29 November 2024
World Water Series – How Technology is Making Saltwater Drinkable – Desalination
Saltwater is one of the most abundant water sources on Earth. Whilst it is perfect for sea creatures and recreational activities, its high salt content makes it unsuitable for direct human consumption and most industrial uses.
In our latest blog we will explore desalination, a solution many places worldwide have adopted and what two technologies are used: Distillation and Reverse Osmosis.
History of Desalination
Desalination dates to over 3000 years ago. As far back as the Bronze Age, ancient civilisations, mostly those on boats, would boil the Mediterranean Sea water and use sponges to absorb the steam, which created potable water.
Distillation: How it Works
Distillation is one of the oldest methods of desalination. It involves heating saltwater until it turns into water vapour, leaving the salt behind. The vapor is then captured, cooled, and condensed back into liquid form, now free of salt.
Reverse Osmosis: A More Efficient Solution
Reverse osmosis is a more modern and efficient method of desalination. Seawater undergoes a pretreatment to remove debris or particles that could damage the filter membranes. Then, high pressure forces the water through specialised membranes allowing water molecules to pass through while blocking salt and other impurities.
One side of the membrane you get purified water and on the other, a concentrated brine is left behind. Reverse osmosis is also highly effective at removing microparticles, bacteria, and other contaminants.
Why Use Saltwater
As populations grow and the demand for freshwater increases, natural resources may not be able to meet the demand. Desalination offers a reliable alternative.
The world’s first large–scale thermal desalination was built in 1928, since then many more have been constructed. For instance, the Hadera plant in Israel and the Cape Preston in Western Australia. Hadera, the largest plant in the world, can produce enough potable water to provide for a million households per year. At Cape Preston, where vast deserts meet the ocean, construction of its plant provided an essential solution. Due to the location, it came pre-assembled by boat from China using designs from Israel. The desalination plant is providing water to generate power for the world’s largest iron ore mine.
Advantages and Disadvantages
Advantages:
- Reliable Supply: Desalination can provide a dependable source of water for households, cities, and industries, particularly in areas where freshwater is scarce.
- Large-Scale Use: Plants like Hadera in Israel and Cape Reston demonstrate how desalination can support the water needs of large cities and industries.
Disadvantages:
- Energy-Intensive: Both desalination methods require significant energy to operate, leading to higher costs and environmental impacts.
- Environmental Concerns: The leftover brine, a highly concentrated salt solution, is often discharged back into the ocean, where it can harm marine ecosystems.
However, there are efforts to mitigate these impacts. Some companies like one in Denmark, are using solar power and filter the water differently which reduces the salt content of the leftover brine, making it only slightly saltier than surrounding seawater. Other plants are experimenting with storing excess energy or releasing brine in deeper ocean layers to minimize environmental damage.
In Conclusion
Desalination offers a promising solution to the growing water crisis, with advances in technology making the process more efficient and environmentally friendly. While the energy demands and environmental concerns are challenges, innovative solutions are being implemented to address these issues.
Whether you are interested in large-scale desalination or looking for ways to conserve water at home, rainwater collection and storage systems are also an excellent option. Explore our range of slimline, round, or firefighting tanks on our Orion Australia website to help reduce water costs or water scarcity.
