Patent ID: 6048461
Filing Date: 2000-04-11
Classification: B01D,Y10S

Abstract:
A method of extracting oil from oil-contaminated water, including spillage water from gasoline stations and water that emanates from vehicle-washing plants, said method comprising the steps of: passing oil-contaminated water from a source of oil-contaminated water through a collection filter in which oil and coarse particles are collected in a first cleansing stage; passing filtered water from the collecting filter through a fine filter to lower the oil content of the water to a level below approximately 50-75 mg/l in a second cleansing stage, wherein the fine filter includes a mass based on sawdust that has been treated to render the mass hydrophobic so that the mass is able to absorb petroleum products without taking-up any appreciable amount of water, and wherein contaminated water is caused to pass through the mass; passing treated water from the fine filter to flow through a first membrane filter to filter-off at least 75% of the oil remaining in the water in a third cleansing stage; and recycling at least a part of at least the water cleansed in the membrane filter back to the source of the oil-contaminated water; and discharging a residual part of said water from the third cleansing stage to a municipal sewage network.