Some groundwaters contain more arsenic than WHO's, permissble limit. How can we remove arsenic from drinking water?
sorption ,have a good efficiency in arsenic treatment.
clay and, carbon active are good adsorbent.
coagulation ,pH adjusting, membrane filtration are acceptable solution.
choosing the acceptable method is related to As concentration and source of it.
a pilot plant study is very good method for testing the most benefit methods.
Biosorption. Here is a typical example for strontium.
Article Biosorption of the strontium ion by irradiated Saccharomyces...
You might consider this link for information and potential for home or site use.
http://www.pure-earth.com/arsenic-water-filter.htm
Reverse osmosis is another type system. Any system may need periodic maintenance or checking to detect when to renew filters or media. Customer support services may be available through companies that sell As removal systems to help identify capacity based on typical contamination level. More examples of water treatment equipment at varying costs and effectiveness are available on the internet.
sorption ,have a good efficiency in arsenic treatment.
clay and, carbon active are good adsorbent.
What kind of water treatment and materials do you have access too? Speciation of the arsenic is also important here. If working with As(III), you likely need an oxidation step (e.g. bleach or UV) before any sorption or filtration steps. Expensive solution: reverse osmosis; less expensive: iron precipitation (e.g. ferric chloride). If no water treatment infrastructure is in place, some parts of the world use sunlight to oxidize the arsenic, but this is not very effective. Again, works much better if the water is naturally high in iron.
Arsenic removal from water is recommended with a Reverse Osmosis System within your home or within a point-of-use water dispenser for clean drinking water. Reverse Osmosis is a process that forces water through a semi-permeable membrane under pressure that will leave contaminants behind and dispense more pure and healthy drinking water. Although most reverse osmosis systems are effective at removing arsenic as well as lead, pesticides and cysts, the semipermeable membrane within the system can grow over time as contaminants are continually pressured against it. Regular maintenance of your RO system can make sure arsenic filration will continue working as it should.
It is possible to use granules of iron oxides if you wont use iron chloride og iron sulfate as chemicals you are adding to the water. The granules can last for 1-5 year and must be replaced when arsenic increases again. The waste granules have high content of arsenic and must be considered as hazardous waste , likewise the sludge when using iron chloride and iron sulfate. Both methods are used in connection with normal sandfilters, so it is possible to remove excess iron.
The relation between arsenic and the need for iron can be seen at side 4 in:
https://naturstyrelsen.dk/media/nst/70150/ArsenManual2010.pdf
We are talking about drinking water, so for now there is no 100% guarantee that all nZVI-particles will be collected and will not get inside of a person. 10nm nZVI-particles pass through the intercellular barriers.
Dear Sudip Saha,
Ferric hydroxides show best adsorption performance for arsenic removal from drinking water. The ferric hydroxides can be generated by oxidising the dissolved Fe(II) in the raw water (if applicable), or by precipitation after dosing Fe-salts (e.g. FeCl3). (see attached scheme).
In fact, the best and simplest way is to use a fixed-bed adsorption filter equipped with a granulated ferric hydroxide media. The product GEH (or GFH) Granular Ferric Hydroxide was developed in the 1990s at the Technical University of Berlin, Germany, and it is now produced and distributed by our company GEH Wasserchemie. There is a 20 years practical experience with this adsorbent media in several hundereds full-scale drinking water treatment plants world-wide.
Please contact me directly if you need more information.
Best regards
Carsten
I agree with Carsten Bahr for your nice figure and comment.
regards
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