What is Desalination? Its Purpose and Method along with Pros and Cons.

Desalination is the process to take away mineral components from saline water. The process refers to the removal of salts and minerals from a targeted substance because desalinated water gives an issue for agriculture. Saltwater is purified by the process of desalination to produced filtered water that is later on used for human consumption and irrigation purposes. Desalination is also being used on many seagoing ships and submarines. Due to its energy consumption, desalinating sea water is costly than fresh water from rivers, water recycling, and water conversion. Currently, roughly 1% of the world’s population is dependent on desalinated water to meet daily basis. According to the International Desalination Association about 18,426 desalination plants operated worldwide that produce 86.8 million cubic meters day, providing water for 300 million people.

What is the purpose of desalination plant?

The primary purpose of the desalination plant is to filtered saline water that is further used for human consumption and irrigation purposes. The desalination plant converts salt water into fresh water. Another purpose of the desalination plant is to make water accessible in those areas that have limited resources of clean water. It provides a reliable and safe supply of water to growing communities. It also provides a ready and reliable alternative source of water in times of severe drought and also useful when there is a water shortage.

The best method of desalination

There are several methods for desalination of salt water into fresh water. Each process has Pros and Cons, but all are useful at the same time. The old process that is known as the traditional method of desalination is distillation, i.e., boiling and re-condensation of seawater to leave salt and impurities behind. 10 ways that are being used in desalination of water are as follows:

  1. Solar distillation
  2. Vacuum distillation
  3. Multi-stage flash distillation
  4. Multiple effect distillation
  5. Vapor-compression distillation
  6. Reverse osmosis
  7. Freeze-thaw
  8. Electro dialysis membrane
  9. Membrane distillation
  10. Wave-powered desalination

All methods of desalination are being used at different times. Three ways are shortlisted as the best methods of desalination. If we control experiments for volume, type of salt water and length of experiment time, then thermal distillation will be most effective, but cryo that is also known as freezing desalination will be most efficient in cost, time and energy, but the fact is cryo method will desalinate water completely. The thermal distillation is effective, however inefficient because of the amount of energy required, and it requires much time to desalinate the salt water and the amount of water lost to evaporation. In short, every method has advantages and disadvantages too as well. So one can choose the method according to need.

Advantages of desalination

Three major advantages of desalination are:

1: Provides potable water to people

The biggest and the essential benefits of desalination is that it provides pure water to people by desalinated salt water. It removes dissolved salts and other minerals from seawater that turned into fresh water that is ideal for drinking.

2: Provides water to the agricultural sector

Desalination provides not only fresh water to people, but also provide potable water that is used for irrigation purposes, which is great for arid regions as well as areas that are going through a drought. With potable water, farmers can produce their own food for their residents.

3: Tried and tested technology used

As we all know that there are many purifying processes available in the market, but the desalination process is beneficial and been in use for several decades. Because of this, it is considered to be a safe, workable, and reliable process that has been tried and tested in many applications by numerous experts over the years.

Disadvantages of desalination

Three significant desalination disadvantages are as follows:

1: Consumes a large amount of energy

According to many researchers, it is not a feasible solution to water supply problems mainly because it requires a large amount of energy. For example, in the process of distillation billion gallons of salt water is needed to be boiled at high temperatures before it can become potable.

2: Costly

Desalination plants required a large amount of money because of the equipment and machines they need and it can range between $300 million to almost $3 billion. According to studies, desalination water is five times more expensive to harvest than fresh water that makes it too costly for the average consumer.

3: Harmful for environment

Desalination water as we all know, remove salt to provide fresh water. The problem with desalinated water is that chlorine and other chemicals are often added to the water during processing and left behind with the brine which, if dumped back to the ocean, brings with it many harmful substances that can destroy the marine ecology.

Is desalinated water healthy?

Desalination is key to providing fresh water to millions of people around the world. There are two ways in which salt water is made fit for human consumption. One is thermal desalination, and the other is reverse osmosis. Once the water is purified, minerals and chemicals are added to meet the standards required for safe and healthy drinking water.

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