Efforts to clean oil spill stepped up

More nutrients are on their way to the city that will help fasten the degradation of oil-contaminated soil by microbes at Navy Nagar, the site that was most affected by the spill.

More nutrients are on their way to the city that will help fasten the degradation of oil-contaminated soil by microbes at Navy Nagar, the site that was most affected by the spill.

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On August 7, two ships collided off the city’s coast, spilling furnace oil and contaminating the Colaba coast and beaches in Alibag.

Since then, efforts are on to clean the beaches.

Dispatched by the Delhi-based The Energy and Resources Institute (TERI), the nutrients comprising carbon, nitrogen, phosphorus and trace minerals will be added to micro-organisms such as bacteria to break down the oil.

This is a process called bio-remediation that was entrusted to the institute last month by the state government.

The addition is following the institute's analysis that found oil content at Navy Nagar was at 3,81,000 ppm or parts per million — 381 times higher than the global permissible limit of 1,000 ppm - and will take at least four months for the oil to degrade.

“More nutrients are required because the oil content is very high or else the microbes won’t work effectively. The degradation will be very slow," said Banwari Lal, director for environment and industrial biotechnology at TERI.

“The nutrients will make the microbes more active,” he added.

Since the bio-remediation process on August 28, till date only about 18 per cent oil has degraded bringing the oil content down to 3,12,420ppm.

In contrast, bio-remediation for Awas beach in Alibaug where the oil content was 60 times higher has been effective. Of the 60,000 ppm found on the day of the spill, oil has degraded to 10,000ppm.

“It will take about 10 days to reach permissible limits and complete the bio-remediation process at Awas. The process has responded well here because the content was not as high as Navy Nagar,” said Lal.

Furnace oil is heavier and more difficult to degrade than crude oil because it contains organo-sulphur compounds that are highly undesirable from the environmental perspective.