Effect of moisture content on the microbial activity in JP-5 fuel oil

The water solubility of JP-5 fuel oil was found to be proportional to the reciprocal of absolute temperature from 0 degree C to 60 degrees C. Water in the fuel oil would become condensed once the temperature was shifted from a high temperature to low temperature. During the storage, condensed water was precipitated in the bottom of the tank. Both the static and the dynamic dehumidification processes with molecular sieve could reduce the moisture content of fuel oil to less than 5 ppm. However, pre-dried fuel oil had a mildly hydroscopic phenomenon at relatively high humidity condition. The spores of contaminated microbes could survive in the fuel oil with 5 to 80 ppm of moisture content. High moisture content of fuel oil was not favorable to the spore survival. Penicillium sp. could survive in the fuel oil longer than Cladosporium resinae.