Common Questions About Water Desalination
What is desalination?
Desalination is the removal of salts from seawater, brackish and other saline waters. Reverse Osmosis (RO) achieves this by pushing water through a membrane that acts as a sieve of sorts. Larger components like salt and bacteria are too large to pass through the membrane, while the smaller water molecules pass through. The process effectively separates water from the larger contaminants resulting in potable drinking water.
Desalination of seawater and brackish groundwater has been used effectively in many parts of the world for more than 100 years. It is the primary source for potable water for many countries including Israel, Saudi Arabia, UAE, Australia and quite a few others.
What is brackish water?
Brackish water is defined as water containing a total dissolved solids (TDS) concentration of more than 1000 milligrams per liter (mg/L). In contrast, seawater contains about 35,000 mg/L of dissolved solids, e.g. salts and minerals.
Studies indicate that there are significant reservoirs of brackish groundwater throughout the southwest United States. In many cases the reserves of brackish water below the surface dwarfs the surface water volume that many have come to depend on. An additional benefit of these groundwater reservoirs is that they do not evaporate during our prolonged summer heat.
How much does it cost?
The cost to process brackish water is roughly half the cost of processing more saturated sources like seawater, yet it is processed with the same technology. Generally stated, the cost to desalinate brackish water runs between $2-4 per 1000 gallons.
Is it practical for the southwest?
Desalination offers a viable, drought-proof solution to water needs in the Southwest United States. Several billion acre feet* of brackish water lie beneath our land. As our needs continue to grow, brackish desalination, along with conservation and reuse must become part of our communities’ water portfolio.
* 1 acre foot (af) equals 326,000 gallons