Water is a vibrant resource and is available in abundance as covering seven-tenth of the earth’s surface. The availability of water is dependent on factors like season, temperature, and location and other similar governing factors. However, factors like climate change have led to many incidents of droughts and thus regions are looking for alternative water resources. Some of these regions were the ones that previously had water supply in abundance.
With the population of the world continuously growing, the need of water is set to grow and hence the growing efforts to enhance the efficacy of water. Due to the declining supplies of freshwater, the quest for substitute supplies of water resulted to the concept of seawater desalination. Technological advancements from the last two years have made desalination an economically viable proposition. With the help of extensive use of technology with their own challenges of the environment.
Utilization of ocean water in an emergency situation is an important opportunity for people living in an island or coastal areas. Natural disasters are having the potential to interfere in supply fresh water in these regions. Though drinking of ocean water is an ideal option for individuals due to its harmful effect on kidneys. As kidneys process salt, they have the potential of producing urine that is containing less salt as compared to ocean water. This proves it needs more water than which is present in ocean water to free the body of extensive salt. As a person drinks ocean water, that he/shebecomes progressively dehydrated, instead of being rehydrated making the desalinating ocean water the attractive option.
Desalting or desalination is the procedure of eliminating salt from ocean water to generate fresh water. Desalinated water can be used for drinking water, or for industrial or agriculture use. Desalination is integrally an energy-intensive process. There is a motive why wells are drilled, conservation efforts are tired before agencies, authorities and governments using desalination and treatment plants used for desalination. In various situations, ocean water must be filtered/ treated before the desalination process takes place. This process involves a lot like consuming a great deal of energy, it needs manpower, facilities and equipment. Thus making the resultant output water an expensive water.
Despite the cost, eliminating salt from ocean water is a valuable process that is used in several areas. Luxurious water is better than no water and the technology developments, sources of renewable energy like solar power or wind make desalination more workable and cost-effective.
There are various ways that this process takes place. The most common are reverse osmosis and distillation.
- Reverse osmosis: The reverse osmosis process uses pressure and the semi-permeable membrane to achieve desalinated water. Osmosis is the naturally occurring process wherein a solution and a solvent balance amongst the semi-permeable membrane. Reverse osmosis happens as solvent flows from less concentrated to more concentrated water unless the steadiness is accomplished. In reverse osmosis, a pressure is applied to the salt water side forcing water molecules to move towards less intense side, producing clean and salt-free water.
- Distillation: Procedure of boiling the ocean water and accumulating the condensate that has left salt and minerals behind.
Nowadays, desalination plants are having an environmental impression. Primarily, desalination plants use lots of energy. If the energy is coming from the sources of fossil fuel, there is the issue of emissions of greenhouse gas and air. These issues can be controlled by the use of renewable energy. Secondarily, the challenge is the intake of water. Intakes of the screened surface are cost-effective, although intakes of subsurface are superior. With the intake of the subsurface, seawater is drained in with the help of pierced pipes under the floor of the sea where the deposits of mud and sand behave like a mesh to shade out many of the organisms. Intakes of the surface are dangerous as they can attract in fish eggs and other beneficial organisms that slide through screens. The third trial is a discharge of brine that is two times as salty as seawater driven in the desalination plant. The large salinity of brine may have harmful effect on the marine life. The best way to ease the difficulty is brine dilution with wastewater in advance discharge in the sea.
An acknowledged global leader in desalination is Israel, taking the quantum leap forward as Moses first attempt to solve the major issue of drinking water by arresting a rock with staff. Israel is also playing a major role in recycling water. They use treated municipal wastewater for agriculture irrigation rather than freshwater. Israel has discovered other ways in conserving water. Drip irrigation has substituted incompetent spray irrigation. In the year 1965, Israel’s Netafim Company has started the drip irrigation technology. In several years, it transformed the world of agricultural irrigation. Netafim functions from over 37 subsidiaries in around 150 regions with about 13 factories across the globe. Recently the novel innovators are entering the desalination project. Israel’s IDE Technologies is one and was used in constructing the San Diego plant. Amongst the engineering companies, France’s Veolia Environment is the leader, following Power & Water division of US conglomerate General Electric and South Korea’s Doosan.
At the price of more than USD 1 Bn, San Diego County is establishing the desalination plant in Carlsbad that supplies over 200 Mn liters per day (MLD) to the country. In Israel, various desalination plants are providing over 1360 MLD of potable water and the plants are built and are projected to increase to greater than 2,080 MLD in the coming years.