic high pressure safety relief valve protects the water maker if pressure exceeds recommended levels.

The fresh water produced flows out of the Reverse Osmosis Membrane where it is up to 99.2% free of salts, minerals, and other ions. It then passes into the Product Flow Meter where the amount of potable water produced per minute is registered. Next, the Salinity Probe registers the salt content of the product water. If the water is good quality, it passes through the 1 Micron Carbon Block Post-Filter and ½ Micron Ceramik Post-Filter, which purifies the water of unpleasant odors and taste. Finally, the last filtration process is completed by an optional Ultraviolet Sterilizer where 99.8% of all micro-organisms, including viruses and bacteria are destroyed.