Microbes to give oil sludge eco-friendly burial


CHENNAI: Scientists from Indian Oil Corporation began the process of treating over 100 tonnes of oil sludge at Ennore Port using indigenous technology involving a cocktail of bacteria and nutrients on Saturday. The sludge was removed from the shoreline in the last one week following the collision of Dawn Kanchipuram and BW Maple which led to the leak of heavy furnace oil into the sea. Another 39 tonnes of oil sludge was manually removed from the shoreline at Ennore on Saturday.

The bacteria would eat up the hydrocarbons present in the sludge and the soil would turn oil-free in three months. A large pit was dug in a secluded location inside Kamarajar Port in which the oil sludge was discharged and the treatment process called bio-remediation got underway. The treatment process is being supervised by a team from the research and development division of IOC that has arrived from Delhi following instructions from the ministry of petroleum and natural gas.About 70 workers are involved in the job.

While an inquiry into the accident has been ordered by the DG shipping and discussions with the ship owners were on regarding payment of claims, Rajya Sabha MP Kanimozhi has written to union minister for shipping, road transport and highways Nitin Gadkari urging the Centre to intervene and conduct a probe.

IOC DGM R&D SK Puri, who was one of the two IOC scientists to supervise the treatment process, said they have air-lifted 500kg of bio-innoculum (microbes) and 100kg of nutrients to Chennai which is sufficient to treat about 500 tonnes of oil sludge. They would require one kg of bacteria and nutrients to treat one tonne of sludge. The patented technology has already been used in treating more than 1,000 tonnes of sludge across the country including those from the Mumbai oil spill in 2010. Deputy manager, research, biotechnology department, IOC, Manoj Kumar Upreti, said the oil sludge was mixed with fresh soil. A mixture of microbes in powdered form was added to the mix followed by nutrients.The entire content was mixed thoroughly before being spread across the pit laid with a tarpaulin. The steps had to be followed for the entire quantity of sludge.

“It would normally take three months for the bacteria to eat up the hydrocarbons. We would be taking samples every month and test the levels of oil content till the sludge is completely oil-free and harmless,” Upreti said. IOC officials said they expected to treat another 150 tonnes of sludge in the coming days.

Coast Guard officials said they would need another 8-10 days to remove the remaining oil from the shore. On Saturday , a team began cleaning seawalls coated with oil by spraying chemical-mixed water.