Salt Water Reverse Osmosis Plants

What Is Salt Water Reverse Osmosis?

• Reverse osmosis is a water-filtration technique that was developed 40 years ago as a simple method to purify water. The basic principle of reverse osmosis uses the natural tendency of water to migrate from a weaker salt solution to a stronger one and reverses it. to move water from the stronger seawater solution to the less-saline solution. Techniques and equipment gradually improved over the years to make it an effective and affordable way of treating water for many communities where salt water is readily available.

How Does Reverse Osmosis Work?

• The basic method, osmosis, uses a semi-permeable membrane to equalize the salt content in two tanks of water, one not salty and the other salt water. Salt is a large molecule that is filtered out easily by this membrane. Mineral molecules are also large and can be filtered out of water. Reverse osmosis uses electricity to pressurize the water and push it through the filter mechanically, leaving the salt and mineral content on one side of the membrane, while clean water is left on the other side.

Reverse Osmosis Desalinization Plants

• Salt water reverse-osmosis plants are in operation in many countries around the world, including the United States, Saudi Arabia, Iraq, India, China, Algeria and Australia, according to the April 2011 San Diego World Trade Center Report by Andreas Fried. In the United States, salt water reverse-osmosis plants are in operation in Florida, California and Texas.

Advantages of Salt Water Reverse Osmosis Plants

• Salt water reverse-osmosis is often the most cost-effective way of treating water for communities along coastlines, depending on the availability of other ground water sources and how far the water may need to be piped to supply the city. The cost is even lower when the plants are in close proximity to power plants that provide the electricity for the process. Salt water reverse osmosis uses a relatively simple technology to remove the salt from water. A variety of different filtering options are available for varying needs. Equipment and technical knowledge to implement it is widely available throughout the world.

Disadvantages of Salt Water Reverse Osmosis Plants

• Salt water reverse-osmosis plants require considerable initial investment. The costs of electricity, membrane replacement and trained personnel can also be prohibitive for small communities. The incoming water may need pre-treatment to remove particles that cause deterioration of the filtering membranes. Also, a significant amount of replacement parts must be retained in inventory to keep plants running continuously, according to the Organization of American States website.