Working with Seawater: Desalination for industrial use

Numerous water-related issues have been afflicting India, including the rapid depletion of freshwater sources. Facto­rs such as unchecked disposal of waste, rampant discharge of sewage and industrial effluents, and large-scale deforestation along the basins have also constricted the capacity of rivers to meet the growing demand for water. According to a recent report by the Central Wa­ter Commission, Ministry of Jal Shakti, the ave­rage annual per capita water availability in India declined to 1,486 cubic metres (cum) in 2021. It is expected to further decline to 1,367 cum by 2031.

With increasing population density and urbanisation, water stress indices are increasing in cities such as Kolkata, Chennai and Del­hi. The rising demand for water from various industries is also creating pressure on freshwater sources. The high industrial penetration in coastal states such as Tamil Nadu, Gujarat and Andhra Pradesh is creating problems of water scarcity due to poor river water availability, low groundwater levels and high demand. With the growing demand for water fr­om industries, the government and other sta­keholders are taking desalination measures water supply to industries.

Market trends and developments

Given the restrictions on water extraction in some regions in the country, industries are ex­ploring alternative means such as desalination and recycled wastewater. A number of urban local bodies are also supplying secondary tre­a­ted wastewater to industries for non-potable pu­r­poses. According to India Infrastruc­ture Research, all key industries have experienced a positive growth in water consumption. The wa­ter consumption in the textile industry has inc­reased at a compound annual growth rate (CAGR) of around 12 per cent from 2015-16 to 2020-21. This is followed by the cement industry, which reported an increase of around 3 per cent, the steel industry by around 2 per cent, and oil and refineries by around 1 per cent.

Desalination in India was started with a slew of industrial desalination plants and pilot projects. The current overall desalination capa­city in India is estimated at over 620 million litres per day (mld), as per India Infrastructure Research. The industrial segment accounts for a 67 per cent (around 418 mld) share in the total desalination capacity in India.

Many industrial desalination plants are being set up in the country. The Andhra Prade­sh government has planned to set up desalination plants for industrial zones. The first plant is planned in Srikakulam district and will entail an estimated investment of around Rs 4 billion. This plant will be set up in the industrial zone of Ranasthalam mandal, Srikakulam district. About 26 major pharma industries, including Reddy Laboratories and Aurobindo, are operating in the region. All these pharmaceutical in­dustries depend on groundwater, which results in contamination of drinking water in the re­gion. The Andhra Pradesh Industrial Infrastr­ucture Development Corporation has been directed by the government to take up the project in PPP mode.

Many industries in sectors such as  power, refinery, and textile as well as industrial corridors and clusters are expected to create a market for desalination plants. Most of the refineries in India are planning to set up new desalination plants. In July 2022, VA Tech Wabag, a Chennai-based pure-play water technology company, secured a Rs 4.3 billion work order from Reliance Industries Limited for a 53 mld desalination plant at its refinery in Jamnagar, Gujarat. The en­gineering, procurement and construction (EPC) contract includes the design, engineering, procurement, supply, construction, erection, pre-commissioning, commissioning and performance guarantee test run of the seawater reverse osmosis (SWRO) plant. The plant will employ state-of-the-art pre-treatment technology in the form of lamella clarification, filtration and ultrafiltration followed by reverse osmosis technologies to convert seawater into pro­ce­ssed water. In another development, in Sep­tem­ber 2022, Mangalore Refineries and Petroche­micals Limited completed a 30 mld desalination plant on its premises.


The desalination sector faced many challenges during the Covid-19 pandemic. These included shortage of manpower, raw materials and eq­uipment, and liquidity issues. Construction activities were stopped, as a result of which the short- and medium-term targets for constructing de­salination plants were impacted. This also aff­ected long-term targets of the government as well as industries. However, the desalination se­c­tor, like many other sectors, has sta­r­ted recovering. New desalination plants are be­ing set up by industries for captive consumption.

Another major challenge is the cost of de­salination plants. According to the Desalination Association of India, the production cost of a brackish water desalination plant is Rs 10 per cum to Rs 15 per cum, while that of a desalination plant varies from Rs 40 per cum to 50 per cum. On an average, the cost of converting seawater into desalinated water is about 10 paisa per litre of water produced. However, the cost of fresh water supplied through pipes is under 0.80 paisa a litre. Therefore, desalinated water is per costly proposition, even for industrial use.

Another aspect that adds to the cost of desalinated water is the cost of imported membranes for RO plants. Membranes used in RO plants are expensive and are mostly imported from the US or China. The cost of importing adds to the taxes and duties, making membranes ex­pensive, and also increases the cost of producing desalinated water. Membrane biofouling is another issue faced in RO plants. The membra­n­es used in these plants require continuous cleaning or regular replacement due to biofouling. To overcome this, chlorination is the most commonly used disinfection process. However, it has several disadvantages such as formation of disinfected by-products and being ineffective against some types of microbes.

Another challenge faced by industrial desalination plants is the improper selection of cont­rac­tors resulting in inefficiencies in terms of capabilities of pretreatment processes and core RO designs. This results in irreversible fouling and scaling of SWRO membranes. Also, there is lack of expertise for taking up technical studies before executing the project on a large scale.

Future outlook

The country’s desalination industry is anticipated to be driven by the increased demand for water from various industries and government support. According to India Infrastruc­ture Resear­ch, over 700 mld of industrial de­sali­nation ca­pa­city is expected to come up. Of this, around 370 mld is expected to be added in Gujarat, followed by Andhra Pradesh (194 mld), Tamil Na­du (102 mld), Karnataka (30 mld), Odisha (20 mld) and Maharashtra (10 mld). For this, around Rs 50 billion worth of in­vestment is anticipated to be required. In ter­ms of technology, RO-based plants of over 17 mld SWRO-based plants of 10 mld and other technology-based plants (such as membrane technology and hybrid technology) of around 10 mld are anticipated to be set up.

Given the country’s rapidly growing economy, coupled with a burgeoning population and stricter regulations against groundwater ex­trac­tion, it is evident that desalination is the answer to our water needs not only for drinking purposes but also for the sustenance of the industrial sector. Going forward, the Indian industrial desa­lination market is expected to grow rapidly.