With more inhabitants on this planet daily, we are being forced to re-evaluate how we use our fresh water. It is a necessary part of our daily lives, from drinking, washing hands, showering, cooking, and so much more. But there’s going to come a point, accelerated by climate change at this rate, where we won’t be able to sustain society with the fresh water we have. So scientists have been working to create more advanced water desalination plants across the world. Desalination is the process of removing sodium from any substance, in this situation I am talking about salt water. In areas that don’t have a lot of fresh water and are situated near an ocean, desalination is a realistic way for them to sustain their needs without having to take water from elsewhere. But it’s not easy to remove salt from large quantities of water, especially at the rate entire countries need o keep up their use. So I wanted to look into how this technology is evolving, and just how far it can take us.
Science of Desalination
The process of desalination has become somewhat streamlined in modern times as a result of much research into the process. The current methods involves pumping salt water from the ocean (or any other non-fresh body of water), and doing one of two things with them. The first is that you can heat up the water to a boiling point, where you will be left with a tank of pure salt. You then have to capture that water vapor and chill it back down in a separate tank to get fresh water. There are a few major issues with this method, in that you need a large amount of electricity to boil that much water, it takes a lot of space to have so many different holding chambers, and it’s nearly impossible to capture back all of the water that you have just boiled. This is the method that is used in the Middle East most often because it is quicker to do then the other one, and they don’t have an issue with creating energy because of their abundance of oil.
The other method that can be used to desalinate water is Reverse Osmosis. This process is considerably more complicated then simply heating the water up. Once you get the water into the plant, you have to use chemicals to make sure you have the right pH balance, pump it to the filtration area, use membranes to filter out the salt (which is around 99% effective at removing salt), and then gets minerals and chemicals added back to make it suitable for consumption. This method does however take considerably less energy, and is somewhat self sustainable. Recently built plants have started using the flow of water as a way to self power themselves, thus cutting down on the environmental impact from energy. However, they do use more chemicals which if not properly regulated could end up back in the water stream These plants tend to be more expensive, but are popular in Europe where there are tighter environmental restrictions.
Downsides to Desalination
While it does provide us an incredible outlet to get nearly unlimited drinking water, there are some concerns with desalination. The first is that it causes significant harm to the environment. Sabine Lattemann wrote a paper entailing some of the biggest environmental threats posed by desalination, among which were harming natural habitats by draining their water, chemical refuse from the plants, and the massive energy use. The one that I find most poignant is the chemical refuse argument, because in the process of making the water safe for consumption these plants are using a lot of chemicals, many of which end up getting dumped back into the ocean. It is also alarming how much energy needs to be used to fuel the plants that heat the water to desalinate, because they are not currently using renewable forms of energy like many reverse osmosis plants are. One final argument is that the companies/governments that run these plants would have complete control over the drining water for an area and that is too much power for them to have. I think with a proper set of checks and balances this could be controlled, but it is something to keep in mind.
I came into this post not knowing much more then what the concept of desalination was, and I came out conflicted. It provides areas that don’t have access to fresh water a way to get it, and that means that society can exist in more places. However, it does pose a threat to the environment if not properly controlled. These plants dumping chemicals into oceans and lakes will only kill off natural wildlife, and the massive energy use to create the fresh water will only contribute to the growing threat of global warming. Also, it is disconcerting knowing that access to water will become a more politicized issue, but I think that’s unavoidable either way. I believe that these plants provide a great opportunity for civilization to thrive, but at the same time we should look into making them more environmentally conscience and sustainable.