Using the sea to solve the world’s fresh water problems
This article was taken from another site (see link below) and posted on this blog by Leonardo Santos for EDUCATIONAL PURPOSES
Some parts of the world are very dry. In these areas, it is not easy to have enough fresh water for drinking and for growing food. In coastal areas, one idea is to get drinking water from the sea. There is certainly a lot of water in the sea. So it may seem like a very good idea to take the salt out of it in order to get drinking water.
In some dry areas, people do obtain fresh water from sea-water. This happens in the rich countries of the Middle East, such as Saudi Arabia. They have big desalination plants where the salt is removed from the sea-water. The fresh water is carried to towns and cities in pipes. Why don’t other dry countries do the same?
|There is a lot of it!|
One reason is that it is not cheap to remove salt from seawater. A big desalination plant uses lots of energy. This means that the cost of producing fresh water is high. In places like Saudi Arabia there is a lot of oil, so energy is not a problem. Producing fresh water in this way also puts a lot of greenhouse gases in the atmosphere. This causes problems for the environment.
This is why the WWF is against the use of big desalination plants. The WWF says that we should find other solutions to the water problem. For example, we should try to waste less water and find better ways of distributing water.
Another problem is that desalination plants sometimes kill fish. When the seawater is taken into the desalination plant, sometimes fish are taken in as well. Not all the salt can be taken out of the seawater. This means that at the end of the process, we have some water that is very salty. If we put this very salty water back into the sea, it could kill fish and other sea animals.
But a lot of scientists are sure that they can solve all these problems. They believe that we can get fresh water from the sea without causing problems to the environment.
First of all, new technology has reduced the cost of producing drinking water from sea-water. Less energy is needed. So there is less harm to the environment. It is also important to remember that there is really a lot of water in the sea. The sea can give us a permanent supply of water.
|Arid areas need fresh water|
In Australia, there are often periods without rain. Often there is not enough fresh water. This is why scientists and engineers are very interested in desalination as a way of getting enough fresh water. Recently, a big desalination plant was built near Perth. The plant produces about 40 million gallons of drinking water every day. This is about 40% of the total amount of water that is needed for the people who live in Perth. The desalination plant does not harm the environment. It uses wind energy to produce the electricity that it needs. Water is taken slowly from the sea. In this way, fish are not taken into the plant by mistake. But it only takes 30 minutes to produce drinking water from sea-water.
This method of producing fresh water from seawater could be used in other parts of the world. Gary Crisp of the Western Australia Water Corporation says: “I think that the new desalination plant will be able to supply half of Perth’s fresh water in the next 30 years. Desalination plants like ours could provide a solution for dry parts of the world.”