[[Image:Ceramic_filter_icon.png|right|80px]][[Image:arsenic removal.jpg|thumb|right|250px200px| Arsenic removal system: oxidation method. <br>Photo: Ngai.]][[Image:arsenic removal two.jpg|thumb|right|250px200px|Magc-Alcan Filter (left) and Nirmal Filter (right): adsorption method. Photo: Ngai.]]__NOTOC__ <small-title />
There are at least five ways to remove arsenic from drinking water. The adsorption method, the coagulation-flocculation method, the surface complexation method, a Kanchan arsenic filter, or removal by oxidation.
Instead of adding chemical oxidants such as chlorine or permanganate, reactive oxidants are produced photo chemically with sunlight.
===Construction, operations and maintenance===
[[Image:shapla filter.jpg|thumb|right|200|Shapla arsenic filter. Photo: Ngai.]]
[[Image:2-Kolshi filter.jpg|thumb|right|200|2-Kolshi arsenic filter. Photo: Ngai.]]
Contaminated water is poured into the top of the filter on an intermittent basis. The water slowly passes through the diffuser, and percolates down through the biolayer, sand and gravel. Treated water naturally flows from the outlet. The biolayer is the key pathogen removing component of the filter. Without it, the filter is significantly less effective. It may take up to 30 days to establish the biolayer depending on inlet water quality and frequency of use. The water from the filter can be used during the first few weeks while the biolayer is being established, but disinfection is recommended during this time, as during regular on-going use.
Much more information and details on the Kanchan arsenic filter: [http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0CFYQFjAB&url=http%3A%2F%2Fwww.cawst.org%2Fassets%2FFile%2FHWTS_Fact_Sheet_KAF/assets/File/HWTS_Fact_Sheet_KAF.pdf&ei=gz72T6esPOmy2QXl8-ToBg&usg=AFQjCNHExV2LsQy4IgoZzMR2avHnREOnsg&sig2=ClJFwW7vj9UkNrgU-4udPA Household Water Treatment and Safe Storage Factsheet: Kanchan Arsenic Filter.]
'''Oxidation: Passive'''<br>
* The water can then be filtered through textile cloth or clay filters
===Costs===
'''Adsorption: Magc-Alcan filter'''<br>
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===Field experiences=={|style="width: 70%; text-align: justify; background-color: #f5f5f5;" |[[Image:rsr 476.jpg|thumb|none|200px|<font size="2"><center>Project 476</center></font>|link=http://www.akvo.org/rsr/project/476/]]|'''AKVO RSR Project:''' [http://www.akvo.org/rsr/project/476/ Ensure access to safe water and sanitation]Salinity, arsenic, lack of proper IWRM, and incidence of natural disasters in the three districts of the Southwest coastal belt of Bangladesh cause a lot of socioeconomic and health related problems. The programme is right-based and strengthens knowledge and capacity following projects make use of community WASH groups as well as local government institutions. As problems are multifaceted, the programme uses a multi-pronged strategy and facilitates partnership with existing institutional stakeholders relevant for WASH sector.|} {|style="widtharsenic filtration: 70%; text-align: justify; background-color: #f5f5f5;" |[[Image:rsr 769.jpg|thumb|none|200px|<font size="2"><center>Project 769</center></font>|link=http://www.akvo.org/rsr/project/769/]]|'''AKVO RSR Project:''' [http://www.akvo.org/rsr/project/769/ Life-WASH]Similar to natural disasters, the project area is severely affected with excessive saline intrusion both in the groundwater and surface water mixed with unacceptable level of iron and arsenic (in the groundwater). The project will directly benefit 3350 households to have a solution regarding the problems of safe drinking water, sanitation and hygiene.|}
