Recently, Maharashtra has declared its plans to establish a desalination plant in Mumbai.This strategic move aims to address the water shortage encountered by the city during the sultry months of May and June. With this initiative, Maharashtra joins the ranks of states experimenting with desalination plants. The process involves converting 200 million litres of water every day (MLD) from saltwater to freshwater.
Understanding Desalination Plants
At its core, a desalination plant transforms saline water into potable water through a process called desalination. This procedure involves eliminating salts from the water to make it suitable for various human applications. The most frequently employed technology for this process is reverse osmosis.
During reverse osmosis, an external pressure is exerted to drive solvents from a section of high solute concentration to another with low concentration through a semi-permeable membrane. The tiny pores in these membranes permit water molecules to pass but retain most other impurities, including salt. Consequently, refreshing water is released on the other side. Typically, desalination plants are primarily established in regions with access to seawater.
Benefits of Desalination Plants
Desalination plants can significantly enhance water supplies beyond what the hydrological cycle provides, offering a steady, climate-independent, and endless supply of premium water. They can also offer drinking water in regions where there’s no natural source of potable water. By consistently meeting or surpassing water quality standards, these plants can alleviate the pressure on freshwater supplies originating from overexploited resources.
Drawbacks of Desalination Plants
Building and operating desalination plants can be costly, mostly because they require considerable amounts of energy. Energy costs make up about a third to a half of the total expense of producing desalinated water. Moreover, the cost is subject to fluctuations in energy prices. Beyond financial implications, desalination plants also pose environmental concerns. For instance, disposing of the extracted salt or brine can alter salinity levels and reduce oxygen concentration at disposal sites, causing harm to marine life.
Converting Environmental Challenges into Opportunities
The environmental predicaments associated with desalination plants can be turned into economic opportunities. For instance, the discharged brine could contain valuable elements like strontium, uranium, sodium, and magnesium that can be mined. There have been instances where brine has showcased potential in aquaculture, contributing to a 300% uptick in fish biomass. It has also shown promise in cultivating dietary supplements like Spirulina and irrigating forage shrubs and crops.
Application of Desalination Plants in India
Traditionally, desalination plants have found favor in Middle Eastern countries, parts of Australia and the United States. In India, Tamil Nadu trailblazed the usage of this technology by setting up two desalination plants near Chennai in 2010 and 2013, respectively. Gujarat and Andhra Pradesh are other states considering similar projects.
Moving forward
To ensure the Sustainable Development Goal 6 (SDG-6: Ensure Access to Water and Sanitation for All) is met, there’s a need to make desalination technologies more affordable. Doing so would necessitate technological refinements to limit environmental impacts and economic costs. It’s equally important to look at innovative ways to finance such initiatives, ensuring their viability and sustainability in the long term.
