Low-cost remedies to remove arsenic
http://www.hinduonnet.com/thehindu/thscrip/print.pl?file=2004060200151100.htm&date=2004/06/02/&prd=bl&
A STAINLESS steel filter device has been found effective in the removal of arsenic from contaminated drinking water and in making it safe for human consumption.
Interestingly, the filter medium itself is a processed waste material from the steel industry. The device is easy to operate and affordable, even for use in households, according to researchers at the Naval Materials Research Laboratory (NMRL), Ambernath, Maharastra.
Six prototypes of the arsenic removal filter have been put through field trials in the arsenic-affected villages of West Bengal for more than six months.
NMRL, a laboratory under the Defence Research and Development Organisation (DRDO), has filed for a national patent for the process and an international patent (US) for the product (filter).
The main investment (one-time) in the novel device is around Rs 500 for the stainless steel filter and Rs 150for the plastic parts.
The cost of removing arsenic from the contaminated waters works out to Rs 27-30 per 1,000 litres of water.
The life of the filter is five years and it requires little maintenance — just the normal washing and replacement of active ingredients. It does not require power (electricity or battery) and is easy to operate and maintain.
The wastes generated can be converted into cement bricks that can be used for construction, say the NMRL scientists.
Explaining the use of the device, Dr Narayan Das, Director, and Ms Kshipra Misra, Scientist, NMRL, said the filter works on the principle of co-precipitation and adsorption, which is followed by filtration through treated sand. The medium used in the filter is a processed waste of the steel industry and is easily available.
The device has three containers. The reactant material is placed in the first, and the sand-bag in the second.
The water contaminated with arsenic is allowed to flow into the first container, through the second and through the cloth filters. The water thus filtered is collected in the bottom-most container.
The reactant material and sand are periodically replaced, according to the usage.
There are several waste-water treatment technologies and kits for removal of arsenic available in the market.
Their high cost, problems of waste disposal and effect on the environment have been major limitations to their acceptability, said the scientists from the Marine Biology and Environmental Sciences Division of NMRL.
Interestingly, the device was judged one of the most innovative technologies and, recently, NMRL has successfully transferred the technology to the Indian Institute of Management, Ahmedabad (IIMA). The technology has been given on a non-exclusive basis, Ms Misra said.
The next phase of the development involves the fabrication of community type filter devices that can be used in hospitals and schools, and to meet the safe drinking water demands of larger communities.
For this, NMRL has entrusted the job to the Indian Institute of Technology, Mumbai (IIT). A one-year project for the development of prototypes has been finalised, Ms Misra said.
An alarming 66 million people in the Indo-Gangetic belt and around 55 million people in neighbouring Bangladesh are exposed to the threat of arsenic poisoning as the water sources are contaminated.
The levels of arsenic found in drinking water range from 50 ppb (parts per billion) to 20 ppm (parts per million) in parts of Bihar, West Bengal and Chattisgarh States, as against 10 ppb stipulated by the WHO.
The problem of arsenic in groundwater is not unique to India. Reports of arsenic poisoning have emerged from China, Taiwan, Mongolia, Argentina, Chile, Mexico, Vietnam and even the UK, though the levels are far lower.
What happens if people drink arsenic contaminated water for long periods? The known health effects are skin cancer, bronchitis, conjunctivitis and cirrhosis.
NMRL scientists have installed arsenic removal filters in Kamdevkati and Chatra villages of 24 Paraganas District, one of the worst affected in West Bengal, and have run trials in association with `Save the Environment', an NGO and the AIIHPH (All-India Institute of Hygiene and Public Health) in September 2003.
The arsenic and iron concentration fell well below the WHO/EPA drinking water standards of less than 10 ppb and less than 300 ppb respectively.
The filtered water quality is being monitored by the NMRL team and the AIIHPH.
The Jadhavpur University has done an extensive study of the prevalence of arsenic pollution in groundwater in West Bengal and the State Government has also initiated steps to control this growing menace.
The Hyderabad-based National Geophysical Research Institute (NGRI), has also done studies to get to the source of the problem.
Four foreign funding agencies have also joined hands with the environmental engineering cell of Bengal Engineering College to install 85 arsenic-removing units in three districts of West Bengal.
