DESALINATION

Desalination must have a number of advantages, including:

• Providing drinking water: Provides access to drinking water in regions where drinking water is limited.
• Diversity of water supply: Diversification of water supply reduces dependence on natural water sources, such as rivers and lakes.
• Reducing the need for water transport: Desalination can reduce the need to transport water from other regions.

With technological advances, the prices of drinking water production from desalination have decreased, making this technology increasingly accessible and sustainable. Desalination remains an important tool for securing water supply in regions with water challenges.

One cubic kilometer of seawater contains about 40 million minerals, total dissolved solids (TDS) – cations: calcium, magnesium, sodium and potassium, and anions: carbonates, bicarbonates, chlorides, sulfates and nitrates – increase the electrical conductivity of water and corrosion, and give an unacceptable taste. The process of membrane desalination of water – when separating two fluids of different concentrations (e.g. pure salt-free water and salt solution) through a semi-permeable membrane.

Desalination systems are divided into two groups, depending on the water quality:

1. Brackish water desalinators (from 3,500 – 15,000 ppm NaCl)

2. Seawater desalinators (from 20,000 – 45,000 ppm NaCl)

The reverse osmosis (RO) desalination process is a technology increasingly used to convert salty seawater into drinking water. Osmosis is a natural process where water moves through semi-permeable membranes to equalize the concentration of salts on both sides of the membrane.

Reverse osmosis uses this principle to force salt water through the membrane by force, leaving salts and impurities on one side, while pure water is collected on the other side of the membrane.

Description of the process of desalination by osmosis:

1. Taking sea/brackish water: Seawater is first taken as a raw material for desalination. This raw water contains various salts, minerals and impurities.
2. Pretreatment: Before seawater enters the desalinator system, it undergoes pretreatment to reduce the concentration of particles, suspended substances and other impurities. This prevents clogging of membranes and improves the efficiency of desalination processes.
3. High-pressure pumps: Water passing through the membrane increases pressure to create a force that forces salt water to pass through the membrane. High-pressure pumps create the pressure required for this desalination process segment.
4. Desalinator membranes: Salt water under high pressure is forced through the reverse osmosis membrane. This membrane has microscopic pores that are small enough to leak only water molecules, while larger salts and impurities remain retained.
5. Drinking water -result: Through the process of reverse osmosis, salt water loses its salts and impurities, and clean water passes through the membrane. The result is fresh water, which is almost completely free of salt and other impurities.
6. Concentrated salt water: Salt water that has not passed through the membrane, along with all salts and impurities is drained as waste concentrated salt water.
7. Correction and mineralization: Clean water that has passed through the membrane can be further stabilized and improved quality through additional steps such as remineralization, disinfection and pH correction.

The reverse osmosis desalination process requires precise control of parameters such as pressure, flow rate and temperature to achieve high efficiency and quality of the resulting fresh water.

Although this process requires the amount of energy to create the necessary pressure, advances in technology and energy efficiency contribute to the wider use of reverse osmosis to desalinate the sea and provide drinking water in regions of the world.