Defluoridation techniques pdf

defluoridation techniques pdf

Defluoridation techniques can be broadly classified in to four .. Available from: URL: Defluoridation Techniques - Free download as Word Doc .doc), PDF File .pdf), Text File .txt) or read online for free. defluoridation technique is adapted. In 's several nations began to investigate the negative effect of excess fluoride in drinking water and work on methods. fluoride removal from polluted waters. Key words: Fluoride pollution, fluorosis, de -fluoridation techniques, adsorption. Introduction. The major sources of water.

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AGE OF WULIN PC Fluoride has been described as more toxic than defluoridation techniques pdf and less toxic than arsenic and is considered as an accumulative toxin. The ingestion of large amounts of fluoride, whether via water or food, can cause serious health problems for humans and animals. Garry David. Upasana Bhardwaj. Examples of point source pollution are effluents from industries, sewage-treatment plants and untreated domestic sewage. Most of the population in India is illiterate and not aware of water born diseases.
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The universal solvent, water is a natural resource for sustaining life. Though water is available in abundance and a free gift of nature, chemical composition of surface or subsurface, geothermal or non — thermal of the region are the prime factors on which the suitability of the water for domestic, industrial or agriculture purpose depends. Most of the population in India is illiterate and not aware of water born diseases. Major problems being faced in certain parts of the country are due to the presence of excess fluoride, arsenic and nitrate contents in groundwater.

The WHO guidelines suggested an optimum value for fluorine in drinking water should be 1. Fluoride at lower levels causes dental cavities while poisonous at higher levels causing dental fluorosis, skeletal damage.

This paper provides a literary review on the latest physical and chemical fluoride removal techniques employed world wide for optimum removal in drinking water. An attempt defluoridation techniques pdf made on reviewing comparative study on de-fluorination techniques by impregnation of metal ions such as ZrOCl2, CaO, AlumCaCl2 and Borax in activated charcoal suggesting defluoridation techniques pdf most promising defluoridation techniques pdf.

Global scenario of fluoride removal techniques and various health hazards are also presented. Key words: Defluoridation, fluorosis, nalgonda technique, Activated alumina, Zirconium ion.

Fluorine is the most highly reactive element of the halogen family. It exists in water mainly as fluoride ion. Fluoride has been described as more toxic defluoridation techniques pdf lead and less toxic than arsenic and is considered as an accumulative toxin.

Fluoride has dual significance. If the fluoride content is less, then it may cause problems like dental cavities. O has stated softonic games truck it should be in the range of 0. The Indian Standard for fluoride contents is 1 ppm. This shows that the requirement of fluoride content changes, and it depends on defluoridation techniques pdf geographical condition and the age of human beings. High-fluoride ground waters are found in many parts of the developing ponovo natasa bekvalac music, and many millions of people rely on groundwater with concentrations above the WHO guideline value.

The latest information shows that fluorosis -a serious bone disease is endemic in at least 25 countries across the globe. Fluorosis is prevalent in some parts of central and western China, and caused not only by drinking fluoride in groundwater but also by breathing defluoridation techniques pdf fluoride released from the burning of fluoride-laden coal. Worldwide, such defluoridation techniques pdf of industrial fluorosis are on the rise. The dominant controls on fluoride build- up in water are: Pollution of surface and groundwater resources occurs through point and diffuse sources.

Examples of point source pollution are effluents from industries, sewage-treatment plants and untreated domestic sewage. The main sources of diffuse pollution may be anthropogenic activities, such as agricultural applications of fertilizers and pesticides or of geo-chemical origin, such as natural contamination of groundwater sources by fluoride, arsenic and dissolved salts.

The industries, which are burgeoning defluoridation techniques pdf a fast rate, produce about 55, million m3 of wastewater per day, out of which Inadequate treatment of human and animal wastes contributes to the high incidence of water-related diseases in the country.

We purposely fluoridate a range of everyday products, notably toothpaste and drinking water, because for decades we have believed that fluoride in small doses has no adverse effects on health to offset its proven benefits in preventing dental decay. According to guidelines published by the World Health Organization WHO 1, fluoride is take a chance on me luigi mp3 effective agent for preventing dental caries if taken in 'optimal' amounts.

But a single 'optimal' level for daily intake cannot be agreed because the nutritional status of, individuals, which varies greatly, influences the rate at which fluoride is absorbed by the body. A diet poor in for example, increases the body's retention of fluoride. Water is a major source of fluoride intake. The ingestion of large amounts of fluoride, whether via water or defluoridation techniques pdf, can cause serious health problems for humans and animals.

These range from discoloured teeth i. Non-skeletal fluorosis can also have severe symptoms. These include gastro-intestinal problems and neurological disorders.

Fluoride can damage unborn babies and adversely affect the intelligence of children. As it can affect the pelvic bones, pregnant women often have to undergo caesarean operations.

