Lakes ravaged by oil spills saved by Russian expertise

Biologists have already lifted 157 tons of oil from the bottom of Lake Shchuchye, which was polluted by the Usinsky accident in 1994. Source: Lori / Legion-Media

Biologists have already lifted 157 tons of oil from the bottom of Lake Shchuchye, which was polluted by the Usinsky accident in 1994. Source: Lori / Legion-Media

Siberian scientists have developed new technology that can clean lakes polluted by oil spills, even in winter when temperatures fall as low as -50°C. This technology has given a new lease of life to Lake Shchuchye, which suffered a catastrophic oil pipeline accident in 1994.

Oil pipeline accidents ravaging large water bodies are a common problem in oil-producing areas across the world. The most popular water treatment techniques currently used are dredging and microbiological agents, both of which are expensive and labour intensive.

Researchers at Tomsk State University (TSU) in Siberia have pioneered a new and inexpensive technology that lifts oil from the bottom of a water body and pushes it to the water's surface during any season.

Biologists have lifted 157 tons of oil from the bottom of Lake Shchuchye, polluted by the Usinsky accident in 1994, when a decrepit pipeline spilled more than 100,000 tons of oil. The disaster was listed by the Guinness Book of Records as the worst environmental disaster of its kind.

"Attempts at a clean-up were made a few years after the accident, but it was not possible to return the ecosystem to its original state," biologist Daniil Vorobyov told RIR. "The vast majority of fish had severe congenital abnormalities."

No chemicals needed

The new method is based on the laws of physics and does not require the use of chemicals. A heavy hose is lowered to the bottom of a lake, and an air stream is pumped to an oil pocket. As a result, air bubbles push oil to the surface, where the spilt liquid is collected in floating pools filled with absorbents. This technique is best suited for lakes with rocky, clayey or sandy bottoms. Also, it reduces the concentration of harmful substances in the water to below dangerous levels. The scientists say that the method allows cleaning not only the bottom but also the entire lake. There are no limitations on the depth of water or the passage of time after an accident.

"Some accidents are not immediately known," said Vorobyov. "Oil sinks to the bottom of a body of water, killing many life forms and causing deformities in fish. We have created a technique that significantly reduces the consequences of oil pollution in virtually all bodies of water."

Cleaning under the ice

No technologies have existed until now to remove oil from frozen lakes at low cost. Siberian biologists, however, have found a solution. Channels that converge near oil collecting wells are made in the lake's ice covering. As with the "summer" technology, hoses are lowered through a hole to the bottom and then air is pumped in. In the frozen lake, however, the oil lifted from the bottom goes to a collector via these channels.

A mobile hangar is then installed over the collector where heaters create a favourable working temperature and the oil is removed. Ice-covered lakes can be cleaned of oil at any temperature, even at -50°C.

According to biologists, it is better to clean lakes in winter when ecosystem processes are slowed down or suspended. "Fish reproduction takes place in the spring and summer, so it is preferable to clean in the cold season," Vorobyov said.

In the case of Lake Shchuchye, the water purification experiment was a huge success, and the number of abnormalities in fish decreased by 98 percent. Life returned to the lake, and today mollusks, crustaceans and other organisms call it home.

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