Breaking the Energy Barrier: Water is an extremely important resource for life and plays a vital role in global social, economic, and environmental development. Although about 70% of the Earth is covered with water, the availability of fresh water is limited. It is a common misconception that water is abundant, but the reality is that a large part of the world’s population does not have access to regular and safe fresh water. Currently, about 110 million people do not have access to clean water, while about 270 million people face water crisis for at least one month in a year. If the current water consumption rate is taken into account, this situation may become more serious in the coming years. After 2030, about two-thirds of the global population may face water scarcity, which can also have serious impact on the ecosystem. According to data from the World Bank and FAO, about 200 million people in 44 countries may face water scarcity by 2050.
Water scarcity not only affects health and livelihoods, but it is also a serious challenge for economic development and social stability. Especially in vulnerable areas, water scarcity can adversely affect employment, agriculture, industry and quality of life. In such a situation, water purification or desalination technology emerges as a viable solution. Desalination is often called a “drought-resistant” water source because it does not depend on rivers or reservoirs and is not affected by the effects of climate change.
Traditional Desalination Techniques
Traditionally, desalination technologies have been divided into two major categories: thermal and membrane-based technologies. Thermal desalination involves heating sea or brackish water, followed by evaporation and condensation to produce fresh water. The process produces both high salinity brine and fresh water. The major thermal methods are: multi-stage flash (MSF), multi-effect distillation (MED) and vapor-compression evaporation. In MSF, water is boiled and converted into vapor by passing it through high temperature and pressure chambers, while in MED water is heated in several stages and the vapor from each stage is used to heat the next stage. Although thermal techniques are reliable, energy consumption is high.
As an alternative, membrane-based desalination technologies such as reverse osmosis (RO) and forward osmosis (FO) are also being widely adopted. In RO, salt water is passed through a semi-permeable membrane at high pressure, which allows fresh water to be separated. The energy consumption of this method is less than thermal technology and it is more modular and compact.
Solar Still is also a simple and economical option for supplying fresh water in rural and remote areas. In this, fresh water is produced through evaporation and condensation by heating water using the energy of the sun. Although its productivity is less than traditional desalination techniques, it can be made more effective by advanced design and combination of solar panels.
Emerging New Technologies
1. Solar Electrochemical Distillation (SED)
An important technology developed recently is Solar Electrochemical Distillation (SED). This technology purifies water by combining solar energy and electrochemical processes. Compared to conventional solar distillation, SED is more energy-efficient and environmentally friendly.
The SED system is composed of three main components: the solar absorber, the electrochemical cell, and the distillation unit. The solar absorber stores the sun’s energy and converts it into heat. The electrochemical cell consists of two electrodes (anode and cathode) with a membrane between them that allows ions to pass through. When salt water enters the anode, solar energy drives the electrochemical reaction and fresh water is stored in the cathode.
The key features of SED include its high energy efficiency, environmental sustainability, and cost-efficiency. The technology can be adopted on a large scale or as small, decentralized plants. It can be used for drinking water, agricultural irrigation, and industrial water requirements.
However, SED also has challenges, such as increasing the efficiency of the solar absorber, improving the performance of the electrochemical cell, and developing materials that can work under harsh conditions. Technological development and policy support can make SED systems more effective.
2. Integrated Solar Capacitive Deionisation (SCDI)
Another emerging technology is Integrated Solar Capacitive Deionisation (SCDI). This technology combines solar energy and capacitive deionisation. In this, a solar energy collector converts the sun’s energy into electricity and drives the CDI process. This method provides a particularly energy-efficient and sustainable solution, ensuring fresh water supply in water-scarce areas.SCDI and other hybrid systems have the advantage that they do not depend on conventional energy sources and can be easily implemented in plants of varying capacities. They can be adopted in both rural and urban areas.
Future Prospects
Emerging technologies in water purification and desalination can provide solutions to the global water crisis. As the population grows and the challenges of climate change increase, the need for these technologies will increase. Technologies such as SED and SCDI provide energy-efficient, environmentally friendly and economically viable solutions.
The efficiency and sustainability of these systems can be improved through future research and innovation. Policy making, investment and global cooperation can play a key role in the widespread implementation of these technologies. If these technologies are used properly, it can ensure sustainable, clean and safe water supply for future generations.
Conclusion
The global water crisis is a serious and growing problem for which conventional technologies are not sufficient to solve. Emerging desalination technologies, such as SED and SCDI, are not only energy-efficient but also environmentally friendly and economically viable. Through development, research, and policy support of these technologies, we can ensure water security and provide a sustainable supply of clean water globally.
