Obtaining drinking water is an increasingly serious and key problem in the future of human development. We need a lot of water for both our consumption and irrigation. The surface of our planet is covered at 70% water, but less than 1% of this is suitable for human consumption. That is why it is so important to convert salt water from the oceans into drinking water, a process of the desalination plants. If you want to learn more about Seawater desalination methodsaccompany us in this ecology article in which we talk about What is desalination and their types.
What is desalination – definition
Desalination is understood as the process of Obtain drinking fresh water from seawater or brackish waterwhich is the one that has a salt content of between 0.5 and 30 grams per liter.
This process is carried out in Desalination plants of different types. It is not a novel concept, because this type of plants has been, but Desalination It is a process that produces numerous mineral waste and polluting substances, in addition to being quite demanding in its electricity consumption. Therefore, work is still working every day to find ways to optimize salinization processes and make them more efficient and sustainable.
To understand this topic much better, we recommend you read these other articles and see this video of Ecology Verde about:
- What is the water cycle.
- Why river water is sweet.
Types of desalination
Exist 5 systems to achieve water desalination On a large scale. Are the following:
Inverse osmosis
This is the most widespread of all current desalination systems, and also the most advanced. 60% of the current desalination is done by reverse osmosis.
The natural osmosis is that, if we have two mass of solution with the same solvent and separated by a semipermeable membrane, the solvent will go through osmotic pressure from the part with less concentration to the part with greater, until the concentration of both is equal.
In reverse osmosis what we do is apply pressure to force water to pass through that semipermeable membrane, which allows the passage of the solvent, but not from the solute, thus obtaining water free from the mineral salts dissolved in seawater.
The pegas of this system are the amount of energy it requires, and that it is necessary to obtain a volume of salted water to the triple from which we are going to obtain desalination. The use of graphene sheets that replace current membranes, and that theoretically give much better yields are being investigated.
Distillation
It consists of applying heat to the water to evaporate it and re -condensate it throughout different phases, which will give rise to desalted water. In addition, in this system it is possible to use the heat obtained in the condensation to heat new amounts of water to be distill.
Freezing
This process seeks to freeze water to create pure ice crystals, which we can then convert into fresh water. It is a more effective method than that of distillation, but currently at a disadvantage against reverse osmosis.
The most efficient method currently consists of using a refrigerant that, when expanding, freezes sea water and allows us to collect the clean ice crystals.
Lightning evaporation
This process, also called Flash Evaporation or MVF, consists in introducing water in the form of small thickness drops into a low pressure chamber, below saturation. This change causes part of the drops to evaporate immediately, and when they are condensed they give rise to desalinated water.
The leftover water passes to a next chamber, to an even lower pressure, so that the process occurs again. Some plants may have up to more than 24 stages of light desalination.
By electrodialysis
Permeable membranes are placed a few millimeters from each other, with electrodes at the ends. By allowing membranes, the selective ion step when there is a continuous electric current, alternately trapsing the ions of Na+ or Cl-, the components of the salt, thus achieving fresh water.
How a desalination plant works
If you wonder How a desalination plant workstake note that Desalination plants by reverse osmosis They follow this process.
- They begin their process by collecting seawater from underwater towers or coastal wells.
- This water is taken to the pretreatment zone, where solids in suspension, bacteria and microorganisms are separated from it.
- Then it is filtered using sand filters and coagulants, to move on to a microfiltration stage with cartridge filters with activated carbon or other similar products.
- From here it passes to the heart of the desalination plant, where the reverse osmosis process is carried out.
- The pressure pump forces water to pass through 7 semipermeable membranes, which let only water out, already free of salts.
- A post -treatment process is necessary, in which the water is remineralized so that it has the components and pH necessary for human consumption.
- The remaining brine retires from the reversal osmosis racks to return to the sea.
If you want to read more articles similar to Desalination: What is and typeswe recommend that you enter our category of other environment.
