What is Desalination

Desalination is the process of removing excess salt and other minerals from water to render it fit for human consumption. The need for Desalination is gaining importance because fresh water is scarce. There is bound to be a water crisis not only in India but also over several countries in the world. Around 22.5 crore people in India do not have access to safe drinking water. Requirement of freshwater in India for domestic consumption, agriculture, and industrial purposes every year is close to 900 billion cu m. With the growth of world population the need of fresh water has also increased substantially which has resulted in growth of desalination installation as well. Logically the desalination activities are concentrated on those parts of the earth where availability of water is scares. This is precisely the reason why more than 80% of desalination plants are located in the water scares Middle East region. Unequal water distribution also exists within our country and fresh water desalination technology is getting concentrated more on water scares areas such as Gujarat, Tamil Nadu and Rajasthan. Desalination can be a perfect solution for these water problems. India started its first desalination project at Andaman way back in 1946 & has so far installed 175 plants.

Deslation Method and Technology

There are Two basic technologies are used in the desalination plants. They are either thermal based or membrane based. There is no “best” method of desalination. Generally, distillation and RO are used for sea water desalting, while RO and electrodialysis are used to desalt brackish water. However, the selection of a process should be dependent on a careful study of site conditions and the application at hand. Membrane-based technologies include reverse osmosis (RO) and electro-dialysis (ED), while thermal-based technologies include multistage flash evaporation (MSE), multi-effect distillation (MED), multi-stage flash distillation (MSF), and vapor compression (VC). Both the technologies have proved to be quite popular. RO produces drinking water by forcing seawater against a semi-permeable membrane, producing pure water on one side and concentrated brine on the other. In contrast, MSF process involves both evaporation and condensation split into several stages, which is repeated many times. Seawater is heated and evaporated, and the steam is condensed to produce desalinated water in this process. The benefit of MSF is that it can produce large amounts of water at a time.

Global scenario

Desalination facilities exist in about 120 countries around the world. According to the International Desalination Association (IDA), the global desalination market is expected to grow to US$ 95 billion through 2005 to 2015. According to a report by Global Water Intelligence (GWI), the worldwide desalination industry is expected to grow 140 percent over the next decade, with US$ 25 billion in capital investment by 2010 and US$ 56 billion by 2015. While countries like the US, Spain, and the Gulf countries have been able to build mega plants, other countries in Asia, Africa, and South America have inadequate resources to do so. Initiatives have been taken by the governments in Spain, the Middle East, and Australia to construct desalination plants to turn seawater into drinking water.

India Desalination Companies

Note most of the Desalination Companies are involved in Water Treatment in India as well.Indian desalination Association (InDA), an affiliate of International Desalination Association was set up in 1991 in Chennai, with goal for the development and promotion of the appropriate use of desalination and desalination technologies nation wide in water supply, water reuse, water pollution control, water purification, water treatment, other water sciences and technologies and various solute-solvent separations. Some of the companies in India are:

1. Bhabha Atomic Research Centre (BARC) set up a 1.8 million-liters-a-day capacity desalination plant at Kalpakkam in Tamil Nadu in 2008 and is set to comission a MSF-based plant there itself. BARC has set up several desalination plants in rural Rajasthan, Andhra Pradesh and Gujarat, producing 30,000 L a day. It has licensed its technology to as many as seven industries. IVRCL, IL&FS, Mahindra and Reliance are other companies that have set up desalination plants. Foreign players like Israel Desalination Enterprises Technologies (IDE) and GE are also setting up such plants in India.
2. Larsen & Toubro – takes the total water management of an industrial or municipal unit into account and provides integrated solutions involving both water and wastewater treatment with desalination and recycling needs and aims to provide end to end solutions. L&T has established as a leading player in the water sector over the last 20 years. The company is focused on conventional water and waste water treatment technologies and systems like municipal water supply, effluent treatment, sewage treatment and pre-treatment of water for industries. The track record includes some of the most prestigious projects in India and abroad for various, urban, municipal & rural and industrial clients. L&T’s Water Process Technology Business Unit, based at Vadodara is   expanding its technical expertise and process capability to address the demand of high-end water technologies and markets.  The thrust is on providing knowledge-based water solutions, such as Desalination of water (sea water, brackish water, normal water) utilizing technologies like membrane processes – reverse osmosis, ultra-filtration, thermal processes – MSF, MED and VC and advanced technologies like nano filtration, eletrodialysis, etc.
3. VA Tech Wabag – has over 20 years of experience in this sector  is one of the world’s few companies to possess a complete range of technologies for the desalination of sea and brackish water. Indeed, WABAG is able to offer optimised, tailor-made solutions for both the production of drinking water and industrial desalination with technologies such as:Reverse osmosis,Thermal desalination, Multi-effect distillation, Mechanical vapour compression, Thermal vapour compression ,Multi-stage flash ElectrodialysisIon exchange.WABAG has designed, installed and successfully commissioned over 100 plants worldwide.
4. Thermax Ltd. – Thermax’s Water & Waste Solutions business offers green solutions in the field of water and wastewater treatment and recycling for industrial, commercial, defense, hospitality and municipal sectors. Clients are provided total water management and Zero Liquid Discharge (ZLD) solutions that include water, waste water treatment & recycling. Thermax designs sea water reverse osmosis for effective and efficient desalination. the company has a number of successful installations that also incorporate energy recovery systems improve the returns from the system. Thermax has supplied one of the largest seawater desalination plant to a leading chemical manufacturer.
5. Kirloskar Brothers Ltd. – is India’s largest manufacturer and exporter of pumps and also the largest infrastructure pumping project contractor in Asia. KBL has created the world’s largest pumping scheme which irrigates more than two million hectares of land. KBL is one of the three manufacturers in the world who have manufactured and installed 200 kW Canned motor pumps for nuclear application . The company offers Total Fluid Handling Solutions for applications in verticals like Water and Waste Water Management, Total Water and Waste water Treatment Plants.
6. Aquatech Systems Asia Pvt. Ltd. –  the Industrial Services Division offers clients a wide variety of value added services that range from spare parts supply to water by the gallon. Aquatech Industrial Services is focused on helping plant personnel get the most out of their water treatment system. Aquatech has over 25 years of experience designing and supplying a full range of industrial water treatment systems. Today, seawater is becoming a growing source of water supply as others are diminishing.