From Sea to Sink

This article reviews supplies of water under stress; the prospect of rendering saltwater drinkable is growing more appealing and more affordable. A combination of need and cost is making desalination of saltwater more attractive in the United States, and reverse osmosis is the overwhelming choice when it comes to desalination methods. Desalination, the removal of salt from either brackish or seawater to render it potable, is nothing new. Desalination processes are generally divided into two methods: thermal and membrane. Either process can be used for seawater or brackish water. Brackish water is saltier than fresh water, but typically not as salty as seawater. It may result from the mixing of sea and fresh water, as in estuaries, or it may occur naturally, as in underground aquifers. Brackish water concentrate disposal poses more of a problem, largely because those facilities are typically located inland, so there's no nearby ocean to send the brine back into. Instead, these facilities pump the concentrate into deep wells.