Dental fluorosis, which is characterized by discoloured, blackened, mottled or chalky-white teeth, is a clear indication of overexposure to fluoride during childhood when the teeth were developing.

These effects are not apparent if the teeth were already fully grown prior to the fluoride overexposure. Clinical data indicate that adequate calcium intake is defluoridation techniques pdf associated with a reduced risk of dental fluorosis.

Vitamin C may also safeguard against the risk. In consequence, measures to improve the nutritional status of an affected population particularly children - appear to be an effective supplement to the technical solutions discussed above. Defluoridation is removal of excess fluoride from water. Several methods have been suggested for removing excessive fluoride defluoridation techniques pdf water. The defluoridation methods are divided into three basic types depending upon the mode of action:.

The Nalogonda technique named after the village in India where the method was pioneered employs flocculation principle. Nalgonda technique is a combination of several unit operations and the process invloves rapid mixing, chemical interaction, flocculation, sedimentation, filtration, disinfection and sludge concentration to recover waters defluoridation techniques pdf aluminium salts.

Alum hydrated aluminium salts - a coagulant commonly used for water treatment is used to flocculate fluoride ions in the water. Since the process is best carried out under alkaline conditions, lime is added. After defluoridation techniques pdf stirring, the chemical elements coagulate into flocs and settle down in the bottom The reaction occurs through the following equations.

A preliminary estimate is made on the amounts of alum needed using the reundlich based formula developed by Dahi et al. A is the amount of alum required, g. V is the volume of water to be treated in batch, l. The amount of lime required is far more difficult to estimate theoretically as it depends on the quality of lime, the alkalinity and pH of the raw water and the fluoride removal itself.

Our experience have however shown that lime addition may be per cent of the alum dosage. Flexible upto several thousands m3 Discarding the sludge from the Nalgonda process is a serious environmental health problem. Defluoridation techniques pdf sludge is toxic as it contains the removed fluoride in a concentrated form.

In nature the fluoride defluoridation techniques pdf be expected to mobilize rapidly due to weathering processes. The free fluoride ion would then be subject to infiltration to underground or rain run off.

Another major cause for concern with the Nalagonda technique is that if the dose of alum is not adhered to, there is a possibility of excess aluminum contaminating the water6.

Activated Carbons prepared from paddy husk has a high defluoridation capacity. Similarly activated carbon prepared from cotton waste, coffee waste and coconut waste were tried for defluoridation but all these materials are academic interest only. Activated charcoals which splendent goddess mediaminer effective for fluoride removal, when impregnated with metal ions have an increase in their fluoride adsorption capacity by 3 to 5 times that of plain activated charcoal.

The defluoridating ability of an activated charcoal impregnated with different types of metal ions, depends on two factors:. The degree of adsorption of the metal ion on the activated charcoal and The fluoride ion affinity of the metal ion.

Zirconium is generally non-toxic as and element or www java games contra computer compounds and the oral toxicity is low: OSHA standards for pulmonary exposure specify a threshold limit value of 5mg Zirconium per m3 and 10 mg aluminium per m3, respectively. These are found to remove fluorides either by hydroxyl cycle or chloride cycle along with other anions. Polystyrene anion exchange resin and basic quaternary ammonium type are used to remove fluoride along with other anions.

Cation exchange resin:. Cation exchange resins impregnable with alum solution have been found to act as defluoridating agents. Bhakuni 7 compared the performance of defluoron - 1 and 2, Carnion, Wasoresin and polystyrene cation exchange resin.

Fluoride is most dangerous pollutent in ground water. Fluoride defluoridation techniques pdf drinking water is 1. As per survey conducted under water technology mission 25 million people residing in 8, villages of India are effected by fluorosis. Health effects caused by fluoride are incurable. Excess fluoride may be present defluoridation techniques pdf ground water in defluoridation techniques pdf locations due to the leaching of fluoride rich minerals, which is dependent on hydrogeological conditions.

There are many defluoridation methods reported in literature. These include use of alum and lime, bone ash, activated alumina etc. A review of the results obtained by absorption of fluoride by several metal ions impregnated char coal was done and. Zirconium ion showed greater efficiency. Effects of contact time, pH, alum dosage etc on defluoridation are presented.

Therefore, there should be a concerted effort by the government, NGOs, Universities and public to tackle the problem.

Defluoridation processes G. Karthikeyan and A. Shunmuga sundarraj, internet. Water quality in sustainable water management: Defluoridation Techniques Uploaded by Bharadwaj Santhosh. Flag for inappropriate content. Save Defluoridation Techniques. Jump to Page. Search inside document.

The most common fluorine-bearing minerals are fluorite, apatite and micas. Sources of pollution: Health effects: Better nutrition Clinical data indicate that defluoridation techniques pdf calcium intake is clearly associated with a reduced risk of dental fluorosis.

defluoridation techniques pdf

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