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Microbiological Contamination Detection Sensor for Fuel Storage Tanks



OBJECTIVE: Develop and demonstrate an in-line and in-tank (permanently or temporarily resides within the confines of the fuel storage tank) sensor to provide fuel tank managers early detection of the presence of microbial contamination in aviation or ground fuel storage tanks to allow corrective actions to be executed. 

DESCRIPTION: Air Force installations that store and issue alternative bio-based fuels such as biodiesel or Ultra Low Sulfur diesel (ULSD) fuel have an increased requirement for tank cleaning due to bioaccumulation from microbial contamination. Tank cleaning maintenance actions cost an estimated $15,000 per event, per tank for ground fuels. Microbially contaminated fuel is generally required to be disposed of due to its unsuitability for use, costing an estimated $5.00 per gallon for disposal, not including the cost of replacement fuel. Traditional tank cleaning methods have historically not completely sterilized a tank after cleaning. As a result the remaining microbial biofilms will generally re-contaminate the tank within 12-18 months. Current test methods to determine microbial contamination are either required to be run in dedicated laboratories where samples must be submitted under controlled conditions or run in the field with limited success and detail. Additionally they do not provide continuous monitoring of tank inventories and readings vary greatly depending upon where in the tank a sample was taken (bottom fuel, bottom water, mid-level fuel). Further, buildup of bioaccumulation results in microbial induced corrosion (MIC). MIC causes physical deterioration of fuel storage tanks which results in higher operations and maintenance costs associated with repair, monitoring, and potential environment impact from leaks. Development of an electronic sensor able to detect microbial contamination in its early stages (and distinguish it from other particulate manner) needs to be developed for installation in fuel storage tanks. The sensor must provide a continuous monitoring capability and provide notification when contamination is first identified so early preventative steps can be taken to prevent spreading of the contamination to equipment or vehicles. The sensor will not require a laboratory trained technician to operate. It must be able to function within all current aviation turbine and diesel fuels grades handled and operated by the US. Air Force world-wide. The sensor must be capable of being integrated into all known and future fuel storage and hydrant system configurations operated by the US Air Force. The sensor must be able to operate as a standalone system or integrate into existing automated tank management systems. 

PHASE I: Feasibility Study: Develop an approach for the design of an in-line and/or in-tank sensor capable of early detection and identifying of microbial contamination within existing and future US Air Force aviation/ground fuels storage tanks for all grades of aviation turbine and diesel fuels. Conduct proof of principle experiments supporting the concept and provide evidence of the feasibility of the approach. Sensor technologies shall be able to detect a broad spectrum of microorganisms associated with fuel biodegradation, fuel biofouling, and bio-corrosion including bacteria (i.e., Gram negative and Gram positive), filamentous fungi, yeasts, sulfate-reducing bacteria, and archaea. Methods focusing on detection of a single microorganism or a limited group of microbes are discouraged. Sensors based technologies that prevent the risk of fire are desirable. Proponents should characterize the appropriate sensor location that improves detection and sensitivity in the fuel system (e.g., the fuel, the fuel-water interface, or the aqueous bottom). 

PHASE II: Phase II Full Research and Development Effort: Develop, build, and evaluate two prototype microbial contamination sensors (one of an in-line configuration and one of a in-tank configuration) meeting the requirements provided in the description of this SBIR topic and other requirements provided by the Air Force. The Phase II final report will document the results and provide transition plans needed to implement into production capability. 

PHASE III: Technology developed under this SBIR could have an impact on aviation or ground fuel storage. The intended transition path being into the installation in all Air Force aviation and ground fuel storage tanks to monitor and allow early intervention on microbiologically contaminated fuel storage tanks. The development of this technology will also have a 50% or greater emphasis on applications in the commercial fuel storage tanks or in commercial fuel analysis. 


1: An Assessment of Alternative Diesel Fuels: Microbiological Contamination and Corrosion Under Storage Conditions

2:  U.S. Army and Department of Defense Experience with the Use of B20 and other Biodiesel Blends

3: Microbiological and Corrosivity Characterizations of Biodiesels and Advanced Diesel Fuels

4: An Analysis of Microbial Contamination in Military Aviation Fuel Systems

KEYWORDS: Aviation Turbine Fuel, Microbial Contamination, Sensor, Bio-diesel Diesel, Fuel Storage Tank 


Gordon Walker (AFPET/PTPS) 

(937) 255-8017 

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