Occurrence of heterotrophic bacteria and fungi in an aviation fuel handling system and its relationship with fuel fouling.
Clean, dry and contaminant-free fuel is necessary for safe and economical aircraft operation. Microbial growth in aviation fuel handling systems can alter the quality of the product. This paper reports the occurrence of heterotrophic bacteria and fungi in a handling system of jet A-1 aviation turbine fuel. A total of 350 samples were collected during 1990-1996. The aerobic microorganisms in fuel samples were mainly fungi, 85% of samples containing < or = 100 cfu/l (range 0 (< 1 cfu/l) to 2000 cfu/l). The predominant fungi were Cladosporium and Aspergillus. Water was observed mainly in samples extracted from the drainage pipes of two tanks used frequently as intermediate storage tanks. The aerobic heterotrophic microorganisms found in water samples were mostly bacteria, counts varying from 100 to 8.8 x 10(7) cfu/ml, with 85% of samples containing 10(4)-10(7) cfu/ml. There was a preponderance of Pseudomonas spp. Bacterial contaminants belonging to the genus Flavobacterium and Aeromonas were also identified. Sulphate reducing bacteria were detected in 80% of water samples. It was not possible to assign a maximum microbial contamination level above which maintenance is required and it is suggested that analysis of successive samples from the same site are necessary for this purpose. Microbial sludges produced in the laboratory and collected from a contaminated tank bottom were analysed chemically. The data are presented and discussed. Samples collected from the supply pipes of tanks and refueller trucks during the period surveyed always met the standard specifications.
Ferrari
M D
MD
Centro de Investigaciones Tecnológicas, Administración Nacional de Combustibles, Alcohol y Portland (ANCAP), Pando, Canelones, Uruguay. dferrari@fing.edu.uy
Neirotti
E
E
Albornoz
C
C
D000333:Aeromonas / Q000302:isolation & purification; D000401:Aircraft; D001230:Aspergillus / Q000302:isolation & purification; D001420:Bacteria, Aerobic / Q000302:isolation & purification*; D002963:Cladosporium / Q000302:isolation & purification; D004866:Equipment Contamination; D005417:Flavobacterium / Q000302:isolation & purification; D005648:Fuel Oils / Q000382:microbiology*; D005658:Fungi / Q000302:isolation & purification*; D011549:Pseudomonas / Q000302:isolation & purification; D013818:Thermogravimetry
D005648:Fuel Oils