They are: Water For People (a non-governmental organisation based in North America), Rotary Club of Puerto Rico, US-based Conrad N. Hilton Foundation and Das Foundation.
Bengal Engineering College, a deemed university, has installed 10 such units in 24 North Parganas.
The university has an arsenic removal unit, a device that uses activated alumina and is attached to the hand-pumped tubewells.
The alumina absorbs the arsenic and raw iron present in the water. One unit can treat 6,000 litres of water per day.
There is an ongoing Indo-Australian initiative to examine the steps being taken to eliminate arsenic and recommend cost-effective and ecologically sustainable approaches.
The Murdoch University of Australia and the Regional Research Laboratory (RRL), Bhubaneshwar are the lead organisations in this project.
The Australian Agency for International Development (AusAID) has extended support of Rs 2.7 crore. The AusAID also supports a major project in Bangladesh, where arsenic pollution is severe.
While in the short term there is an urgent need to provide immediate relief to those suffering from the ill-effects of drinking water contaminated by arsenic, the long-term solution has to be based on an scientific assessment of the reasons, sources and geographical spread of the problem and in choosing technologies that are effective and affordable, suggest the NMRL scientists.
Tuesday, January 16, 2007
(WATER TREATMENT INDIA ) Low-cost remedies to remove arsenic
Environmental Entrepreneur,Green Biz.NRN Murthy of Infosys says that we Indians are weak in execution.We need to realize the need and practice of gud project management. Form a group of competent Managers,Give them responsibilities and review the project from day One.
(WATER TREATMENT INDIA) ARSENIC -Nano-solution to a mega-problem
Nano-solution to a mega-problem
http://www.hindu.com/seta/2007/01/11/stories/2007011100081500.htm
BANGLADESH HAS been battling with a silent public health disaster for the past thirty years. The culprits are the deadly arsenic compounds present in the country's tube-well water.
Earlier to the 1970s, health authorities there found an epidemic of gastrointestinal diseases, due to the contamination of surface water from the lakes and rivers by disease-carrying microbes.
Well-intentioned move
In a well-intentioned move, they embarked on a programme, in collaboration with UNICEF and private parties, of digging tube-wells, so as to provide safe drinking water. By the end of 1997, over 80 per cent of its population had access to tube-well water.
Alas, tube-well water is not safe either. It contains arsenic salts at levels far higher than permissible. The problem is not a directly man-made one. Silt from rivers upstream has been, over the centuries, collecting and depositing arsenic in subterranean layers.
A silent killer
Tube-well water arsenic contamination is thus not restricted to Bangladesh alone, but is also seen in Bihar and Eastern UP, but it is Bangladesh that has been hit so calamitously.
Arsenic is a silent killer. It causes skin lesions, affects the stomach, liver, lung, kidney, and blood, disabling them over time. It combines with proteins and enzymes, inactivating them and thus causing slow metabolic disorders.
Past examples
At the extreme, it causes cancers. History is replete with examples of arsenic-induced poisoning and death. Two Popes and even Napoleon Bonaparte are thought to have been murdered through arsenic poisoning. But the scale in Bangladesh is massive, over 40 million of its 130 million are affected. The first case was detected in 1983 by Dr. K. C. Saha of the dermatology department of the Calcutta School of Tropical Medicine. Since then, thousands of cases have been reported.
Professor Dipankar Chakraborty of Jadavpur University, Kolkata, has written about the problem in detail in the Indian Journal of Medical Research, Nature and other journals.
Some methods have been suggested and used to help clear the body of ingested arsenic and prevent skin lesions. Selenium intake appears to remove some arsenic.
Some have suggested that iron sulphate be used in order to help flush arsenic out of the system. Others have suggested that the amino acid methionine may help in reducing the lesion.
How does one plan to remove the offending arsenic from water? Boiling the water to precipitate the arsenic does not work, since it does not come out of solution, as calcium does from hard water.
Nor does boiling convert arsenic into any harmless form, as happens with water contaminated by microbes. What we are looking for is an efficient, inexpensive method.
Applicable for all
The method should be applicable at all scales, from the individual families to the city water supply agencies. A group of researchers from Rice University at Houston, Texas, U.S. has been working for the last several years on precisely this problem.
