Desalination is a common term for our science students. It is an interesting and useful process where seawater is made fit for drinking and irrigational purposes. As seawater is salty, it is desalinated to make it fit for human use. Scientists believe that seawater desalination can be an effective solution for dealing with increasing water scarcity. Desalination was commonly carried out in ships and submarines. In recent times, a lot of countries, including some states of the U.S., are rapidly using desalination on a large scale to meet their water needs.
In this article, we are going to discuss some of the facts about desalination.
- Desalination was invented by Thomas Jefferson (American); it was used by ships and vessels for drinking purposes when they ran out of stored water and in times of emergency.
- There are over 10 methods of desalination being used right now. Each method has different pros and cons.
- Vacuum distillation
- Multi-stage flash distillation
- Multiple-effect distillation
- Vapor-compression distillation
- Reverse osmosis
- Solar evaporation
- Electro-dialysis reversal
- Wave-powered desalination
- Thermal powered desalination
Reverse osmosis and thermal powered desalination are commonly used all around the world.
- San Diego city management has invested over a hundred billion dollars into a desalination plant, which will provide around 56 million gallon water to meet the city’s growing water consumption. This project is known as the Carlsbad Desalination Project. It was reported by sacbee.com.
- You would be surprised to know that Dubai, a famous tourist and business destination all over the world, gets 98% of the water through desalination. It was reported by Bloomberg.
- Reuters reported the following facts about desalination.
- The primary method of desalination is reverse osmosis. Water is pushed to pass through a very thin membrane with the help of energy. This membrane catches salts and other minerals. A high amount of energy is needed for this purpose of desalinating water in bulk. It is one of the major costs associated with the desalination process.
- Kingdom of Saudi Arabia leads the global output of water through desalination, followed by U.A.E. and the U.S. at 13.4 and 13%, respectively. Due to cheap energy, the Middle East has the most advanced desalination projects, and they don’t care much about their environment. We will discuss the impacts of desalination on our environment later in this article.
- In the U.S., inland brackish water desalination is 54% of the total desalination, and seawater accounts for 7.4%. Seawater desalination, at the time, is more costly, but it will be the major source of desalinated water with the advancement in technology and a decrease in costs.
- California has a desalination capacity of 83,000-acre-feet per year. It is equal to 11% of total water usage in L.A.
- Around 100 countries all over the world are using desalination plants to complement their water supply. The size of the project varies according to the cost they can put it. It was reported by Bloomberg.
- Desalination has been growing rapidly since the last century due to the decreasing cost of technology and the increasing cost of other sources. More countries and states are moving towards desalination. The following graph shows the growth from 1960 till 2020.
- Some 300 million people get their water through the process of desalination. Almost every country from the U.S. to China use desalination as a mean to get fresh water from seawater.
Some Drawbacks of Desalination
Energy Consumption – The process of desalination consumes a lot of energy. The waste products can harm our environment.
Costly – At present, desalination costs too much. It cannot be used by developing and underdeveloped countries until or unless the cost of setting up the plant and transporting water to cities is made affordable. The costs have decreased for developed countries and oil-rich countries in the Middle East.
Brine – The byproduct of desalination is brine. It is a solution with a double amount of salt and minerals and also contains chemicals used in the cleaning process in the membrane. When it is released in the sea, it causes water pollution.
Environmental Impacts – Desalination impacts our environment negatively. Either the process of reverse osmosis or thermal desalination is used; both produce thermal energy and contribute to global warming. When excessive heat is generated inside the sea, it disturbs the ocean life as well.
Viable for Coastal Cities only – The cost of setting up pipelines for non-coastal cities would be huge, and it would become impractical to spend such a large amount of money on this kind of project. Desalination is currently being used for coastal cities.
Impact on Marine Life – When brine is released back in the water, it can impact the life of fish in that area of the sea and disturb the ocean food chain. It can also be problematic for fishers as it can disrupt their livelihood.