Slick move

Greek researchers have developed a new system for lifting oil slicks from the sea’s surface. However, industry experts are sceptical.

Greek researchers have developed a new system for lifting oil slicks from the sea’s surface. The technology is designed to cope with slicks such as the one caused by the spill from the tanker Prestige, which sank this week off Northern Spain.

The Hellenic Innovation Relay Centre in Athens has unveiled CleanMag, a porous, non-toxic granular co-polymer with magnetic properties that absorbs oil when it is sprinkled on a sea-borne slick.

CleanMag has a density lower than water and so remains on the surface after application. Once the oil is absorbed, the material can be collected by vessels equipped with electromagnets or magnetic drum conveyor belts. Afterwards, CleanMag can be separated from the hydrocarbons and recycled, so the recovered oil can continue to the refinery for use.

However, industry experts are sceptical of these claims. ‘The possibility sounds wonderful, but its effectiveness depends on the amount of material that needs to be added,’ said Dr. Paul Kingston, a marine biologist at Edinburgh’s Heriot-Watt University.

‘Previous systems depending on the addition of a polymer to the oil have proved to be too expensive for use on a large scale.’

As The Engineer went to press, clean-up vessels were attempting to deploy booms to contain the slick from the Prestige. However, these are far from effective.

‘Containment using booms is a bit of a PR exercise,’ said James Allen-Jones, technical director at Scottish firm Slysar.

‘They can only be moved at a speed of one knot, but it is hard to control the ships dragging them at this speed. Any faster and oil goes under the boom. Even if the weather is ideal, they do not recover more than 10 per cent of oil spilled.’

With the help of NESTA funding, Slysar has developed an inflatable boom system designed to allow recovery and retention of spilled oil at speeds of up to five knots, collecting a minimum of 50 per cent of the spill at five times the speed.

Using two tugs dragging either end of a narrow-mouthed U-shaped structure oil and water is swept into the device. After passing over the apex of the U, which is submerged, it enters a lagoon formed from another set of booms, but with a solid floor. A series of vents at the rear of the structure lets clean water escape while retaining the oil.

Elsewhere, the European Nimasco Group has developed a biocatalytic process that accelerates the natural biodegradation process.

Although the oceans contain over 20 micro-organisms that break down the polymeric chains in oil, reducing it to carbon dioxide and water, this can take months.

But by adding naturally occurring nutrients, vitamins and bio-stimulants, the Eco-Bio process can break down crude oil in under a day. However, the disadvantage of this method is that the tanker’s cargo is lost.