Arsenic Removal from Ground Water - a Low Cost Filter Media

Arsenic is a major environmental pollutant and naturally occurs in deeper levels of groundwater.  These contaminated drinking water has affected countries like India (West Bengal), Bangladesh, China, Taiwan, Thailand, Chile, Argentina and Romania.  Concentrations of arsenic in these affected areas are several times higher than the maximum contamination level (MCL) (10 µg/l). 

Arsenic exposure to human results in degenerative, inflammatory and neoplastic changes of skin and bodily functions. There is no particular remedial action for chronic arsenic poisoning, and low socioeconomic status and malnutrition only serve to increase the risk of chronic toxicity.  A 2011 study found that over 1 in 1,000 people in more than 70 countries are probably affected by Arsenic poisoning.

Introduction

Arsenic in groundwater is a serious problem across India.  This study was done to establish the potential of removing Arsenic from groundwater through waste Iron rust (Fe2O3) which is easily available.  It was shown that the Arsenic removal capacity of this media is more than 90% and issuperior to using hydrous ferric oxide (FeOOH) gel for removing Arsenic, Total Dissolved Solids (TDS) and colour.  Various experiments were then conducted to find the best method for Arsenic removal capacity of rust, and they were compared with the results of FeOOH for various water parameters.  Iron rust turns out to be most efficient media in removing Arsenic from groundwater.

For the longest time, Arsenic pollution of the groundwater has created serious threat to a number of districts in West Bengal and parts of India like Bharatpur City (Rajasthan), Aligarh (UP) and Darbahnga (Bihar).  An estimated population of about 30 million people living in these parts of India is affected by the Arsenic content which is much higher than the WHO limit.  As a side note, the Bureau of Indian Standards (BIS) has already revised the limit of Arsenic in drinking water from 0.05 to 0.01 mg/L (5 to 1 ppb) with effect from 2003.

Table I : Affected Areas by Arsenic Toxicity

District and City

Concentration in mg/l

South 24 Parganas, West Bengal

0.06-3.20

North 24 Parganas, West Bengal

0.06-1.28

Malda, West Bengal

0.05-1.434

Nadia, West Bengal

0.05-1.00

Murshidabad, West Bengal

0.05-0.90

Bharatpur City, Rajasthan

0.4-0.5

Darbahnga, Bihar

0.05-0.1

(Source: A Study on Arsenic Contamination in Indian Urban, Sub-Urban & Rural Area - WHO Report)

These results provided substantial evidence of prolonged Arsenic ingestion by the people through food chain as well as drinking water sources. Hair, nails, scales, urine and liver tissue analysis of people living in these affected areas showed elevated levels of Arsenic, further confirming that the source of Arsenic is geological.  The contamination is mostly reported from aquifers at a depth of 20-80 metres below ground.

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Thursday,
July 5, 2012
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2 comments

  • Reply Shailesh Jha Shailesh Jha July 7, 2012 at 2:58 am

    Hi Sarrah

    Its great to hear from you and would definitely resolve whatever your points for concerns are.
    Firstly, the Rust Bed in initial phase has shown some adverse impact such as Color & Increase in Iron. But with some addition of Charcol to the Bed (Module) same can be resolved.
    Secondly, for detection of Arsenic, I have used Merk Testing kit based on Adsorption process.
    The kit needs lil working experience to use as it might prove not efficient for freshers.

    Hope this might have resolved some of your issues and if any left, please feel free to contact me.

    Thanks & Regards
    Shailesh Jha
    Jr. Design Engineer -PHE
    +91-7838812751

  • 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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