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Arsenic Removal Technologies
NOT Certified for Sale
The BETV-SAM project field tested 12 arsenic removal technologies (ARTs) and only certified two technologies. The following ARTs have failed to generate adequate
quantities of treated water, their performance was not verified, and have not been certified for sale in Bangladesh.
Kanchan Arsenic Filter (KAF)
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KAF is and iron-amended BioSand filter that was developed by the Massachusetts Institute of Technology (MIT), the Environment and Public Health Organisation
(ENPHO), a Napali non-governmental organization (NGO), and the Centre for Affordable Water and Sanitation Technology (CAWST), a Canadian NGO. It is a gravity filter and is designed for intermittent use. The water is poured over nails and slowly filtered through a bed of fine and coarse sands and gravels. It was thought that iron nails will corrode and release iron (oxyhydr)oxide as groundwater filters through the nails, which then adsorbs and removes arsenic from arsenic contaminated well water.
The technology failed to generate arsenic-safe water for reasons discussed in the KAF verification report and therefore it was not certified for sale in Bangladesh.
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MAC - Chemicon Arsenic Removal Technology (MAC-C ART)
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This is a sorptive technology, operates in flow through mode, and can process approximately 600 litres of arsenic contaminated groundwater in an hour.
Groundwater is pumped directly into the inlet and treated water is collected from the outlet. Iron dissolved in ground water is oxidized in the oxidation chamber (firs column)
and filtered out in the iron removal filter (second column) as groundwater flows through the unit. Finally, arsenic dissolved in groundwater is adsorbed and removed by arsenic
removal media and treated water leaves the unit.
The technology was unable to produce chemically safe drinking water for reasons that are discussed in the MAC-C verification report and was not certified for sale in Bangladesh.
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READ F Well Head Unit
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The READ F Well Head Unit is a sorptive technology, which is operated in flow through mode and has the capacity to process approximately 120 litres of arsenic contaminated groundwater in an hour.
Groundwater is pumped directly into the unit and treated water is collected from the outlet. The proponent claimed that dissolved iron is oxidized and removed through
filtration and dissolved arsenic is adsorbed and removed by arsenic removal media as groundwater passes through the unit.
The technology has been tested and failed to meet the proponent's performance claim for reasons that are discussed in the technology verification report. Therefore, it was not
certified for sale in Bangladesh.
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Coagulation Based Technologies:
CIWP (Canadian International Water Purification) for household use
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Type of Technology: coagulation/floculation using a specific amount of ferric sulphate and enough sodium hypochlorite to create a distinctive chlorine odor upon stirring in a normal bucket of well water. The water is left for one hour. The water after settling is gently passed through a filter to remove the suspended solids.
This technology was not certified for sale for reasons outlined in the verification report (PDF).
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Earth Identity Project (EIP)-Star Stevens for household use
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Type of Technology: coagulation/flocculation using a specific amount of ferric sulphate and calcium hypochlorite added by a measuring spoon into a normal bucket. The water mix is thoroughly stirred and left to stand for 10-15 minutes. The water after settling is gently passed through a second bucket containing a sand filter media followed by granular activated carbon filter sequentially.
This technology was not certified for sale for reasons outlined in the verification report (PDF).
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Adsorbent Based Technologies:
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Type of Technology: This is a flow through technology, where the arsenic contaminated well water is pumped out of the well and into the WW ART unit. The well water is pumped into an overhead storage tank, where it is also spiked with sodium hypochlorite for the oxidation and removal of dissolved iron. It is allowed to stand in the over head tank for about 30 min and then flowed through the unit. The dissolved arsenic is adsorbed by arsenic removal media and the arsenic-safe water exits the WW ART unit.