Patent ID: 7807059

Claim:
A cyclical method for collecting pollutants having a density lower than that of water and carried by a surface layer of a body of water, in which: in an intake phase of a cycle of operation, water of the surface layer is caused to flow into and through a collection vessel having a separation compartment with a top wall, pollutants entrained by the inflowing surface layer water are allowed to collect gravimetrically as a supernatant layer carried beneath the top wall of the separation compartment on water in the separation compartment, during a discharge phase of the cycle of operation, the layer of pollutants collected beneath the top wall of the separation compartment is dispelled from the separation compartment through a riser outlet communicating with the separation compartment by means of displacing water introduced into the separation compartment beneath the supernatant layer, wherein the changes of the weight of the collection vessel in the body of water are monitored during the cycle of operation by directly weighing the collection vessel in the body of water in which the weighing of the collection vessel is made by one or more load cells, and the intake and discharge phases are initiated and terminated in response to the said weight reaching predetermined values.