Remediation work to clear oil seepage in Tondiarpet in north Chennai began on Thursday with the U.S.-based company beginning to extract vapour from the contaminated soil and petroleum product from the groundwater.
Sources in the Tamil Nadu Pollution Control Board (TNPCB) said that the work is likely to go on for at least two years till the contamination within that 2-sq. km area is removed. Oil from an underground pipeline to Bharat Petroleum Corporation’s facility in the densely-populated Tondiarpet had leaked over a period of time contaminating water sources.
Residents first noticed the oil in mid-2012 and by July 2013, TNPCB intervened after media reports about the contamination. Experts from IIT-Madras were then asked to study and help decontaminate the locality. From February 2015, the U.S.-based company began its studies to clean up the area. The company set up 30 borewells to monitor how far the oil had spread.
“Luckily, it hadn’t spread much. Now, 20 remediation wells have been placed and through a soil vapour extraction system, oil in the sub-surface is removed. Using an air sparging system, oil in the groundwater is brought up by blowing bubbles into the water. Continuous samples of the water and soil will be collected and tested,” explained an engineer who is familiar with the process.
