The present invention is directed to methods of treating a hydrocarbon-containing waste stream to form a hydrocarbon-containing retentate and an aqueous permeate which is substantially free of hydrocarbon. The method includes passing the hydrocarbon-containing waste stream through a microporous membrane to yield the hydrocarbon-containing retentate and the aqueous permeate. The membrane comprisesa substantially hydrophobic, polymeric matrix and substantially hydrophilic, finely divided, particulate filler distributed throughout the matrix. The polymeric matrix has pores with a volume averagediameter less than 1.0 micron, and at least 50 percent of the pores have a mean diameter of less than 0.35 micron.