How Reverse Osmosis Works

Disadvantages of Reverse Osmosis

So now we've seen some of the ways we can harness reverse osmosis to work for us. But does asking nature to reverse itself necessarily a good idea? There are a few issues that arise from using reverse osmosis, and we'll start with checking out what happens in desalination reverse osmosis.

After the water is filtered, you're left with lovely drinking water. But on the other hand, you have a whole mess of salt left to deal with. What do you do with the brine, which usually contains twice the amount of salt as seawater [source: The Economist]? Is it a problem to dump that brine back in the ocean? According to the Australian Centre for Water research, salinity seems to return to normal around 500 meters (about 1,600 feet) from the source [source: The Economist]. However, no one has yet gotten clear answers about if the metals and chemicals also trapped in the brine can cause an environmental impact.

Reverse osmosis systems, in general, are also not entirely self-sustaining. Water must be pretreated with chemicals, for instance, so nothing will clog the fine membrane. And the membrane itself is not entirely easy to deal with; it must be cleaned often, and can trap bacteria. A concern unique to the desalination plants is that small fish or marine life can be sucked into the system; adjusting intake pressures and velocities can usually prevent harm.

The biggest impediment of reverse osmosis filtration systems is the cost. For a developing nation, installing reverse osmosis systems is a fairly impractical possibility. Organizations like the WHO and UNICEF consider building reverse osmosis water treatment plans -- to remove toxins or provide a clean water supply -- part of their mission.

As for individual use, reverse osmosis systems can produce frustratingly little yield. A typical system will only be able to reuse about 5 to 15 percent of the water that's being pumped in, thus leaving up to 85 percent wastewater [source: NDSU].

Reverse osmosis -- and the ways it works and doesn't work -- can be a bit daunting. But if you're thirsty for more reverse osmosis information, go to the next page where you can find a lot more information.

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