An oil film is usually collected from the water surface by the following method: granules with good absorption properties are poured into the water. After they have taken up as much water as possible, they are collected with a special transporter.
The problem is that the collecting process is inefficient because a great number of granules fall into the water again. There exists a good solution to this problem: iron filings are added to granules and then removed by a magnetized transporter. And inventors from Volgograd – Zheltobryukhov, Koblov and Efanov – proposed an oil-collecting method that eliminates the problem of granules at all (Patent of Russia No. 2148025). Oil is collected not in the form of granules, but as a continuous carpet. The carpet consists of fibrous cellulose material and rubber crumb (apropos the crumb may be produced from used tires – an additional ecological advantage).

Many separate granules merge to form a continuous carpet that performs the same function: a polysystem turns into a monosystem at a new level, the previous function being preserved. 
 

Information source: the magazine “Technics for young people”.