QUANTIFICATION OF NAVY OILS IN DETERGENT LADEN WATERS

Abstract

ABSTRACT Accurate measurement of the concentration of oil in effluent discharged from ships is necessary so that water pollution regulations are not violated. Detergents used to clean machinery and deck surfaces aboard Navy ships often end up in bilge water and pass through gravitational and coalescence type oil/water separators. These detergents interfere in the solvent extraction and infrared (IR) spectrometry measurement technique for quantifying oil in water. They will absorb the IR energy at the wavelength used in quantifying oil; therefore, a method which can remove such interference, yet accurately measure the concentration of oil in water, is needed. A technique of eluting the solvent extract through silica gel removed most of this interference. Aqueous samples containing Navy oils and a non-ionic detergent in concentrations up to 1000 milligrams per liter were used to evaluate this technique. The solvent extract of these aqueous samples was filtered through silica gel and the IR absorbance of the effluent at 2,930 reciprocal centimeters was measured. The results demonstrated that this technique can yield the true concentration of oil in detergent laden water as long as the ratio of the concentration of detergent to oil is less than 10 to one. This technique can also be applied to quantify oil in water that does not contain detergent.