Desalination, the process of removing salt and other minerals from seawater in order to make it usable for drinking and irrigation, is a technically complex and costly process. There are a few key reasons why it is difficult:
First, the sheer volume of seawater that must be processed in order to produce a significant amount of freshwater makes desalination a significant engineering challenge. The amount of energy required to pump and treat such large volumes of water is substantial, and the cost of building and maintaining the necessary infrastructure can be high.
Second, the high salt content of seawater creates several technical difficulties for desalination. The salts and minerals present in seawater can damage or clog the membranes and other equipment used in desalination and must be removed or separated from the water before they can be purified. The saline water is also corrosive to many materials making the design of plants difficult
Third, the cost of desalination can be high, especially when compared to other sources of freshwater. The energy required to power the desalination process, as well as the cost of building and maintaining the necessary infrastructure, can make desalination more expensive than alternatives like groundwater pumping or surface water treatment.
Fourth, environmental concerns also play a role in the difficulty of desalination. The process can have a significant impact on marine life, and the discharge of concentrated brine back into the ocean can harm the local ecosystem.
Despite the challenges, desalination is a viable option in arid regions where other sources of fresh water are scarce or where the demand for water is high. Advancements in technology have helped to make desalination more efficient and cost-effective, and research is ongoing to find new and better ways to desalinate water.
Overall Desalination is an energy and capital-intensive process, it also has an environmental impact on ocean ecologies which makes it difficult to implement and costly to run. However as the world population is growing, freshwater scarcity becoming a major concern for many regions, and climate change making traditional water sources unpredictable, desalination technology has to be improved to meet the need for fresh water.