Freshwater shortage? Saline Groundwater to the Rescue!

By: Melissa Bracero

You may or may not know that there is a global shortage of freshwater, and it is not going to get any better for the next few years (Gleick, 2003). There is a high demand for freshwater supply because of increasing population and needs. This is putting a lot of pressure on both arid and semiarid countries, especially because there has been a decrease in available water resources. All thanks to ground water contamination due to reverse osmosis desalination of seawater (Hoekstra and Mckonnen, 2012). Reverse osmosis (RO) desalination of seawater is one way that we get freshwater supply. This process, though beneficial by giving freshwater, has a lot of drawbacks. A major problem with this method is the fouling that is produced by seawater. The desalination plant takes up a lot of land and consumes a large amount of energy (Stein et al. 2016). Economically speaking, it is to expensive to be constantly conducting this process. In this article, the best possible water to use instead of seawater is saline ground water (SGW). Some of the methods used were: water sampling, fouling experiments and water chemistry analysis. The major disadvantage that seawater desalination has is the fouling it produces, but in their results SGW produced little amounts of fouling.The results also showed that saline ground water used about 15% lower osmotic pressure, which means it requires less energy (Stein et al. 2016). Another advantage to SGW is that its temperature stays constant during the changing season. This means that SGW needs less adjustments than seawater desalination. Overall, SGW is a better choice than desalination of seawater. Environmentally, SGW plants are smaller requiring little land, needs less maintenance, uses low energy, and has a quick recovery (Stein et al. 2016). Economically, it would be less stress on the wallet. 

References

Groundwater from coastal aquifers is a better source for desalination than seawater. (n.d.). Retrieved September 09, 2016, from http://phys.org/news/2016-03-groundwater-coastal-aquifers-source-desalination.html 

Gleick, P. H. Global freshwater resources: soft-path solutions for the 21st century. Science (Washington, DC, U. S.) 2003, 302 (5650), 1524−1528.

Hoekstra, A. Y.; Mekonnen, M. M. The water footprint of humanity. Proc. Natl. Acad. Sci. U. S. A. 2012, 109 (9), 3232−3237.

Stein, S., Russak, A., Sivan, O., Yechieli, Y., Rahav, E., Oren, Y., & Kasher, R. (2016, September 16). Saline Groundwater from Coastal Aquifers As a Source for Desalination. Environmental Science & Technology Environ. Sci. Technol., 50(4), 1955-1963. doi:10.1021/acs.est.5b03634