Water is an essential ingredient across industries, not just in the products but also in the preparation for cleaning the products, processing and other uses. While 71% of the earth’s surface is covered with water, only a tiny amount (0.6%) is fit for consumption.
The supply of clean and fresh water is fast decreasing. In contrast, the demand for consumption of water is fast increasing due to a growing global population, agricultural activities and economic development. Pressures from both the supply and demand sides, mean that clean water is increasingly becoming hard to source. While the future outlook for India’s capability to meet the growing demand seems to be grim, India can perhaps turn to its neighbours in the Middle-East to replicate their desalination model.
In the last two decades, desalination plants have evolved rapidly to extract fresh water from the sea. At present, nearly 150 countries rely on desalination plants to meet their fresh water requirements. The Middle-East and North Africa (MENA) region accounts for nearly half the world's desalination capacity, according to World Bank calculations, making it the largest desalination market in the world. According to Global Water Intelligence, the world’s desalination market is projected to reach $7 billion by 2022, with the Middle-East and North Africa region to account for $4.3 billion.
Middle-East’s desalination success story
Typically, in the desalination process, the source water (either sea or polluted water) is distilled using either thermal or electrical energy. This process removes salts (fluorides, chlorides, sulphates and so on) which are found dissolved in water, thereby rendering the source water fit for consumption (called distillate).
However, this process has one major drawback — it consumes a large amount of energy, which is traditionally derived from fossil fuels. Considering the fact that India is steering itself towards fossil-free energy generation, it would be practical to combine the shift towards renewable energy with desalination technique.
Set up over a decade ago by the Arabian Construction Company, the Shuweihat S1 Independent Power and Desalination Plant in Abu Dhabi, the UAE is currently one of the world's largest combined power and water plant complexes, delivering 1500 MW of power to the emirate of Abu Dhabi. The plant is linked to a seawater desalination facility which is supplied with steam from the turbines.
Similarly, in Oman, the desalination market in the country has been expanding by a little over 5% per year thanks to rapid urbanisation and population growth. South Korea’s Doosan Heavy Industries & Construction Co. will take part in a $203.9 million desalination project in Oman, the latest in its series as the world’s biggest desalination plant builder. The new desalination plant will be built in Sharqiyah region, 220 kilometre southeast of Oman’s capital, Muscat. The plant will be designed to use reverse osmosis method and will be able to supply 80,000 tonne of fresh water, enough to meet the water demand of 200,000 people a day.
Desalination is relevant in India
Potable water is scarce in India and has become one of the major challenges for the country today. According to a recent report by the National Institution for Transforming India, a policy think tank, about 200,000 Indians die each year due to inadequate access to potable water, with 600 million facing what is termed ‘extreme water stress.’ Furthermore, studies suggest that by 2030, the water demand in India will double. This would result in severe water shortages for millions of people.
India holds just 4% of the global freshwater, despite having nearly 16% of the world's total population. The ability to use seawater that most coastal states have access to is perhaps the most prudent solution.
Combining renewable energy-based technologies to power desalination plants will ensure that the production of pure water is non-polluting. The benefit of this scheme would be twofold. Firstly, clean drinking water would be produced to alleviate water stress. Secondly, the use of renewable energy-based plants will help abate the effects of climate change.
Current industry overview and steps
The most popular desalination technologies include Multi Effect Distillation (MED), Multi Stage Flash (MSF) and Reverse Osmosis. MED and MSF techniques are heat-based while reverse osmosis is a pressure-based technology using a membrane, similar to a filter paper, to separate salts from the raw water.
Over 70% of the thermal desalination plants have already shifted over to reverse osmosis technology globally. While looking forward, Adsorption Desalination (AD) is being researched and developed as one of the most energy-efficient processes. These can be powered by multiple renewable energy-based power systems.
The final combination of desalination technologies and their renewable energy-based power systems depends on factors such as source water availability, environmental constraints, location, distillation capacity and cost of desalination. However, cost and capacity are usually the key considerations.
The government is already working on implementing a desalination policy. At present, India has three operating desalination plants on the Lakshadweep islands. The country's topmost think-tank Niti Aayog has been planning similar plants across the country. Proposals for desalination plants at Tuticorin, Paradip and Kandla are also already under consideration.
However, not everyone is in favour of desalination. Effluent waste management from desalination plants including brine concentrate and other effluents pose huge concerns globally. Despite advancements made towards ‘zero liquid discharge’ technologies, where the brine concentrate is converted into solids fit to be disposed at landfills, the costs at present remain steep and must be taken into consideration to avoid any serious ecological complications which have occurred in the past due to poor planning.
Call to action
Ensuring access to safe water for the masses is the need of the hour. This essential resource is both limited and steps for course correction are still at a nascent stage. Freshwater sources are drying up quicker than the rate at which they are being replenished. Getting the desalination policy right would definitely be a shot in the arm for India’s long-term strategy to mitigate water stress and solve the country’s water problems.
