Ask the Expert Question-and-Answer Archive (Wastewater Treatment)

by Mike McGinness, EcoShield Environmental Systems, Inc.
June, 2003

Cleaning Oil and Grease From the Surface of Stainless Steel

Q. Im currently working on a project that involves cleaning oil and grease from the surface of stainless steel. It seems that using EPA Method 1664A is giving a false positive and detecting soap as oil and grease. Is there any alternative test method you suggest?

A. Have you considered that many soaps are a saponified (sodium hydroxide reacted with oil / grease) oil / grease? I can dig into this further (alternate EPA method) but using an alternate method may not make any difference in your final test results. Oil and grease is simply (perhaps too simply) defined as what ever is recovered by the lab method! If the soap attaches to and stays with the oil and grease particles throughout the test then it is considered oil and grease as well.