EVALUATION OF A BIOCIDAL TURBINE-FUEL ADDITIVE

Growth of microorganisms in water-contaminated, kerosene-type fuels is a widespread problem in aviation. One approach to the solution of this problem is the introduction into fuel of a chemical additive which could stop or retard growth of microbes. Evaluation of the effectiveness of such an additive was conducted in the laboratory under conditions which approximated field operations. Organisms of known identity and isolates from contaminated fuel, when cultured in aqueous nutrient media, responded vairably to the additive; however, most fungi and bacteria were severely inhibited by 1,000-5,000 ppm. In simulated fuel cells containing turbine fuel and an aqueous solution of inorganic salts, all fungi were killed within four days at 270 ppm additive. The effect on bacteria in this system was negligible, an observation supported by a three-month field test in a Convair 880 aircraft where 270 ppm in fuel caused an almost complete disappearance of fungi with little effect on bacteria. Tests also showed that while microbes remain viable in dry fuel, they require a discrete water phase for multiplication. (Author)