by Aadithyan J P
Chennai, Feb 22: The remaining sludge from the Kamarajar oil spill back in 2017, as a result of two oil tankers colliding, which released about 250 metric tonnes and severely damaged the Chennai coastline, is yet to be fully cleaned.
The KPL(Kamarajar Port Ltd.) have given the contract to the IOCL (Indian Oil Corporation Ltd.) to remove the slick and they are using the process of bio remediation to bring back the pollution to permissible limits.
Bio remediation a chemical process that is used to treat water soil and other subsurface materials by introducing external organisms that are bio engineered for the targeted degradation of pollutants. The benefit of this process is that it uses no chemicals and thus after the whole process is completed it does not pollute the environment.
Before the intervention of the IOCL, the levels of pollution as per test results were 8 percent, and after their process of bio remediation it was lowered to levels between 1 and 0.5 percent. This process involves introducing a special kind of bacteria that has been formulated in labs.
According to S K Puri, Chief General Manager of Bio energy at Faridabad, who was on site to oversee all operations, “these microbes are used to clean up the spilt oil. They are released into the sludge and eats it up as it is their food. And after this process is over, they are rendered inert and die off without any sustenance. They are frozen in cubes and transported to the site and are allowed to be dissolved into the oil.”
These organisms require ambient conditions to thrive and multiply, so the temperature cannot be neither too hot nor too cold. The ideal time to release them would be after the monsoon showers as the rain would dilute them. It is important that they are released in optimal conditions as they would breed faster and increase the rate at which the cleanup occurs, he added.
So far, we have cleaned about 184 metric tonnes and we had given the report, to the TN government who were very pleased. The whole process took about six months as we had released the microbes directly onto the affected areas in the open environment. We plan to treat the remaining slick in a closed vessel, in a process called confined bio remediation, where we can monitor and control the conditions, and since this is much more efficient it will only take about a month or so to clean up, said the GM.
Water and soil samples will be taken to gauge the levels of pollution of heavy metal and oil contamination and will be tested against the IS 10500 [Indian standard for drinking water quality].
CITY PULSE 