Water is deemed as one of the most essential element to human life, even more so than food.
The human body can last for weeks without food but it cannot last more than three days without water.
In many ways water contributes immensely to sustainable development, yet this invaluable natural resource is being continuously abused and depleted.
Mismanagement and human greed have resulted in severe water shortages and polluted water, giving rise to water crises around the globe.
In 1992, a proposal for an international day to recognise the importance of freshwater was made at the United Nations Conference on Environment and Development (UNCED).
WATER SITUATION
According to United Nations Environment Programme (UNEP), the total volume of water on Earth is about 1.4 billion km3 (cubic kilometers). The volume of freshwater resources is around 35 million km3, or about 2.5 per cent of the total volume.
Out of these freshwater resources, about 24 million km3 or 70 per cent is in the form of ice and permanent snow cover in mountainous regions, the Antarctic and Arctic regions.
Around 30 per cent of the world's freshwater is stored underground in the form of groundwater (shallow and deep groundwater basins up to 2,000 metres, soil moisture, swamp water and permafrost).
This constitutes about 97 per cent of all the freshwater that is potentially available for human consumption.
According to UNEP, freshwater lakes and rivers hold an estimated 105,000 km3 or around 0.3 per cent of the world's freshwater.
The total usable freshwater supply for ecosystems and humankind is about 200,000 km3 of water, which is less than 1 per cent of all freshwater resources.
GLOBAL WATER CRISIS
According to FAO, by 2025 almost 1.8 billion people will be living in countries or regions with absolute water scarcity, and two-thirds of the world population could be under stress conditions.
Based on World Water Assessment Programme (WWAP), each person needs 20-50 litres of safe freshwater a day to ensure their basic needs for drinking, cooking and cleaning.
Nevertheless, according to World Health Organisation (WHO) more than one in six people worldwide (about 894 million) do not have access to this amount of safe freshwater.
Globally, diarrhoea is the leading cause of illness and death, and 88 per cent of diarrhoeal deaths are due to a lack of access to sanitation facilities, together with inadequate availability of water for personal hygiene and drinking.
Today 2.5 billion people, including almost one billion children, live without even basic sanitation. Every 20 seconds, a child dies as a result of poor sanitation. That is 1.5 million preventable deaths each year.
The statistics above come from the Water Supply and Sanitation Collaborative Council (WSSCC), an international organisation with its secretariat based in Geneva, Switzerland.
STILL MORE PROBLEMS
According to WSSCC, in Sub-Saharan Africa, treating diarrhoea takes 12 per cent of the health budget. On a typical day, patients suffering from faecal-related disease occupy more than half the hospital beds.
In a study done by WWAP, two million tonnes of human waste is disposed into water courses daily. In developing countries, 70 per cent of industrial wastes are dumped untreated into waters where they pollute the usable water supply.
This fact collaborated GEO-4's findings, which states projected increases in fertiliser use for food production and in wastewater effluents over the next three decades suggest there will be a 10-20 per cent global increase in river nitrogen flows to coastal ecosystems.
WWAP also said half of the world's wetlands have been lost since 1900.
Between 1991 and 2000 over 665,000 people died in 2,557 natural disasters of which 90per cent were water-related events.
IMPACT OF CRISIS
The daily drinking water requirement per person is between 2 and 4 litres, but it takes 2,000 to 5,000 litres of water to produce one person's daily food.
According to FAO, it takes 1,000-3 000 litres of water to produce just one kilo of rice and 13,000 to 15,000 litres to produce one kilo of grain-fed beef.
Over the period to 2050, FAO said the world's water have to support the agricultural systems that would feed and create livelihoods for an additional 2.7 billion people.
In terms of the extent of land under irrigation globally, FAO estimates it to be around 277 million hectares or about 20 per cent of all cropland. Rain fed agriculture is practiced on the remaining 80 per cent of the arable land.
The Inter-governmental Panel on Climate Change predicts yields from rain-dependent agriculture could be down by 50 per cent by 2020.
Due to climate change, the UN's agency said Himalayan snow and ice, which provide vast amounts of water for agriculture in Asia could decline by 20 per cent by 2030.
It said irrigation increases yields of most crops by 100 to 400 per cent, and irrigated agriculture currently contributes to 40 per cent of the world's food production.
However, poor drainage and irrigation practices have led to waterlogging and salinisation of approximately 10 per cent of the world's irrigated lands.
AN AMBITIOUS DISCOVERY
Scientists have found a way to make smaller portable desalination machines, which could be ``immensely'' useful in countries with scarce water resources, or for decontaminating wells in disaster-struck regions.