{|style="border: 2px solid #e0e0e0; width: 7060%; text-align: justify; background-color: #f5f5f5e9f5fd;" cellpadding="2"<!--rsr logo here-->|- style="vertical-align: top" |[[Image:akvorsr logo_lite.png|center|60px|link=http://akvo.org/products/rsr 770/]]| <!--place holder-->|[[Image:akvorsr logo_lite.png|center|60px|link=http://akvo.org/products/rsr/]]<!--project blocks here-->|- style="vertical-align: bottom"|[[Image: rsr 476.jpg|thumb|nonecenter|200px140px|<font size="2"><center>[http://rsr.akvo.org/project/476/ RSR Project 770476]<br>Ensure access to safe water and sanitation</center></font>|link=http://wwwrsr.akvo.org/rsr/project/770476/]]|'''AKVO RSR Project[[Image:''' rsr 769.jpg|thumb|center|140px|<font size="2"><center>[http://wwwrsr.akvo.org/project/769/ RSR Project 769]<br>Life-WASH</center></font>|link=http://rsr.akvo.org/project/770769/ Intervention Efforts in WASH]]The project is located at Magura Union under Tala Upazila of Satkhira district, covering 14 villages|[[Image:rsr 770. The project proposed for jpg |thumb|center|140px|<font size="2 years and the total population coverage is about 22,000 with the household number at 4,500"><center>[http://rsr.akvo. The site is org/project/770/ RSR Project 770]<br>Intervention Efforts in a remote area, socioeconomically backwards with a lack of WASH facilities</center></font>|link=http://rsr.akvo. The org/project planned to educate the community and install PSF, Rainwater harvesting, TW & WATSAN./770/ ]]
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===Acknowledgements===* [http://www.googlesswm.cominfo/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&ved=0CHMQFjAC&url=http%3A%2F%2Fwww.cawst.org%2Ffr%2Fresources%2Fpubs%2Fcategory%2F25category/implementation-facttools/water-sheetspurification/hardware/point-academic%3Fdownload%3D40%253Ahwtsuse-factwater-sheetarsenictreatment/arsenic-removalpdfoct09&ei=oi32T5bROeWW2AWlremoval-fDCBg&usg=AFQjCNHtsMduzuzEZMNKHgbl2BN1dHjr2g&sig2=VgGZabK2qsBHhJQkLL2TKQ Household Water Treatment for Arsenic Removal Fact Sheet: Adsorption.] CAWSTRaju Shrestha, Environment and Public Health Organisation, ENPHO.* [http://wwwresources.googlecawst.comorg/asset/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CG4QFjAA&url=http%3A%2F%2Fafghanlivelihoods.com%2Fvirtualarsenic-removal-library%2FShelter%2Fbiosandfact-filtration%2Fresources%2Fcasesheets-studies%2Fcaseadsorption_fr French Factsheet]. CAWST.* [http://resources.cawst.org/asset/arsenic-studyremoval-koshishfact-pakistan.doc&ei=STv2T4uhOvO_2QXxwJjaBg&usg=AFQjCNGUyPcn5C4VZdt_mjYo0sheets-0MktUnkw&sig2=yBKPzMiE6wkNRWtSR3kTPg coagulation_fr Household Water Treatment for Arsenic Removal Fact Sheet: Coagulation-Flocculation.] CAWST. (French version).* [http://www.googlesswm.cominfo/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CGkQFjAA&url=ftpsites/default/files/reference_attachments/CAWST%3A202009%2F20Household%2Fftp.wpro.who.int20Water%2Fscratch20Treatment%2FENH20and%2FHWTS20Safe%2FWHO20Storage%2520Final20Fact%2FParticipant20Sheets%2520Manual20Academic%2FAppendices20Arsenic%2FParticipant20Removal%2520Manual_Appendix%25202_HWTS%2520Fact%2520Sheets_2011-09-05%2F6_Arsenic%2520Removal%2FHWTS%2520Fact%2520Sheet_Arsenic%2520Removal_Complexation_2011-0620Complexation.doc&ei=JT32T7b3F4Ow2QW97pn8Bg&usg=AFQjCNHvayfxy_1Ml3uEd_7Y9fhbmyQJcA&sig2=ViTGkFqtns4j4WaOjEVQPQ pdf Household Water Treatment for Arsenic Removal Fact Sheet: Surface Complexation.] CAWST.* [http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0CFYQFjAB&url=http%3A%2F%2Fwww.cawst.org%2Fassets%2FFile%2FHWTS_Fact_Sheet_KAF/assets/File/HWTS_Fact_Sheet_KAF.pdf&ei=gz72T6esPOmy2QXl8-ToBg&usg=AFQjCNHExV2LsQy4IgoZzMR2avHnREOnsg&sig2=ClJFwW7vj9UkNrgU-4udPA Household Water Treatment and Safe Storage Factsheet: Kanchan Arsenic Filter.] CAWST.
* [http://www.cawst.org/en/resources/pubs/category/24-fact-sheets-simplified Household Water Treatment Fact Sheets.] CAWST.