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What is Desalination and the various methods used?

Any procedure that removes salts from water is referred to as desalination. Desalination methods can be employed in municipal, industrial, or commercial settings. Desalination technologies are becoming cost-competitive with alternative means of providing useable water for our expanding requirements as technology advances.

By using this procedure, such inedible fluids may now be used for irrigation, industrial uses, human consumption, and a number of other things. With current technology, desalination is a costly process since it takes a lot of energy, typically in the form of fossil fuels. This is why it is often only utilised in situations when there are no viable alternatives for purchasing fresh water supplies. Desalination facilities produce enormous amounts of brine effluent and greenhouse gas emissions, which present serious environmental problems.

 DESALINATION PROCESSES

Distillation, which involves boiling saltwater in a still, collecting steam, and condensing it to create fresh water, is the most obvious method for removing salt, but it is not the most efficient since it requires a lot of energy. The following is an overview of the primary desalination methods currently in use:

·     Reverse osmosis

It is the most often used technique and uses less energy than the others since it is based on the use of semipermeable membranes that allow water but not salt to flow through. These membranes are composed of ultra-thin polyamide, which can become polluted with bacteria, thus the water must be cleaned.

·     Solar distillation

It replicates the water cycle by evaporating saltwater in big facilities with roofs, where it condenses and is recovered as fresh water. Despite the fact that the energy utilised is the heat of the sun, enormous expanses of land are required.

·     Electrodialysis

It works by passing salt water over electrically charged membranes, which trap the salt ions dissolved in the water and allow fresh water to be extracted. There are several types of electrodialysis, including standard and reverse.

·     Nanofiltration

It is a method that employs nanotube membranes that are more permeable than reverse osmosis membranes, allowing more water to be treated in less area and with less energy. These membranes are made of sulfonated chemicals that, in addition to salt, remove residues of contaminants.

·     Gas hydrate formation

Gas hydrates are solid crystals created by mixing high pressure and low temperature water with a gas, such as propane. All of the salts and contaminants in the water are removed throughout the process, and when the temperature rises, the gas may be collected, leaving just fresh water.

Advantages of Desalination

·     Desalination is a recognized technology

Scientists realize that even when done correctly, the desalination process is an efficient means of producing safe, useable water for big populations. Additionally, you may utilise this technology to produce useable emergency water on a personal level in case utility or municipal systems go down for whatever reason. That implies there are large-scale and small-scale answers to practically every demand, whether you want to develop a sustainable water supply at two pints per hour or two gallons per second.

·     During a drought, desalination allows us to get water.

Another major issue that human civilizations encounter each year is drought. Some locations see above-average rainfall while others may have prolonged periods of below-average activity as global weather patterns shift.

Desalination gives us a mechanism for getting water to people who need it the most. Access to water is a need of existence even if it may not always be the best option.

·     We might generate additional energy by using the water flow caused by desalination.

Desalination facilities generate water motions that might be beneficial for turbine spinning when they pump water into their facility to begin the processing activity. We might be able to generate power while also obtaining access to additional freshwater if we installed practical hydropower technology at these inlets. Ideally, certain facilities could very well be able to generate the energy required for saltwater processing through the operations they now carry out. Creating more water resources can also help to lower our global energy expenditures in other ways. 25% of the energy used in the world today is used to supplement the food supply. Agriculture consumes the most freshwater. If we can exploit this advantage more efficiently, we may be able to save more energy for other purposes.

·     Desalination helps to maintain economic stability on all levels.

Water is essential for us to carry out our everyday activities. We can’t operate as efficiently without access to it. We can stabilise economies all throughout the world by creating extra reservoir supplies that are open to the entire population.

We might design freshly anticipated cost structures for customers of local utilities who have more reliable access. We would be able to produce more goods, construct more assets, and keep up current levels of horticulture output. Diversified water resources foster stable regional and global economies.

·     Desalination plants are beneficial to several businesses.

During the desalination process, we remove salt from water that is extremely concentrated and hazardous if left in the environment carelessly. It may also be utilised in a variety of different ways by other businesses. Products containing sodium can be used as dicing agents. Ice may be effectively kept off of transportation networks using aqueous brine solutions.

Desalination’s by-products are helpful in limiting the amount of dust present. They are injected during fracking operations as materials. Even more materials are added to it to create “saltstone,” a product made from concrete.

Disadvantages of Desalination

·     There are important disposal demands for chemical waste to take into account.

After producing fresh water for usage, desalination produces a number of byproducts, each of which must be disposed of in a precise way to protect people and the environment. Pre-treatment and cleaning procedures make the operation more effective than using a straightforward strainer. Most facilities prepare the water for this procedure using hydrogen peroxide, chlorine, and hydrochloric acid. Once the chemicals have been utilised, they must be properly disposed of in order to keep them out of the water table.

·     There is a lot of brine produced during desalination that has to be controlled.

Brine is a byproduct of a desalination process. Once the salt is gone, facilities will ship the purified water for additional processing, but the leftover sodium super-saturation product needs to be disposed of carefully. Many facilities just return it to the ocean, but many marine species are unable to cope with the elevated sodium levels. If too much brine is put into the local supply, too much salt will lower the oxygen levels in the water, which might cause local life to suffocate.

·     Plants for desalination need a lot of energy.

Today, as we work to address some of the problems that climate change is bringing about, energy is a vital resource for us. Some experts believe that before we reach a point of no return, we have until the year 2030 to start making changes to the processes that led us to where we are now. Desalination of water has a number of advantages, but it requires a lot of energy to produce anything that can be used. There are various methods of water purification that use less energy while yet giving us the drinking water we need to survive.

·     Some desalination processes drain the water’s electrolytes.

The fluid must pass across a membrane in order to desalinate water via reverse osmosis. This process cleans the water of pollutants so that it may be used as a product. Additionally, it will eliminate all of the nutrients in the water, including the calcium, magnesium, and potassium that are essential for a healthy lifestyle. Industrial facilities often reintroduce these components into the supply before distributing the fluid for consumption, but this drawback raises the price of the final product even further.

The major desalination plants in the planet

  • ·     Ras Al Khair, Saudi Arabia: 1,036,000 m3/day
  • ·     Taweelah, UAE – 909,200 m3/day
  • ·     Shuaiba 3, Saudi Arabia – 880,000 m3/day
  • ·     Jubail Water and Power Company (JWAP), Saudi Arabia – 800,000 m3 /day
  • ·     Umm Al Quwain (UAQ), UAE – 682,900 m3/day
  • ·     DEWA Station M, Dubai – 636,000 m3/day
  • ·     Sorek, Israel – 624,000 m3/day
  • ·     Jubail 3A IWP, Saudi Arabia – 600,000 m3/day
  • ·     Sorek 2, Israel – 570,000 m3/day
  • ·     Fujairah 2, United Arab Emirates – 591,000 m3/day
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