IIT-K develops tech to ?clean? soil
SCIENTISTS AT the Indian Institute of Technology (IIT-K) have developed a new cost-effective technology for cleaning soil that has been contaminated by deadly metals like chromium, lead, distillery effluents, phospho-gypsum iron and zinc.india Updated: Mar 15, 2006 00:21 IST
SCIENTISTS AT the Indian Institute of Technology (IIT-K) have developed a new cost-effective technology for cleaning soil that has been contaminated by deadly metals like chromium, lead, distillery effluents, phospho-gypsum iron and zinc.
The technology was developed by Dr Rajiv Shekhar and his tem members, K Sanjay, RP Das, A Arora, m Manna, PP Sahoo, D Pradhan and GP Bajpai.
The new technology is called ‘Electromediation’, in which a DC electric field is applied across electrode pairs placed in the ground. The contaminants in the liquid phase in the soil are moved out under the action of the field to electrode wells where they are then pumped out.
Dr Shekhar said electromediation can be used to remove a variety of heavy metals from soil including lead, arsenic, cadmium, zinc and copper, water-soluble organics and desalination of low porosity soil.
He said experiments have shown that electromediation can also be used to clear heavy metal-polluted river sediments. Experiments have also confirmed that electromediation was a viable technique for cleaning contaminated soil. In Kanpur, the technique was used and it removed about 85 per cent chrome (VI) from an industrial dichromate residue, he added.
Speaking of the need to develop the technology, Dr Shekhar said, “We have not paid enough attention to the role of solid wastes in the soil so far.
Over the years, industrial waste has been dumped indiscriminately, without treating it through proper waste-management techniques, which kept on contaminating the soil and causing degradation.” He said that contaminated soil was a recipe for disaster, as it polluted not only the underground water but also the crops sown on the contaminated soil.
Referring to a few studies on growing soil contamination, Dr Shekhar said, a study of agriculture fields around Hyderabad, showed alarming heavy metal concentration in the soil. Similarly, a study of use of distillery effluents in irrigation in some areas of Maharashtra, it was found that reasonably high concentrations of heavy metals were present in distillery effluents and the sludge settled at the bottom of the disposal pond, causing soil contamination.
Heavy metal contamination of coastal sediments was also assuming dangerous proportions. These concentrations were found from Kandla in the north to Porbandar in the south along Saurashtra and Kutch regions, he added.
Studies in Bokaro and Bhilai suggested the danger of lead contamination of adjoining soil and water resources due to fly sah, blast furnace lag and mine tailings from from copper iron and zinc Dr Rajiv said..