We may not realize it, but humans use a lot of water. Activities like drinking, agriculture, sanitation, and electricity generation all require significant amounts of water. And all of this water consumption contributes to the ever-growing threat of water scarcity.
This reality has led many world leaders and organizations to consider other options to fight the water crisis, and one option is ocean water desalination. Could humans one day drink sea or ocean water? It’s a possibility! Although the technology is not new, many are unfamiliar with this filtration method.
As your resident resource for all things water, The Science of Water is happy to break down what desalination is, how it works, and the pros and cons of using this water filtration method.
What is Desalination?
In simple terms, desalination is a scientific process that removes minerals, primarily salt, from water sources. There are three types of desalination technologies used to filter the saline water: membrane, also known as reverse osmosis, thermal distillation, and electrical. The main uses of desalinated water are for providing freshwater for human consumption in water insecure areas of the world and as irrigation for agriculture. Desalination is also used on seagoing ships and submarines that don’t have access to clean water while aboard those vessels.
What makes desalination so popular are the possibilities it brings. According to the United Nations, around one percent of the world’s population relied on desalinated water for survival. The intergovernmental organization fears that water scarcity will result in that number jumping to 14 percent by 2025. This process is the lifeblood of countries like China, India, South Africa, and Kuwait.
As you can see, there’s a lot of hope that desalination can help solve the world’s water crisis. Let’s dig a little deeper into how the process works.
How Does it Work?
There are three principal water desalination methods in existence: thermal, electrical, and pressure. Because there are multiple ways to desalinated water, it’s advised that you factor in things like the water source’s quality and the size of the water source before choosing an option.
Thermal Distillation
Believed to be the oldest of the three desalination methods, thermal distillation is when saltwater is boiled, and the steam is collected, leaving the salt behind. The saltwater’s vaporization stage requires a ton of energy, which creates a strain on the environment and the economy. However, the modern version of this method uses low-pressure vessels to reduce the boiling temperature, which reduces the amount of energy needed to filter the water properly.
Reverse Osmosis (Pressure)
Hailed as the most popular of the desalination technology, reverse osmosis works similarly to the filtration system used in Puronics’ residential systems. It was developed in the 1950s and uses pressure to drive saline water through a semi-permeable membrane. As the water passes through, contaminants like salt, which are made up of larger molecules, get left behind. The amount of energy required to desalinate water through this technology depends on the amount of salt in the water, which sparks energy consumption concerns when used on larger water bodies like ocean water.
Electrical
This jolting desalination method uses an electrical current to separate the salt ions from the water. When the current touches the water, it pushes the water through a selectively permeable membrane, removing the dislodged salt ions. Unlike the other two technologies, the energy requirements depend on how much salt is present in the water. Although it’s highly effective at filtering water, it’s most suitable for smaller saline water sources.
Pros and Cons
Pros
Endless Supply of Water
The Earth is 90 percent water, which means a seemingly inexhaustible water supply that many countries can tap into to provide fresh water for their communities. The goal is to find new water sources and technologies that can resolve the world’s water scarcity issue, and the potential solution literally surrounds us!
Accessible Drinking Water
The most significant benefit of desalination is that it provides accessible drinking water. The clean drinking water it produces isn’t just limited to water insecure areas; it can supply fresh water to desert-stricken countries, regions experiencing drought, or impacted by a natural disaster. For example, Saudi Arabia and other Middle East and Northern African countries, get 70 percent of their freshwater through desalination.
Provide Water to the Agricultural Industry
A secondary benefit to having access to clean drinking water is that desalinated water is also safe to use in agriculture. Farmers who don’t have direct access to a steady water supply can now use it to rinse plants and provide their livestock with water. Desalination also has the potential to improve the economy of water in insecure countries. Because they can grow their own crops, they don’t have to rely so heavily on imports.
Cons
Energy Costs
Although water desalination is exceptionally useful, its energy consumption makes it one of the more costly methods, unlike water recycling. As mentioned in the previous section, the amount of energy required depends heavily on how much salt is initially present in the water supply. And as we know, ocean and seawater are among the saltiest bodies of water known to man.
Potential Harm to Marine Life
As regions began building desalination plants, one of the many concerns that cropped up was, “what are the side effects of desalination?” The answer is tons of leftover sodium-concentrated brine. A study by the United Nations Institute for Water, Environment, and Health found that the problem with brine waste was significantly underestimated (try 50 percent!) and that toxic chemical poses a potential pollution problem. Some also worry that the salty solution will get dumped back into oceans and seas, ultimately killing marine life.
Expensive to Build and Maintain
Currently, there are approximately 16,000 desalination plants in the world. Those don’t come at a comfortable cost. These plants can cost between $30 and $240 million to build and operate, and that doesn’t include the equipment and proper training needed for employees to do their jobs efficiently. Desalination plants are also speculated to be five times more expensive to harvest than freshwater, which can pose a challenge for communities in need who simply can’t afford the massive sticker price.
The Science of Water
Although desalination can do a lot of good, many are divided on whether its pros outweigh the cons. New technologies get created every day to help balance the scales and provide a solution to water scarcity. It may be years before the world adopts a water filtering technology like desalination, but you can benefit from reverse osmosis today with a Puronics whole house water filtration system installed by The Science of Water. We have more than 35 years in the water industry, and after taking one of our free water tests, we can help you solve the water issues that plague your home.
Want to request a free water test or learn more about our services? Contact our team at (352) 745-7070 or (904) 580-0000.