Desalination Pros and Cons List
Desalination is the process of removing salt from water. At its root, it is a very simple process. Water is boiled off and condensed on another surface, leaving the salt behind in the original container. This is called distillation. Reverse osmosis is another method of desalination which forces water through a very fine filter that prevents the salt from passing through. Desalination has many benefits, but there are downsides to the process that also need to be considered.
List of Pros of Desalination
1. Saltwater Abundance
In many areas of the world, fresh water is in short supply. California is currently in the midst of the most severe drought in recorded history. Salt water, on the other hand, is very plentiful. Desalination turns salt water into fresh water, which is invaluable for people who have no other source of water or whose main source is failing them. This water can then be used for drinking or for agricultural needs.
When most people think about a water shortage, they think about not watering their lawn or washing their car. But to a farmer, water rationing can be devastating. In the world’s arid regions, irrigation is absolutely necessary for growing many of the local crops. Not having these crops to sell has an enormous detrimental effect on the economy. A shortage of fresh, locally grown produce can also impact the diets of residents. All in all, having to forbid farmers from irrigating their crops does not work out well for anyone. Desalination can make that entire chain reaction unnecessary by providing the water that farmers need for their crops.
2. Not Dependent on Changing Factors
One of the greatest problems with many proposed solutions to the growing water demand is that they are dependent on uncontrollable factors. Building more reservoirs presupposes that there is going to be the rain or snowfall needed to fill them. Desalination does not rely on anything other than the presence of the ocean. With the concern surrounding the melting of the polar ice caps and the rise of the ocean levels, nobody is concerned about the ocean disappearing anytime soon.
3. Reliable Technology
Unlike many of the proposed technologies for dealing with emerging problems in the world, distillation and reverse osmosis are not in the research stage. They have been proven and used for years for a variety of applications, including water purification. Neither method is volatile or risky. People who argue for desalination as a way to combat drought conditions strongly emphasize the point that we have the technology at hand to address the problem and that we know how to use it. This is not a pie in the sky dream of what might be possible someday. It is a workable solution.
List of Cons of Desalination
1. Energy Costs
The main problem with desalination is that it takes an enormous amount of energy. Distillation requires heating countless gallons of water to boiling temperature before it can be recollected and used. Reverse osmosis is no better. Osmosis is a natural process. Reversing it is very energy demanding. People who oppose desalination as a workable solution for the drought problem facing various regions of the world argue that the energy costs are simply too high for it to be a long term, sustainable solution.
2. Expense
Desalination plants don’t just use up a lot of energy, they also use up a lot of money. Building the plant creates a very large cost upfront that many of the poorer sections of the world simply can’t afford. There is then the added expense of providing the energy to keep the plant operating. Research in the U.S. has found the desalinated water costs five times as much to harvest as other fresh water sources. This cost is eventually passed on to the consumer, many of whom can’t or won’t pay that much for their water. There is a functional desalination plant in Santa Barbara, California, but that water is specifically held in reserve for emergency use only because the water is simply too expensive for people to buy as long as they have any other option.
3. Waste
The whole point of the desalination process is to remove salt from water. This leaves the producer with large amounts of brine on their hands that have to be disposed of in some way. Chlorine and anti-scaling agents are often added to the water and then left behind in the brine. Dumping this waste back into the ocean plays havoc with the ecology and kills marine life. The other by-product of desalination is carbon emissions. The huge amounts of energy used in the process create an equally large amount of emissions that are released into the atmosphere and damage the ozone layer.
Desalination is a proven and effective way of turning saltwater into freshwater that is usable for drinking, livestock, and irrigation. The technology to do so is fully understood and can be used today, not after years of additional research. Unfortunately, it takes enormous amounts of energy to drive these plants. The price of that energy ends up making desalinated water cost prohibitive. If there were a source of cheap, renewable energy that could be utilized in the process, it would be a much more manageable solution. As it currently stands however, it looks like desalination is going to continue to be held in reserve for emergency purposes only.