U.S. Navy Ship Salvage Manual Volume 6 - Oil Spill Response

S0300-A6-MAN-060Recovery efficiency increases with oil layer depth for all recovery methods. The sooner oil recoverystarts after a spill, the less the oil has spread and the more efficient the recovery. Whereverpossible, oil should be contained or collected to thicken the oil layer and enhance recovery, aswell as to protect the environment.5-2.1 Oleophilic Devices. Oil is removed from the water by oleophilic devices when oil adheresto moving oleophilic belts, ropes, drums, disks or brushes. The oil is subsequently scraped, wrungor squeezed from the material for collection in a receptacle. The oil is diverted to a holding sumpuntil it is offloaded. Oil recovered with oleophilic materials can have a water content of less thantwo percent, but the water content depends upon many factors, including the operator and theenvironment.Cold can cause certain oils to adhere to the oleophilic material so strongly that they cannot bereadily scraped or squeezed into the reservoir. Under these conditions, steam lances and solventsenhance removal of the oil from ropes and belts.Dispersants reduce the efficiency of oleophilic materials. Oleophilic materials exposed to dispersantsshould be cleaned thoroughly before reuse.5-2.1.1 Belt Skimmers. Belt skimmers use an endless belt running continuously through the oillayer as shown in Figure 5-1. The belt may or may not be oleophilic. Belt systems may be permanentlyinstalled on either self-propelled vessels or on nonself-propelled units operated from a pieror vessel.Figure 5-1. Belt-Type Skimmer System.5-3