MECHANISM OF MICROBIOLOGICAL CONTAMINATION OF JET FUEL AND DEVELOPMENT OF TECHNIQUES FOR DETECTION OF MICROBIOLOGICAL CONTAMINATION
Final technical rept., 1 Mar 1963-31 Jan 1966
MELPAR FALLS CHURCH VA
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The research was directed at developing rapid methods for detecting microorganisms in jet fuel water bottoms and at analyzing the chemical mechanisms by which microorganisms and other contaminants could cause operational difficulties in aircraft fuel systems. The mechanisms by which microorganisms produce emulsions, sludges, and fuel-soluble compounds and cause corrosion were studied. The ability of fuel isolates to produce emulsions was demonstrated, with jet fuel and pure hydrocarbons as substrates. The aldehyde and acid products of hydrocarbon oxidation, formed during the growth of the microorganisms, were believed to be responsible for some of the emulsions formed on jet fuel. Fuel oxidizing microorganisms were demonstrated to cause aluminum alloy corrosion by four different mechanisms 1 alteration of the ionic composition of the growth medium, 2 production of corrosive compounds, 3 deposition on metal surfaces and establishing oxygen and metal concentration cells, and 4 production of electron mediators which transfer electrons from the metals to electron acceptors in the microorganisms. During the first year of study, the growth medium was found to contain corrosion inhibitors and corrosion stimulators. Microorganisms were demonstrated to cause corrosion by removal of nitrate and phosphate as inhibitors. Nitrate was then tested for its ability to inhibit corrosion.