High cost and energy intensiveness remain the primary barriers for desalination, the conversion of salt ocean water into fresh water. The prospect of providing more drinking water to areas of need is appealing, but experts usually weigh the pros and cons of desalination when deciding whether it’s a suitable alternative. As such, it’s considered a final resort for providing fresh water.
Ideally, sourcing water from lakes, rivers, streams and other natural water sources is the preferred method for drinking water, but global warming and general pollution have made many former water sources become devoid of water. In addition to growing populations in desert regions, there’s an increasing need for more fresh water, which desalination can provide at a cost.
Negative Impacts on Ocean Life
Desalination contributes to the release of fossil fuels, as the process burns up significantly more fossil fuels as opposed to sourcing from fresh water bodies. Desalination plants leave a hefty carbon footprint. Ocean biodiversity is also negatively impacted by these plants, as their intake pipes have a tendency to vacuum and kill millions of fish larvae, plankton, fish eggs and other organisms in the ocean. Impacts in the food chain have a variety of negative outcomes, so fossil fuels and these plants combine for a gradually devastating effect.
Additionally, salty sludge is the resulting leftover from desalination. As is the case with any type of sludge, it has the ability to severely interrupt marine ecosystems.
Jeffrey Graham of the Scripps Institute of Oceanography’s Center for Marine Biotechnology and Biomedicine states for every one gallon of freshwater produced from desalination, we must dispose of a gallon of doubly concentrated salt water, which likely plays a role in the disappearance of some marine organisms.
Specifically, desalinating water using reverse osmosis contributes to “noise pollution, visual pollution, reduction in recreational fishing and swimming areas, emission of materials into the atmosphere,” and the brine discharge contributing to pollution, according to the National Center for Biotechnology Information. Marine life can be severely affected by the high density of brine discharge, as their impact on the food chain is great despite their size or ocean depth.
When a Last Resort Becomes Logical
While the negative effects of desalination are clear, the potential of people dying or becoming ill due to dehydration is difficult to ignore. As such, some view the risks of losing human life as outweighing the environmental effects.
When you consider that less than 1% of the world’s water supply is fresh, and much of that is being compromised by overutilization, contamination and climatic influences, there’s a pressing need for desalination in some places. At the very least, the cost for desalination is beginning to decrease with the rise of desalination plants, with around 300 of them in the USA.
In addition to lowering costs that should increase research going toward desalination, there are new ways to combat the high energy intensity of desalination, with bio-engineered energy solutions using the process of
forward osmosis to siphon clean water from the intake.
New methods like these are using less than a quarter of the electricity required for standard desalination, which shows potential for the process eventually becoming less disruptive toward the environment. For now though, there are ample concerns regarding the environment, including the high emission of fossil fuels and ecosystem disturbances.
With the process not disappearing anytime soon, the environmentally minded can hope for increased research into more efficient methods that provide the benefits of desalination without the carbon footprint and bio-system interference.