Importance And Advances Of Desalination

Planet Earth, a vast, mystical wonderland located inside the Milky Way Galaxy, is not your traditional habitat, housing over eight million species of life forms and innumerable land/sea infrastructure. Our world, as we know it, is advancing in ways we cannot imagine, not only in habitual ways, but in means of technology and science. Today, man has advanced so much to the point that we have begun to take losses and self-inflicted wounds upon ourselves. For example, there was a time, just a few years ago, where a cameraman and pilot were needed in order to capture that cinematic shot for a movie. Today, technology has grown so much that both the cameraman and pilot have lost their jobs to AI technology due to the creation of drone footage. For this footage, all you need is a single person with knowledge of photography and drone flying. Although many advancements have been made, with claims to benefit earth and the environment, not all have been a detriment to society. Of those advances, we shift our focus onto the process of desalination and how it has become such a key concept in our lives today, even if we do not know it.

For much of society, we fail to realize the longevity of our world and how we are mere “guests,” here only for a few years. Our earth has been around for over four billion years and today is over two thirds covered by water, seventy one percent to be exact, and twenty nine percent land. Water is an extremely key component and necessity to maintain life and homeostasis on earth. With this in mind, how can we use some of this water to our advantage while, of course, creating minimal collateral damage? The answer to this question is the concept of desalination. Desalination is the process of removing salt and other impurities from water (seawater, fresh water, waste, etc.). With the reduction in recent years/decades of fresh water, due to daily maximal use, desalination is critical for ensuring there is a sufficient supply for humans to use and to, in general, preserve the safety of the future for humanity.

In 1791, Thomas Jefferson and Jacob Isaacks invented the earliest forms of desalination where they describe the simplest form of desalination, distillation, by means of heat (endothermic reaction) resulting in water vapors and fresh water. This process involved the idea of simply boiling water and was then printed and given to traveling vessels so that they could drink fresh water in case of an emergency. Today. the most common way of desalination (distilled-based) is also thermally driven, which include methods known as Multistage Flash Distillation (MFD), Multiple-Effect Distillation (MED), and Mechanical Vapor Compression (MVC) processes. In the Multistage Flash Distillation process, seawater is heated in a heat exchanger known as a brine heater. This is done by condensing steam on the surfaces of pipes passing through the heat exchanger, which leads to the heating of seawater in these pipes, creating distilled fresh water. On the other hand, the Multiple-Effect Distillation method is an evaporation method where sea water is evaporated in one or more evaporation stages (up to 14 stages) at low temperature (less than seventy degrees Celsius) in order to produce clean distilled water. The MED process goes hand in hand with the mechanical vapor compression method because when no steam is available, scientists use the MED process and add a Mechanical Vapor Compressor, which adds energy to low-pressure vapor in means of compression, resulting in a smaller volume of vapor at a high temperature and pressure. In such case, the vapor is recycled from the cold cell to a hot one by using a centrifugal compressor driven by an electric engine.

Although thermal desalination is a very effective form of generating fresh water, it has its defects. Of those deficiencies, the main concern is the amount of energy being consumed. Energy is a key ingredient when deriving fresh water through a thermal process and scientists believe too much energy is being used to work this process. As a result, we are slowly moving from thermal driven desalination to membrane driven desalination. Membrane desalination has many alternative forms, including reverse osmosis, nanofiltration and many more. Reverse osmosis (RO) uses a permeable membrane that allows the removal of ions, unwanted molecules and larger particles from water. Nanofiltration (NF) is not far off from reverse osmosis, with the difference merely being Nano filters remove organic compounds from water, such as pesticides and heavy metals. Another form of membrane based distillation is Electrodialysis (ED) which is when ions flow through selective membranes to electrodes of the opposite charge. In Electrodialysis Reversal (EDR), the polarity of the electrodes is reversed periodically, resulting in the transfer of the ion’s anion and cation membranes to separate the ions in the water. The last form of membrane based desalination is Forward Osmosis. Forward Osmosis (FO) is a relatively new desalting process in which a salt concentration gradient (osmotic pressure) is the driving force through a permeable membrane. Seawater is on one side of the membrane and a higher osmotic pressure draw solution is on the other. Without applying any external pressure, seawater will naturally make its way through the membrane to the draw solution. The diluted solution is then processed to separate the product from the reusable draw solution. All in all, membrane based desalination is an effort to reduce the amount of energy consumption and generate more fresh water. Today, it is an ongoing process and scientists are still working day and night to create a more cost effective as well as ecofriendly way to provide fresh water.

We, as humans, have seen a lot of growth in the world around us, whether it was financially, economically, scientifically, or technologically. If we look at the bigger picture, we can indeed conclude that science and technology both are the most important in civilization today. For generations and generations, our forefathers have made an attempt to understand the world around us and to learn to cope with it, while trying to advance and maintain the homeostasis of our environment. Understanding the criterion of desalination may seem like a walk around the park but it is indeed a very important concept to grasp. It is very important to stop and thinking about the water that you are drinking on a daily basis, whether it is tap water, bottled water, or even sparkling water. Have you ever wondered how it is made and provided to us without any trouble? That is how important desalination is in modern society. By converting seawater, spring water, waste water etc., we are able to meet our daily nutrient requirements and thus, stay alive. The science and technology that is involved to develop processes as stated above are unique and it is imperative to continue to expand this research and griw upon it. Only then will humanity stay, strive and prosper.