Turning Salt to Water
Author: Zoe Anders, ecological adviser, author of the project @sfera_lesa
Alternative technologies of the freshwater supply
Nowadays it is inarguable that free access to freshwater is a basic human right. However countries with mutual borders and as a consequence mutual water supply fight for resources as soon as it in a way guarantees power and political prosperity. The level of preservation still is very low, we can see how polluted or unconsciously used water sources can be, as some territories are too rural to have proper water supply. The other thing is that around 97,5 % of all the water on the planet is saline, which means that only 2,5 % of the whole volume can be considered as fresh. Taking out more than 1% of that quantity for glaciers and ice caps and we’re left with 0,83%. Many of the water systems that keep ecosystems thriving and feed a growing human population have become stressed. Rivers, lakes and aquifers are drying up or becoming too polluted to use. More than half the world’s wetlands have disappeared. Due to the system's inefficiencies, the agricultural sector consumes and (sadly) wastes more water than any other source. Climate changes also bring in a pack of problems, causing shortages and droughts on some territories and floods in others. It ends with the issue that around 1.1 billion people lack access to safe drinking water around the world, and a total of 2.7 billion find water difficult to access for at least one month of the year and around 4 billion people experience severe water scarcity at least one month of the year. At the current consumption rate, this situation will only get worse. According to some estimates, as much as two-thirds of the world’s population will face water shortages by 2025.
For that some governments for years have been developing new points of view on the whole freshwater supply systems. The key approach to getting rid of the excess substances from salt and brackish water appeared to be desalination.
Mainly, there are two technologies broadly used for desalinating water. One is reverse osmosis which can be basically explained as a process when salted water is being pushed through a system of membranes (with microscopic pores less than a hundredth the diameter of a human hair) at a pressure of 70 atmospheres. This technology used to be pretty expensive, but during 40 years it was optimized by the development of low energy consumption and actual membrane’s configuration which helped to reduce the desalination costs significantly.
Modern reverse osmosis desalination plants already operate close to the thermodynamic minimum energy demand, making it difficult for other technologies to compete.
Alternatively, other technologies are based on thermal desalination processes such as evaporation also known as multi-stage flash distillation. Compared to evaporation based desalination, membrane distillation and extractive desalination using thermoresponsive solvents can operate at lower temperatures. This enables the usage of low grade heat sources such as geothermal, solar, or industrial waste heat and offers the potential of avoiding the combustion of fossil fuels to reduce the carbon footprint.
Here are some of the countries that already have faced a clean water shortage and successfully overcame it with help of the above mentioned technologies.
The kingdom of Saudi Arabia fairly can be named the first country that has put a sight on desalination technologies. From the beginning of 20th century they were looking for solutions due to the desert climate. For that reason nowadays daily production capacity of 48 (!) desalination plants is 117 million cubic feet (three million three hundred thirteen thousand sixty nine cubic meters). As well as that the country has the largest floating desalination plant in the world Al Jubail with a capacity of producing up to 882,867 cubic feet.
Another leader of desalination, again due to climate peculiarities is the UAE. It’s primary source of freshwater used to be aquifers. But most of the water sources there appear to be saline and in some cases the water from the aquifers is up to eight times more salinity than seawater. So the Abu Dhabi government in a partnership with foreign investors have heavily invested in desalination of sea water and as a result has established eight desalination plants in the Gulf state with capacity of 7.23 million cubic meters per day.
Al Jubail, Saudi Arabia. Desalination plant, considered the largest in the world
One more example in the row from the Middle East is Kuwait. Geographically it has no fresh water sources as well as rivers or any other origins. And in that Kuwait could probably compete with Saudi Arabia. The country is known for being the first in history to establish a desalination plant for the large-scale supply of clean water in the middle of 20th century, 1951 to be precise. At the moment Kuwait’s desalination plants have a daily capacity of producing 58.3 million cubic feet (one million six hundred forty two thousand three hundred seventy six cubic meters), where around 90% is generated through multi-stage flash distillation and 10% is produced through reverse osmosis. In 1965, the government commissioned the construction of a water-supply system which is pictured in world-famous Kuwait Water Towers, a water facility of the capital with a storage capacity of 3,602,096 cubic feet (one hundred one thousand ,nine hundred ninety nine cubic meters)
The last but not the least part of the selected countries is Israel - as the youngest desalination ally. In the beginning of 2000 Israel had that huge water supply stress so had to apply for help from its Mediterranean neighbor –– Turkey. The agreement between countries could cover 5% of Israel’s needs for 20 years. Amazingly during the next five years the country developed and implied the system which at least helped to consciously use offered water resources. In 2007 the national water authority built innovative water treatment systems that recapture 86% of the water that goes down the drain and use it for irrigation. For instance Spain is considered the second most efficient country in the world – that recycles only 19%. And during the next 15 years the country managed to build five desalination units whose average annual production capacity by 2020 was approximately 100 million cubic meters. In 2022 Israel and Jordan agreed to partner in a project that would see Jordan build 600 megawatts of solar generating capacity to be exported to Israel in return for the additional water supply. Approximately 200 million cubic meters of water - the same amount consumed by the five biggest cities in Israel combined - will be supplied to Jordan.
Sorek desalination plant, Israel
However time and overloaded pursuit of progress bring more and more challenges to humanity. We still have chances to develop efficient sources management systems to help nature around us at the lowest expectations not to become extinct too fast. Next time we will have an overview of the regions that are more than close to a fresh water crisis and will take a look at the ways countries are undertaking in view of water shortages.