The new technique, suggested by researchers from the Massachusetts Institute of Technology (MIT) and Pohang University of Science and Technology (POSTECH), is based on the use of tiny, four-by-five-millimeter devices designed to exploit the electrochemical transport phenomenon, ``ion concentration polarization.''
It would take from 1,000 to 10,000 of these devices to make a single desalination machine, which would be comparable in size to a conventional desktop computer.
Such machines would obviously be useful in the earthquake-rattled Chile and Haiti, where the shortage in drinking water has been a problem, the researchers said.
The study was published by Nature Nanotechnology, a peer-review journal.
``A device produced through the technology of our findings would produce a smaller amount of fresh water compared to existing equipment, but would be small enough to carry around, making them effective for relief efforts in disaster areas or for military use,'' said POSTECH's Kwang Kwan-hyoung, who participated in the research led by MIT's Kim Sung-jae and Han Jong-yoon.
``The hydrogen ion concentration level of the water produced by these devices range between 7 and 7.5 pH, with salt concentration of around 3 mm, thus qualifying as potable water by World Health Organization (WHO) standards. The method also allows for the removal of micro particles and pathogens.''
The shortage of fresh water is a critical global challenge, a situation made more severe by population growth and increased industrial and agricultural activities, and this has scientists around the world devoting themselves to developing more effective technologies to convert seawater into fresh water.
The current standard approaches to seawater desalination are reverse osmosis, which employs high-pressure pumps to force brine from water brine through a membrane impermeable to salt, and electro-dialysis, a process that uses electricity to draw salt ions out of water through a membrane.
Although these methods are relatively energy efficient in terms of freshwater conversion, they both require large plant-scale operations and significant amounts of power consumption, while the removal of bacteria and other pathogens presents another challenge.
Therefore, researchers have been focusing on developing portable, low-power desalination systems, which would be useful for government and military use in disaster-stricken areas or resource-limited settings. And the Korean researchers claim they have the best solution for now.
Ion concentration polarization, also called as ion depletion or enrichment, occurs when a current is passed through ion-selective membranes, and the Nature Nanotechnology paper suggests a mechanism to use this phenomenon to isolate desalinated water from seawater streams.
The desalinated and ``concentrated'' streams are divided and flow into different channels ― the process is also designed to push salt and other large particles away from the membrane, which eliminates the possibility of membrane fouling, a frequent problem in reverse osmosis and electro-dialysis plants.
The human body can last for weeks without food but it cannot last more than three days without water.
In many ways water contributes immensely to sustainable development, yet this invaluable natural resource is being continuously abused and depleted.
Mismanagement and human greed have resulted in severe water shortages and polluted water, giving rise to water crises around the globe.
In 1992, a proposal for an international day to recognise the importance of freshwater was made at the United Nations Conference on Environment and Development (UNCED).
WATER SITUATION
According to United Nations Environment Programme (UNEP), the total volume of water on Earth is about 1.4 billion km3 (cubic kilometers). The volume of freshwater resources is around 35 million km3, or about 2.5 per cent of the total volume.
Out of these freshwater resources, about 24 million km3 or 70 per cent is in the form of ice and permanent snow cover in mountainous regions, the Antarctic and Arctic regions.
Around 30 per cent of the world's freshwater is stored underground in the form of groundwater (shallow and deep groundwater basins up to 2,000 metres, soil moisture, swamp water and permafrost).
This constitutes about 97 per cent of all the freshwater that is potentially available for human consumption.
According to UNEP, freshwater lakes and rivers hold an estimated 105,000 km3 or around 0.3 per cent of the world's freshwater.
The total usable freshwater supply for ecosystems and humankind is about 200,000 km3 of water, which is less than 1 per cent of all freshwater resources.
GLOBAL WATER CRISIS
According to FAO, by 2025 almost 1.8 billion people will be living in countries or regions with absolute water scarcity, and two-thirds of the world population could be under stress conditions.
Based on World Water Assessment Programme (WWAP), each person needs 20-50 litres of safe freshwater a day to ensure their basic needs for drinking, cooking and cleaning.
Nevertheless, according to World Health Organisation (WHO) more than one in six people worldwide (about 894 million) do not have access to this amount of safe freshwater.
Globally, diarrhoea is the leading cause of illness and death, and 88 per cent of diarrhoeal deaths are due to a lack of access to sanitation facilities, together with inadequate availability of water for personal hygiene and drinking.
Today 2.5 billion people, including almost one billion children, live without even basic sanitation. Every 20 seconds, a child dies as a result of poor sanitation. That is 1.5 million preventable deaths each year.
The statistics above come from the Water Supply and Sanitation Collaborative Council (WSSCC), an international organisation with its secretariat based in Geneva, Switzerland.
