Microbial growth, or bugs, is a very serious problem. It starts with water and there is always some amount of water in diesel fuel storage systems from various sources such as;
• Vapor recovery, as part of the Clean Air Act, introduces water vapor into the fuel
• Condensation occurs due to temperature changes in the fuel storage tank
• The process to create ULSD uses water and some residual moisture remains
Microorganisms naturally occur in water. Water is the perfect habitat for the microorganisms (bugs) to thrive. Once the fuel is placed into a storage tank and sits idle, the water separates from the fuel. Without proper treatment, the bugs begin to grow and deteriorate the fuel leading to several problems outlined below.
How do the bugs grow?
Because there is water and a food source, the diesel fuel, fuel storage tanks are a perfect breeding ground for microorganisms (bugs). The bugs have an abundant food supply, they feed off the hydrocarbons in the fuel. The “rag layer” indicated below is the emulsion of water and fuel supporting the growth of the bugs. Once the bugs begin to grow they double in population every 20 minutes. As the bugs multiply they produce waste products. The waste products produce sludge, acids and other harmful by-products impacting the fuel and the storage tank. Eventually a black, brown or green slime will form clogging filters, corroding metal and causing hoses to swell and blister.