[[Image:de-fluor icon.png|right|100px80px]][[Image:defluoridation unit.jpg|thumb|right|200px|Household defluoridation unit (HDU). Photo: Addis Ababa University.]][[Image:defluoridator.jpg|thumb|right|200px|The EnDeCo Institutional Defluoridator. It can be made at any desired capacity, normally in the range >20 m3 for a raw water fluoride of 5 mg/L. Photo: [http://www.de-fluoride.net/defluoridation.html De-fluoride.net.]]][[Image:contact precipitation unit.jpg|thumb|right|200px| A Contact Precipitation Unit set up as a demonstration plant and run for a couple of years. Since, it has been operating as a simple Bone Char community plant. <br>Photo: [http://www.de-fluoride.net/defluoridation.html De-fluoride.net.]]]
[[Image:defluoridation unitHigh levels of fluoride in groundwater have been reported parts of in Ethiopia, Malawi, Kenya and Tanzania and can lead to health problems including dental fluorosis, osteosclerosis, thyroid problems, growth retardation and kidney failure.jpg|thumb|right|250px|Household defluoridation unit A WHO report shows excessive fluoride intake (HDU3-6 mg/L)can lead to severe and permanent bone and joint deformations of skeletal fluorosis. <br>Photo: ADDIS ABABA UNIVERSITY.]][[Image:defluoridator.jpg|thumb|right|250px|The EnDeCo Institutional Defluoridator. It can be made at any desired capacity, normally in the range >20 m3 for a raw consumption of drinking water fluroide of 5 with higher fluoride concentrations (10 mg/L. Photo: [http://www.de-fluoride.net/defluoridation.html De-fluoride.net.]]][[Image:contact precipitation unit.jpg|thumb|right|250px| A Contact Precipitation Unit set up as a demonstration plant ) can lead to crippling fluorosis, which causes the hardening and run for a couple calcifying of years. Since, it has been operating as a simple Bone Char community plant. <br>Photo: [http://www.de-fluoride.net/defluoridation.html De-fluoride.netthe bones.]]]
High levels Most of the methods currently available for the removal of fluoride in groundwater has been reported parts of in Ethiopiafrom drinking water are either too expensive, Malawitechnically unfeasible for household use, Kenya and Tanzania and can lead to health problems including dental fluorosis, osteosclerosis, thyroid problems, growth retardation and even kidney failureor will change the water quality. WHO report shows excessive The removal of fluoride intake (3-6 mg/L) can lead to severe from water using aluminium hydroxide has been investigated and permanent bone and joint deformations of skeletal fluorosis and the consumption of drinking water with even higher fluoride concentrations a household defluoridation unit (10 mg/LHDU) can lead to crippling fluorosis, which causes the hardening has been designed and calcifying of the bonestested.
Most of ===Suitable conditions===Treatment at the methods currently available for household level has several advantages over treatment at the removal of fluoride from drinking water community level. Costs are either too expensivelower, are technically unfeasible as defluoridation can be restricted to the demand for household use or change cooking and drinking which is usually less than the total water qualitydemand, which gives people a sense of ownership. The removal of fluoride from water using aluminium hydroxide has been investigated and a household defluoridation unit (HDU) has been designed and testedThis treatment option may be feasible in less developed countries especially in rural areas, where settlements are scattered.
==Suitable conditions==Treatment of fluoride contaminated water at household level has several advantages over treatment at community level. Costs are lowerthe source is carried out on a large scale under the supervision of skilled personnel, as defluoridation can be restricted to without direct involvement of the demand for cooking users, and drinking which where the affordability of treatment is usually less than taken for granted. In such cases the total water demand method of treatment is well-established and make people a sense well-controlled. However, it requires major input of ownership. This treatment option resources and may be feasible have serious limitations or disadvantages in less -developed countries ; especially in rural areas, where the settlements are scattered. This is especially adopted in developed countries.
Treatment of fluoride contaminated water at the source is carried out on a large scale under the supervision of skilled personnel, without direct involvement of the users, and where the affordability of treatment is taken for granted. In such cases the method of treatment is well established and well controlled. However, it requires major input of resources and may have serious limitations or disadvantages in less-developed countries; especially in rural areas where the settlements are scattered. This is especially adopted in developed countries. ===Construction, operations and maintenance===[[Image: Nalgonda technique.jpg|thumb|right|250px200px|The Nalgonda Technique diagram.<br> Photo: [http://www.de-fluoride.net/defluoridation.html De-fluoride.net.]]]There are several methods which have been developed to reduce fluoride from contaminated water, such as adsorption, ion exchange, precipitation, electrodialysis and reverse osmosis. These methods have rarely been implemented in developing countries, except in some areas, due to insufficient removal efficiency, unaffordable costs, and complicated operation and maintenance, (particularly for rural populations).
The most common defluoridation methods used in developing countries at present are sorption on activated alumina, co-precipitation with aluminium hydroxide (known as the Nalgonda Technique) and sorption on bone char.
[[File:fluoride absorbers.jpg|thumb|centernone|400px500px|Materials that absorb fluoride. Chart:[http://www.de-fluoride.net/defluoridation.html De-fluoride.net.]]]
===Field experiences===
In the Rift Valley regions of Ethiopia where there is a high fluoride concentration, the settlement of the people in the rural areas is scattered. Therefore to combat the problem of fluorosis, a household treatment system is a reasonable approach. Thus it is necessary to develop a household-scale defluoridation unit that can be applicable in these areas.
==Field experiences=Manuals, videos and links===In the Rift Valley regions * [http://www.appropedia.org/Water_Defluoridation#cite_note-apptechTZ-32 Water Defluoridation]. A huge amount of Ethiopia where there is a high information on fluoride concentration, the settlement of the people in groundwater around the rural areas is scatteredworld, and how to remove it. Therefore to combat the problem of fluorosis household treatment system is a reasonable approachAppropedia. Thus it is necessary to develop a household scale defluoridation unit that can be applicable in these areasorg.
==Manuals, videos, and links==
* [http://academicjournals.org/ijps/PDF/Pdf2008/Jan/Sajidu%20et%20al.pdf Groundwater fluoride levels in villages of Southern Malawi and removal studies using bauxite.] International Journal of Physical Sciences Vol. 3 (1), pp. 001-011, January, 2008.
* [http://docs.watsan.net/Scanned_PDF_Files/Class_Code_2_Water/257-12521.pdf Application of defluoridation plants for rural water supply in North Gujarat (India)]. Master of Science thesis by R A Jethwa. March 1995.
===Acknowledgements===* WONDIMAGEGNWondimagegn, AGEGNEHU ALEMUAgegnehu Alemu. [http://etd.aauwww.edulibsearch.et/dspace/bitstream/123456789/2531com/1view/193 1301608 DEVELOPMENT OF HOUSEHOLD DEFLUORIDATION UNIT BASED ON ALUMINIUM OXIDE HYDROXIDE.] December, 2008.
* Dahi, Eli. [http://www.de-fluoride.net/defluoridation.html Defluoridation.] March, 2009.
