Dear Ms Bennet
I think this was the link you mentioned was not published.,
You may connect this to main discussion ,
Sure this brings with it the field learning and apprehensions.
This needs full support of the bench chemists and scientists.
Thanks for your support, it is and has been a great learning.
Request scientists , chemists on board from Pakistan and south Asia to join this discussion.
We need to bridge this gap amongst the field/ Application issues and the class room discussion.
Rgds and Thanks for your support once agan
M Jahangir
Water Pakistan.com
Islamabad
On Sat, Apr 30, 2011 at 4:16 AM, Meer Husain
<matrib...@yahoo.com> wrote:
Dear Mr. Sadiq,
Prechlorination by both Calcium Hypochlorite and Sodium Hypochlorite have been extensively used in municipal and small scale arsenic removal systems in USA for many years. A successful prechlorination depends on the chlorine demand and chlorine dose. Also you have to be aware of the shelf time of hydrochloride during the determination of dose for chlorination. Most importantly high concentration of iron in water is very effective for removing arsenic. If adequate iron is absent in the water in that case you can add ferrous/ferric iron, ferrous sulfate and without enough iron in water one can not effectively remove AS(III) from water.
After prechlorination, if you use cloth filter then you have to consider the followings:
1. Is your cloth filter is reusable? if so how would you collect the arsenic/iron residue from the cloth and how would you dispose the residue?
2. Do
you know how many cloth filters will be needed in a year? you have to consider the environmental economics of prechlorination, cloth filtration and collection and disposal of arsenic residue etc. 3. You have to test your filtration system on site for each location and in that case you have to depend on the field testing kits as well as lab analysis. This is because of the fact that water chemistry varies from time to time due changes in geochemistry of aquifer caused by both human activities and natural processes.
I have developed several systems including a cloth filter. My study indicates that a community based system would be very effective rather than that of individual household system .
Regards,
Meer Husain
Sadiq Wrote: Dear all,
Another way of simple method to remove As, Fe and Mn is, oxydizing by adding cl2 (liquid/solid) and simple filtration by cloth. I have tried this method and
successfully remove at a certain level. Most important thing is dosing. If optimum dose can't be determined chloramin[e?] may form. Another problem is the smell of Cl2 sometimes not accepted by users. This problem also be solved by filtering with activated carbon.
Thanks, Sadiq |
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