Arsenic Removal from Ground Water - a Low Cost Filter Media

Material and Methods

Column filtration method: The column filtration method was used in this practical work.  This method requires a minimum financial investment and facilitates change of the filling material easily for cleaning and for any other corrections/amendments.  Three kinds of columns were used independently for comparing with each other to see the efficiency of particular column.  Different Arsenic positive samples (0.10 to 2.00 mg/l) were passed through these columns at the same input flow rate (200ml/hrs).

The filtered water was then tested for Arsenic, TDS and colour; lastly the results were compared with each other.  The first column contained sand, gravels, sieve, cotton cloth, glass beads and FeOOH gel.  The second column contained the same except the FeOOH gel which was replaced by Iron rust instead. The third column contained the same as the second column but with an extra layer of charcoal beneath the Iron rust.

Back wash is recommended in all the three columns.

I. FeOOH Gel prepared for Column Treatment: The gel of FeOOH can be prepared by using:

  • Sodium Hydroxide - NaOH - 500 ml
  • Ferric Chloride - FeCl3 - 500 ml
  • Sodium Silicate - Na2SiO3 - 500 ml

 

 

When these are all mixed in required proportions and stirred for about one to two hours, a gel like substance is obtained which has a definite iron-like property.

II. Treatment Using Rust: A common type of Rust from a thrown Cooler as we have obtained is shown in Figure 1 and a setup of Rust column in Figure 2 (this setup contained sand, gravels, glass beads, filter papers, sieve and cotton cloth)

Figure 1: Used Cooler as a source of raw rust

Figure 2: A full set-up of Rust Column 

III. Treatment using Rust + charcoal: The third and one of the most important methods for the removal of Arsenic from the groundwater is through Rust and charcoal treatment.  Charcoal has the property to decrease the unwanted impurities like colour and some biological impurities from the water.

 
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Thursday,
July 5, 2012
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2 comments

  • Reply sarrah sarrah July 7, 2012 at 2:58 am

    the concept seems great but i wanted to if the rust bed puts up some adverse impact like addition of ferric ions in water. secondly, what method did you use to detect the arsenic, was it atomic absorption or spectrophotometer? kindly reply me asap as i am looking forward to work on the similar concept.
    thanking in anticipation.

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