The world population is increasing exponentially. Stressing on existing natural water supplies continue to increase at a rapid rate. Various parts of the world are currently experiencing scarcity of water and water that is not viable for domestic purposes. This in turn effects food production and water borne diseases which turn fatal. This creates a wider space for research on alternatives to end scarcity of water.
Desalination is a process of removing mineral components from saline water. This can be achieved by various membrane filtration techniques and other conventional methods.
HOW CAN DESALINATION HELP?
Desalination can provide a source of drinking water which is climate independent (seawater desalination) however, the process requires a huge amount of energy and capital. The fresh water resources are depleting at a faster rate due to the sewage disposal and various other human activities. The World Resources Institute’s March 2016 report said 54 percent of India was water stressed, with scarcity affecting every part of the country except the Himalayan region and the ghats.
We are fortunate that our country has vast seawater resources covering large parts of over a dozen of states and union territories. The process would eliminate the situation faced by the people living near to the coastal region, having access to an inexhaustible supply of saline water but they cannot find the way to use it. The only process that can help in achieving the water requirements for the people is desalination. India has been trying to end the water demand problems by establishing desalination plants near Chennai, Pondicherry, Andhra Pradesh, Gujarat, etc.
Since the energy prices have been increasing from past century but overall capital and operating cost for desalination plants have declined due to advancements in research. According to Desalination Association of India, the production cost of a brackish water desalination plant could be Rs 10 to 15 per m3 while the production cost for a seawater desalination plant varies between Rs 40 to 50 per m3. This must be kept in mind that the cost depends upon total dissolved solids load. So while designing the desalination plant, one must keep in mind that the influent water to the plant should have low total dissolved solids content in order to save energy and capital cost. It must be also noted that conversion of seawater into desalinated water is about 10 paise per litre of water produced. Large scale plants can provide further reduction in the cost per litre conversion.
Critical factors which a product should consider
- 1. Easy usage.
- 2. Service support.
- 3. Rate of filtration.
- 4. Efficiency in removing taste and smell, etc.
Purification of seawater holds the key to development of a country's water resources reducing the production cost. Considering the geographical location of our country, it has ample renewable energy resources which can be utilised for the consumption of desalination plants (wind and solar). This will in turn reduce the energy consumption, thereby reducing the carbon footprint and hence will lead to sustainable development.