Desalination Plants In India - Desalination of SeaWater

Desalination Plants in India are an additional source of water for human use. Desalination of Seawater can help in meeting the freshwater demand of human and environment of a given area.

Desalination Plants – Why in the News?

On November 23rd 2020, Maharashtra Government gave a go-ahead to the Brihanmumbai Municipal Corporation for setting up of a desalination plant in Mumbai’s Manori to overcome the water crisis in Mumbai.

The topic is relevant for the general awareness section of various Government exams. 

Also, candidates preparing for IAS Exam might encounter questions based on Desalination plants in Prelims and General Studies Paper 3 of UPSC.

Hence, aspirants should go through the facts related to Desalination plants in India carefully.

What are Desalination Plants?

1. A desalination plant turns salt water into water that is fit to drink. 
2. These plants are mostly set up in areas that have access to seawater.
3. Saltwater is desalinated in the plants to produce water suitable for human consumption or irrigation

What is Desalination?

Desalination is a process that takes away mineral components from saline water. It refers to the removal of salts and minerals from a target substance (like soil desalination, an issue for agriculture).

1. The most commonly used techniques for the process is reverse osmosis where external pressure is applied to push solvents from an area of high solute concentration to an area of low-solute concentration through a membrane. 
2. The microscopic pores in the membranes allow water molecules through but leave salt and most other impurities behind, releasing clean water from the other side. 

Need For Desalination Plants in India

Major urban cities in India experience chronic water problem. The city receives water from ground and surface water sources that are insufficient against the existing demand. Also, due to an increased usage of groundwater, underground aquifers are being depleted at a rapid rate and the demand for water is expected to increase only in the future.

1. Currently, BMC supplies 3850 MLD as against the requirement of 4200 MLD each day. According to the projections, the population of Mumbai is anticipated to touch 1.72 crores by 2041 and accordingly, the projected water demand would be 6424 MLD by then.
2. The desalination project is expected to provide relief to the residents of Mumbai in tackling 10-15% water cut.

Desalination Plants – Strengths

1. It is capable to meet or exceed the standards for water quality,
2. Desalination plants can meet the demand for drinking water in areas where no natural supply of potable water exists.
3. It is a source to extend water supplies other than what is available from the hydrological cycle by providing an “unlimited”, climate-independent and a steady supply of high-quality water. For more information on the Hydrological Cycle, check the linked page.
4. Desalination plants can also reduce pressure on freshwater supplies underground aquifers.
5. The environmental problem can be changed into an economic opportunity as the byproduct of water desalination is Brine which can also contain precious elements like uranium, magnesium, strontium, sodium etc. which have the potential to be mined. 
   • Know more about minerals on the links provided below.
     

     Marine Mineral Resources	Rare Earth Minerals
     Physical characteristics of minerals	Mineral and Characteristics – geography notes

6. Brine has been used for aquaculture, with increases in fish biomass of 300%. It has also been successfully used to cultivate the dietary supplement Spirulina, and to irrigate forage shrubs and crops.

Desalination Plants in India – Current Status

Desalination has largely been limited to affluent countries located in the Middle East and North Africa regions, such as Saudi Arabia, the UAE, and Kuwait.

1. In India, Tamil Nadu has been the pioneer in using this technology, setting up two desalination plants near Chennai in 2010 and then 2013, while there are two more to come.
2. Maharashtra will be the 4th state in India to adopt the idea of setting up a desalination plant.
3. The other state that has proposed Desalination plants in Gujarat. It has announced to set up 100 MLD RO plant at the Jodiya coast in Jamnagar district. Other proposed desalination plants in the state are in the coastal areas– Dwarka, Kutch, Dahej, Somnath, Bhavnagar, and Pipavav. 
4. Andhra Pradesh is also planning to set up a desalination plant. 

Aspirants preparing for any government exams can visit the link provided to prepare even better for the examination-

1. Free Online Quiz for Government Exams
2. Government Exams Free Mock Test Series
3. Government Exam Previous Year Question Papers with Solution PDFs

Desalination Plants – Weaknesses

1. The environmental impact is a major disadvantage to water desalination plants. Disposal of the salt removed from the water is a major issue. Read about Environmental Impact Assessment on the linked page.
2. Desalination is an expensive way of generating drinking water as it requires a high amount of energy. The high cost of setting up and running a desalination plant is one reason why the government has been hesitant in building such a plant.
3. Energy costs account for one-third to one-half of the total cost of producing desalinated water, so the cost is also greatly affected by changes in the price of energy.
4. The discharge brine, can change the salinity and lower the amount of oxygen in water leading to stressing or killing of animals. 
   • Read more on Salinity of water on the links provided below-
     1. The salinity of Ocean Water
     2. Horizontal and Vertical distribution of Salinity
5. Numerous chemicals such as chlorine, hydrochloric acid, carbon dioxide, and antiscalants are produced in the desalination process that can be harmful in high concentrations. Know more on Hazardous substances at the given link.
6. It can end up severely damaging the local ecology around the plants.

Desalination Plants – Way Forward

1. There is a need to make desalination technologies more affordable, i.e. increasing the viability of desalination for addressing Sustainable Development Goal 6 (SDG-6: Ensure Access to Water and Sanitation for All). Read more on Sustainable Development Goals on the linked page. 
2. To do this, technological refinement for low environmental impacts and economic costs, along with innovative financial mechanisms to support the sustainability of desalination schemes, will likely be required.

Other Related links

Aspirants preparing for the UPSC exam can check the links given below –

1. UPSC 2021
2. UPSC Calendar 2021
3. UPSC Syllabus
4. Analysis of the Press Information Bureau
5. NCERT Geography Notes for UPSC
6. UPSC GS III Syllabus, Structure & Strategy

You can also check out the preparation strategies for competitive exams to fine-tune your exam prep.