STILL MORE PROBLEMS
According to WSSCC, in Sub-Saharan Africa, treating diarrhoea takes 12 per cent of the health budget. On a typical day, patients suffering from faecal-related disease occupy more than half the hospital beds.
In a study done by WWAP, two million tonnes of human waste is disposed into water courses daily. In developing countries, 70 per cent of industrial wastes are dumped untreated into waters where they pollute the usable water supply.
This fact collaborated GEO-4's findings, which states projected increases in fertiliser use for food production and in wastewater effluents over the next three decades suggest there will be a 10-20 per cent global increase in river nitrogen flows to coastal ecosystems.
WWAP also said half of the world's wetlands have been lost since 1900.
Between 1991 and 2000 over 665,000 people died in 2,557 natural disasters of which 90per cent were water-related events.
IMPACT OF CRISIS
The daily drinking water requirement per person is between 2 and 4 litres, but it takes 2,000 to 5,000 litres of water to produce one person's daily food.
According to FAO, it takes 1,000-3 000 litres of water to produce just one kilo of rice and 13,000 to 15,000 litres to produce one kilo of grain-fed beef.
Over the period to 2050, FAO said the world's water have to support the agricultural systems that would feed and create livelihoods for an additional 2.7 billion people.
In terms of the extent of land under irrigation globally, FAO estimates it to be around 277 million hectares or about 20 per cent of all cropland. Rain fed agriculture is practiced on the remaining 80 per cent of the arable land.
The Inter-governmental Panel on Climate Change predicts yields from rain-dependent agriculture could be down by 50 per cent by 2020.
Due to climate change, the UN's agency said Himalayan snow and ice, which provide vast amounts of water for agriculture in Asia could decline by 20 per cent by 2030.
It said irrigation increases yields of most crops by 100 to 400 per cent, and irrigated agriculture currently contributes to 40 per cent of the world's food production.
However, poor drainage and irrigation practices have led to waterlogging and salinisation of approximately 10 per cent of the world's irrigated lands.
AN AMBITIOUS DISCOVERY
Scientists have found a way to make smaller portable desalination machines, which could be ``immensely'' useful in countries with scarce water resources, or for decontaminating wells in disaster-struck regions.
The new technique, suggested by researchers from the Massachusetts Institute of Technology (MIT) and Pohang University of Science and Technology (POSTECH), is based on the use of tiny, four-by-five-millimeter devices designed to exploit the electrochemical transport phenomenon, ``ion concentration polarization.''
It would take from 1,000 to 10,000 of these devices to make a single desalination machine, which would be comparable in size to a conventional desktop computer.
Such machines would obviously be useful in the earthquake-rattled Chile and Haiti, where the shortage in drinking water has been a problem, the researchers said.
The study was published by Nature Nanotechnology, a peer-review journal.
``A device produced through the technology of our findings would produce a smaller amount of fresh water compared to existing equipment, but would be small enough to carry around, making them effective for relief efforts in disaster areas or for military use,'' said POSTECH's Kwang Kwan-hyoung, who participated in the research led by MIT's Kim Sung-jae and Han Jong-yoon.
``The hydrogen ion concentration level of the water produced by these devices range between 7 and 7.5 pH, with salt concentration of around 3 mm, thus qualifying as potable water by World Health Organization (WHO) standards. The method also allows for the removal of micro particles and pathogens.''
The shortage of fresh water is a critical global challenge, a situation made more severe by population growth and increased industrial and agricultural activities, and this has scientists around the world devoting themselves to developing more effective technologies to convert seawater into fresh water.
The current standard approaches to seawater desalination are reverse osmosis, which employs high-pressure pumps to force brine from water brine through a membrane impermeable to salt, and electro-dialysis, a process that uses electricity to draw salt ions out of water through a membrane.
Although these methods are relatively energy efficient in terms of freshwater conversion, they both require large plant-scale operations and significant amounts of power consumption, while the removal of bacteria and other pathogens presents another challenge.
Therefore, researchers have been focusing on developing portable, low-power desalination systems, which would be useful for government and military use in disaster-stricken areas or resource-limited settings. And the Korean researchers claim they have the best solution for now.
Ion concentration polarization, also called as ion depletion or enrichment, occurs when a current is passed through ion-selective membranes, and the Nature Nanotechnology paper suggests a mechanism to use this phenomenon to isolate desalinated water from seawater streams.
The desalinated and ``concentrated'' streams are divided and flow into different channels ― the process is also designed to push salt and other large particles away from the membrane, which eliminates the possibility of membrane fouling, a frequent problem in reverse osmosis and electro-dialysis plants.
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