They have now come out with a workable solution that appears to satisfy many of the above requirements. And their solution, published in the 10 November 2006 issue of Science, makes use of magnetic nanoparticles of iron oxide.
We humans, with our height and girth in metres, are `metre-particles'.
Tiny ants, fruitflies and lice are `millimetre particles' or `milliparticles', while bacteria, which are a thousand-fold smaller, are `microparticles'. Scaling equally down, we reach molecules and atoms whose sizes are in nanometres or even less.
As we reach this nano-scale, the properties of materials change remarkably. Size matters here; it becomes the determinant of the property. Gold glitters as a nugget, as a millimetre speck, and even as a micron particle. Cut it down to the nano scale; it loses the glitter; even its electrical conductivity changes.
New laws
New laws of physics, of the quantum world, begin to operate here. Chemically it is the same, but in various physical properties, nano-gold is quite different from macro-gold.
Even in the nano-dimension, size matters. A 3 nanometre (nm) particle of cadmium selenide shines green, but emits red when its size increases to a bit more than 5 nm. Take the example of magnets. Magnetite, a composite oxide of iron, is a good magnet.
But its magnetic property changes as we cut chunks of it into smaller and smaller pieces. Below 40 nm in size, its magnetic properties actually become more pronounced, and it becomes what physicists call a superparamagnet.
At the same time, as the particle size reduces, the proportion of surface area it exposes also increases. This allows it to `stick' to material more avidly than in the bulk phase.
What the Rice university researchers have done is to exploit this nano-size behaviour of magnetite. They prepared 16-nm size magnetite particles, stirred up a bit of this material in a beaker-full of arsenic-contaminated water.
Large surface area
Two things happened. Magnetite, being an iron-containing material, has an affinity to bind to arsenic salts, and it did so very avidly, thanks to the large surface area it presents at this nm size.
This removed the dissolved arsenic very efficiently from the water. Secondly, they placed an external magnet under the beaker.
This external magnetic field induced the aggregation or clumping of the magnetite into large chunks, which could be decanted or filtered out, leaving arsenic-free water. What does it mean to Bangladesh, and other areas affected by arsenic-contaminated water?
The use of nano-magnetite and a small magnet helps remove the arsenic quickly and efficiently. Here then appears a method worth trying both at the small scale and at the larger community level. Nano-Davids for Mega-Goliaths!
D. BALASUBRAMANIAN
dbala@lvpei.org
http://www.hindu.com/seta/2007/01/11/stories/2007011100081500.htm
BANGLADESH HAS been battling with a silent public health disaster for the past thirty years. The culprits are the deadly arsenic compounds present in the country's tube-well water.
Earlier to the 1970s, health authorities there found an epidemic of gastrointestinal diseases, due to the contamination of surface water from the lakes and rivers by disease-carrying microbes.
Well-intentioned move
In a well-intentioned move, they embarked on a programme, in collaboration with UNICEF and private parties, of digging tube-wells, so as to provide safe drinking water. By the end of 1997, over 80 per cent of its population had access to tube-well water.
Alas, tube-well water is not safe either. It contains arsenic salts at levels far higher than permissible. The problem is not a directly man-made one. Silt from rivers upstream has been, over the centuries, collecting and depositing arsenic in subterranean layers.
A silent killer
Tube-well water arsenic contamination is thus not restricted to Bangladesh alone, but is also seen in Bihar and Eastern UP, but it is Bangladesh that has been hit so calamitously.
Arsenic is a silent killer. It causes skin lesions, affects the stomach, liver, lung, kidney, and blood, disabling them over time. It combines with proteins and enzymes, inactivating them and thus causing slow metabolic disorders.
Past examples
At the extreme, it causes cancers. History is replete with examples of arsenic-induced poisoning and death. Two Popes and even Napoleon Bonaparte are thought to have been murdered through arsenic poisoning. But the scale in Bangladesh is massive, over 40 million of its 130 million are affected. The first case was detected in 1983 by Dr. K. C. Saha of the dermatology department of the Calcutta School of Tropical Medicine. Since then, thousands of cases have been reported.
Professor Dipankar Chakraborty of Jadavpur University, Kolkata, has written about the problem in detail in the Indian Journal of Medical Research, Nature and other journals.
