Cleaning up the mess off Chennai coast

The latest oil spill in the Chennai coast where two ships - BW Maple of UK and Dawn Kanchipuram of India - collided on January 28 resulting in spilling of 100 tonne of oil is the second such incident happening following collision of ships.

The previous one was in the Mumbai coast as vessels MV MSC Chitra and MV Khalijia collided on August  7, 2010. The spillage was huge – 800 tonnes.  The other major incidents in India include: On December 9, 2016, 300 tonnes of oil spilled into the sea at Sundarbans (and in Bangladesh) from ship OT Southern Star 7. On January 21, 2011, 55 tonnes of oil got released into the sea as the Mumbai Uran pipeline broke.

The hydrocarbon sector worldwide has been undergoing drastic changes leading to increased industrial activities in the area of hydrocarbon processing. In general, the long-term oil exploration, production, transportation, storage, refinery processes and use of different petroleum derivatives creates widespread contamination of environment by generated oil spills and oily sludge in around the facilities of petroleum industry.

Nowadays, spills of crude oils and fuel oils during transportation in tankers, freighters, pipelines through either land or water, capture public attention. This would further increase the demand to treat them by any physical, chemical and biological methods which includes thermal incineration, solidification, solvent extraction, ultrasonic treatment, photo-catalysis, pyrolysis and bioremediation.

Oil spills are manmade or accidental disasters and might be dangerous for any marine ecosystem which can affect any marine animals and plants in two ways, either from the oils or from clean-up operations. Spilled oil can damage any living habitat because of the complex chemical constituents including polycyclic aromatic hydrocarbons and thousands of other molecular species.

These molecular species are often grouped into four categories: saturated hydrocarbons, aromatic hydrocarbons, resins, asphaltenes. These compounds are highly hazardous causing skin erythema, skin cancer, sino-nasal cancer, gastrointestinal cancer and bladder cancer in humans and smother some small species of fish or invertebrates and coat feathers and fur, reducing the population of birds and mammals. Oil spills could also impact on sea turtles, mangroves and coral reefs.

There are different methodologies that can be adopted for the purpose of cleaning up oil spills. Oil boom based clean-up is more popular for controlling oil spills. Apart from that, sorbent based clean up, in situ burning of oil, dispenser based method, skimming, hot water spraying, manual removal by manpower, heavy earthwork equipment-based removal are the common practices to tackle this crisis.

The containment booms are temporary floating barrier to capture spilled oil and store in a barricaded area. Booms are used to reduce the possibility of further contamination of shorelines and adjacent resources and easy access for recovery of the contaminants. Booms could help concentrate oils and make a thicker surface layer so that skimmers, vacuums or other collection methods will be effective.

Booming tactics are of several types including containment booming, diversion booming, deflection booming and exclusion booming depending on the storage requirement. If oil reaches a shoreline, biodegradation can be stimulated by carefully delivering biologically available nitrogen and phosphorus to at least partially reduce their limitation on microbial growth.

The other approach is bio-augmentation which aims to add exogenous cultures which will jump-start biodegradation. In India, The Energy and Resources Institute (Teri) and Indian Oil Corporation Limited (IOCL) are pioneers in the development and application of the bioremediation processes.

Indian coastline is 7,500 km long where this crisis is not much prominent and only very few incidents have been reported till date in the Arabian Sea. Last month, a massive clean-up operation was launched in Tiruvallur, Chennai and Kancheepuram districts after two shipping vessels collided outside the Kamarajar Port, Chennai, resulting in rupture in one of the vessels which led to an oil spill.

This incident is considered the third major one near the Indian coastlines. This clean-up operation was launched by engaging more than 2,000 local people at various locations including Ernavur, Chennai Fishing Harbour, Marina Beach, Besant Nagar, Kottivakkam, Palavakkam, Neelankarai and Injambakkam beaches.

The Indian Coast Guard (ICG) jointly coordinated this operation with personnel of Chennai and Kamarajar Port. The IOCL, local NGOs, cadet trainees from maritime educational institutions and fisherman took part in these massive clean-up operations. Super suckers and submersible pumps were used for removal of oil from spill. The ICG, which sprayed oil spill dispersant for removal of oil slicks, is further involved in monitoring of the situation through ships and chopper.

Oilzapper technology

The Teri’s customised Oilzapper technology could be beneficial in this by employing naturally occurring micro-organisms to accelerate the degradation of oil and residual sludge of approximately 90 tonnes which were removed from spilled locations. After extensive research, Teri and IOCL have jointly developed Oilzapper technology – a crude oil and oily sludge degrading microbial consortium formulation derived from five naturally occurring micro-organisms.

These bacteria could be multiplied under laboratory conditions followed by mixing with carrier material and ready for transportation to the site of spills using reusable polybags. This technology has already been tested in India and other countries across the globe since last more than 15 years to tackle oil spills and sludge contamination.

The Indian oil companies are continuously using this technology to treat the sludge and recently the Kuwait Oil Company  recycled their huge volume of sludge and contaminated soil through our technology. Very soon, the Teri will complete this project.

The Chennai oil spill has been well-tackled by individuals and different organisations where everyone took active participation for removal of the spill. The Indian Oil Corporation provided special bioremediation material to treat the spill which is very encouraging. Other measures used in this clean-up operation would not be sufficient for complete restoration from oil spill. Six months to one year is required for clean-up of the spills in the Chennai coast through bioremediation and definitely the affected sea and adjoining shoreline could be restored to the original.

It is always recommended that pollution response equipment should be employed to all major ports and a dedicated team must be formed after inducted with advance training and acquisition of equipment for safe handling of the accidents.

(The writer is Senior Director, The Energy and Resources Institute, New Delhi)

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