The use of water is rising faster than the global population. The factors mainly responsible for its rise in use are population growth, development and climate change. According to the World Resources Institute, water use has been growing at more than twice the rate of population increase in the last century. There’s enough water on earth, but the problem is that only 2.5 per cent of it is fresh, out of which two-third is snow and ice. There is enough water, but that is not enough for the world. According to experts, only 8 per cent of the planet’s fresh water supply goes to domestic use and about 70 per cent is used for irrigation and 22 per cent in industry. Over a billion people lack access to clean drinking water, and over two billion live without adequate sanitation, leading to deaths of five million people, mostly children, each year from preventable waterborne diseases. We need to urgently deal with water risks — droughts and insufficient rainfall, floods and contamination. We need integrated water resource management that takes into account who needs what kind of water, as well as where and how to use it most efficiently.
You shouldn’t be surprised if you are told that the lack of clean water causes more deaths in the world than war. The problem is that there is enough water, but it is not available where it should be. Some regions of the world have too much of it, whereas some other regions suffer from perpetual shortages. In some regions, water supplies are contaminated not only by the discharged toxic contaminants, but also by arsenic and other naturally occurring poisonous pollutants found in groundwater aquifers. One of the UN millennium development goals is to cut the proportion of people without access to clean water by the first half by 2015. Even if this goal is fulfilled, the sad thing is that millions of people will still die because of contaminated water. In the developing world, roughly two million people die every year due to diarrhoea -- 90 per cent of them being small children. According to an estimate, between 34 million and 76 million people could perish because of contaminated water or water-related diseases by 2020, even if the UN millennium development goals are met. Rainwater harvesting, equitable water distribution and prevention of pollution through proper sanitation are some known methods for water conservation.
Water is needed for personal use, agriculture and industry. To meet the current needs and enhancement demands, we need sophisticated social and engineering solutions. One way is to divert the flow of water from plentiful to scarce regions. This, however, has certain limitations. One of the most important limitation is that no one wants to think that he has more than what is required by him. Diversion often leads to political uncertainty, particularly if it relates to something as important as water. One of the strategies suggested for reducing water use in agriculture is drip irrigation technology (an irrigation method that saves water and fertiliser by allowing water to drip slowly to the roots of plants, either onto the soil surface or directly onto the root zone, through a network of valves, pipes, tubing, and emitters. It is done through narrow tubes that deliver water directly to the base of the plant). Water loss in urban supply systems is also a significant problem.
Desalination is one of the methods adopted by many countries to meet their water needs. There are more than 15,000 desalination plants around the world providing fresh water from salt and brackish water. This number is growing. One must, however, recognise that desalination plants are expensive to build and require a lot of energy to operate. Thus, the technology needs improvement, both in terms of cost effectiveness and energy efficiency. What we need is cost-effective desalination technologies. For example, nanotubes of carbon have shown excellent salt filtering abilities. We need more innovative technologies to make water affordable. The technologies that are being developed include improved recycling of wastewater and sewage treatment so that water can be used for non-personal uses such as irrigation or industrial purposes. The application of these technologies needs utmost precaution to safeguard the quality of recycled water.
The barriers for implementing water treatment technologies include high capital and operation and maintenance (O&M) costs. We need appropriate water treatment technologies that need minimal pre-treatment and much reduced power requirements. We need technologies that can use local materials and minimal skills for operation and maintenance.
Waterborne infectious diseases are major health risks. Microbial risk assessment (MRA) addresses questions like which water treatment option is best for preventing illness and death, what are the most dangerous pathogens found in water, how did they get there, how do we set standards for water quality, who are the most sensitive members of the population, how can we protect them and what should we do for the optimal utilisation of the resources to prevent waterborne diseases. MRA is an evolving procedure. MRA allows evaluation of even delayed risks. There are still gaps in the understanding of human exposure to pathogens in water. Many questions are still unresolved. Interpretations of analytical methods for specific pathogens or “marker” pathogens are necessary to provide a robust capability in this area. Researchers are working on the development of rapid, inexpensive and easy to use methods to resolve clean water crisis.
Water — one of the five elements, three-fourth of the planet, two-third of us, an ordered crystalline arrangement and a jumble of disordered molecules, a transparent, tasteless, and colourless thing, the oil of the 21st century — is too precious for us. The wonder has given us the wake up call — save me in order to save yourself. zz
(The writer is a biotechnologist and ED, Birla Institute of Scientific Research, Jaipur)