What is evaporation? Evaporation occurs two ways. One happens as part of the natural water cycle and is directly related to the sun’s heat. The other is by means of intentionally boiling or heating any liquid.
Evaporation plays an important role in the water cycle. As the solar energy from the sun turns surface water into vapours, the vapours rise and form clouds which then can produce more precipitation and more water for us here on Earth to enjoy, plant and animal alike.
In some parts of the world like Australia, it’s important to find ways to reduce evaporation with such low precipitation and high evaporation rates. But harvesting the water and trying to store it through dams is contributing to a loss of 40% of their water volume a year.
Water is a precious resource on Earth. Without fresh water communities could not develop and it’s absence dramatically lowers living standards. Communities in Australia began to run low on groundwater and needed to invest in finding new ways to supply people with fresh water. They looked to the desalination of sea water. Oceans hold 97% of the world’s water supply. Building desalination plants was a viable option and could benefit the country greatly.
Evaporation plays a key role in desalination. Distilling water to remove the salt and other chemicals found in sea water occurs by heating the water and turning it to steam. The steam is harvested while the salt and other hard minerals are left behind.
However there is another technology being put to use already in desalination plants in Australia called reverse osmosis. This process uses membrane filters with water being pushed through at a very high rate of pressure. The water moves through the membrane but again, the salt and other hard minerals are left behind.
What concerns some is how either type of desalination plants are powered. If they are still using fossil fuels to create the energy needed to desalinate sea water it is not an efficient nor sustainable system. However solar energy has had success supporting both traditional distillation and membrane distillation.
Another technology that uses evaporation helps us control unwanted saline water discharge to farm lands that are closer to groundwater catchments along the coast. An Evaporation basin can be placed in a designated area which is basically just a large excavated area. It is stripped of raw materials and then filled with sand and gravel that promote evaporation as the salt water collects there. These basins can be zoned commercially and be used to harvest salt. It does lessen the environmental effects of off site draining. If designed, built and placed correctly an evaporation basin can be an efficient war to dispose of saline groundwater that effects our cultivation of coastal lands.
Evaporation helps keep both our water and our soil free of salt so that we can benefit from an abundant fresh water supply and more coastal farms. -KATIE FLYNN