Some methods have been suggested and used to help clear the body of ingested arsenic and prevent skin lesions. Selenium intake appears to remove some arsenic.
Some have suggested that iron sulphate be used in order to help flush arsenic out of the system. Others have suggested that the amino acid methionine may help in reducing the lesion.
How does one plan to remove the offending arsenic from water? Boiling the water to precipitate the arsenic does not work, since it does not come out of solution, as calcium does from hard water.
Nor does boiling convert arsenic into any harmless form, as happens with water contaminated by microbes. What we are looking for is an efficient, inexpensive method.
Applicable for all
The method should be applicable at all scales, from the individual families to the city water supply agencies. A group of researchers from Rice University at Houston, Texas, U.S. has been working for the last several years on precisely this problem.
They have now come out with a workable solution that appears to satisfy many of the above requirements. And their solution, published in the 10 November 2006 issue of Science, makes use of magnetic nanoparticles of iron oxide.
We humans, with our height and girth in metres, are `metre-particles'.
Tiny ants, fruitflies and lice are `millimetre particles' or `milliparticles', while bacteria, which are a thousand-fold smaller, are `microparticles'. Scaling equally down, we reach molecules and atoms whose sizes are in nanometres or even less.
As we reach this nano-scale, the properties of materials change remarkably. Size matters here; it becomes the determinant of the property. Gold glitters as a nugget, as a millimetre speck, and even as a micron particle. Cut it down to the nano scale; it loses the glitter; even its electrical conductivity changes.
New laws
New laws of physics, of the quantum world, begin to operate here. Chemically it is the same, but in various physical properties, nano-gold is quite different from macro-gold.
Even in the nano-dimension, size matters. A 3 nanometre (nm) particle of cadmium selenide shines green, but emits red when its size increases to a bit more than 5 nm. Take the example of magnets. Magnetite, a composite oxide of iron, is a good magnet.
But its magnetic property changes as we cut chunks of it into smaller and smaller pieces. Below 40 nm in size, its magnetic properties actually become more pronounced, and it becomes what physicists call a superparamagnet.
At the same time, as the particle size reduces, the proportion of surface area it exposes also increases. This allows it to `stick' to material more avidly than in the bulk phase.
What the Rice university researchers have done is to exploit this nano-size behaviour of magnetite. They prepared 16-nm size magnetite particles, stirred up a bit of this material in a beaker-full of arsenic-contaminated water.
Large surface area
Two things happened. Magnetite, being an iron-containing material, has an affinity to bind to arsenic salts, and it did so very avidly, thanks to the large surface area it presents at this nm size.
This removed the dissolved arsenic very efficiently from the water. Secondly, they placed an external magnet under the beaker.
This external magnetic field induced the aggregation or clumping of the magnetite into large chunks, which could be decanted or filtered out, leaving arsenic-free water. What does it mean to Bangladesh, and other areas affected by arsenic-contaminated water?
The use of nano-magnetite and a small magnet helps remove the arsenic quickly and efficiently. Here then appears a method worth trying both at the small scale and at the larger community level. Nano-Davids for Mega-Goliaths!
D. BALASUBRAMANIAN
dbala@lvpei.org
Environmental Entrepreneur,Green Biz.NRN Murthy of Infosys says that we Indians are weak in execution.We need to realize the need and practice of gud project management. Form a group of competent Managers,Give them responsibilities and review the project from day One.
( WATER TREATMENT INDIA) incompetent people
incompetent people ,they blame others for their misery, don’t own up their own responsibility for their present state
They Try to Bring Others Down To Their Level
They Give Up Easily. Incompetent people don't have the persistence to stick to one path.
They Take the Easy Way Out, there is no shortcut to hardwork.
They Try to Bring Others Down To Their Level
They Give Up Easily. Incompetent people don't have the persistence to stick to one path.
They Take the Easy Way Out, there is no shortcut to hardwork.
Environmental Entrepreneur,Green Biz.NRN Murthy of Infosys says that we Indians are weak in execution.We need to realize the need and practice of gud project management. Form a group of competent Managers,Give them responsibilities and review the project from day One.
Subscribe to:
Posts (Atom)
