Fuel Tank Contamination: Why Water Is A Serious Problem, How To Test For It, And How To Remove It

Users of large fuel tanks need to recognize that special care should be provided for both the tank and its fuel. Many problems can arise for the user of poorly-maintained large fuel tanks, including expensive equipment damage. One of the most serious and common problems is water contamination of fuel. Below are a few reasons to help you understand why water is bad for fuel, tanks and equipment as well as information on how to test for and prevent water contamination:

Why water contamination is a problem

Water enters fuel tanks through leaks, hatches, valves, vents and condensation. "Bad" fuel from a supplier can also be contaminated with water when it is pumped into your tank. The presence of water inside of a fuel tank can cause serious damage both inside the tank itself and to the equipment that uses the fuel. Water can cause corrosion and rusting of tank interiors, ultimately leading to leaks and rust particle contamination of the fuel.

In addition, water contamination of fuel tanks can become the home to massive bacterial and algae colonies that consume carbon-based fuels as a food source. These microorganisms live in the water itself, but feed at the boundaries between water and fuel. They are harmful due to their creation of destructive wastes, such as slime, that ultimately clog filters and engine parts.

Testing for water contamination

Testing for water is an important step to take if you own or manage a large fuel tank. It should be performed with regularity to prevent a water contamination problem from getting worse or damaging your equipment. Here are a few test methods you can use to check for water:

• Frost formation test - Though it only works in cold weather, one simple, quick way to test for water is to look for frost formation on the exterior of the tank. Frost only occurs on tanks that contain water due to the temperature gradients involved. It is the only test that doesn't require sampling, but obvious drawbacks make it impractical to use during warmer months.
• Separometer test - A reliable, year-round method of testing fuel for water is to use a separometer, a portable device suitable for field work. Keep in mind that it is expensive, but if you want highly accurate test results, the separometer will provide them.
• Chemical test - another good alternative for checking fuel for water contamination is chemical testing; drops of a testing solution are placed into fuel samples, and depending on the reaction of the sample, you will be able to determine if it contains water or another contaminant such as alcohol.
• Layer test - fuel will float on top of water, so if you obtain a sample of fuel and pour it into a clear glass container, the water and fuel will separate into layers. The chief drawback to this test is that it takes several hours to permit complete settling and separation.

Keep the water out

Ideally, the best strategy is to keep water out of your fuel tank in the first place. Below are a few ways that you can prevent, or lessen, water contamination:

• Find a reliable supplier - if you have difficulty finding a reliable supplier of fuel, check with others who work in your business. Ask them to provide you with recommendations regarding suppliers. In most circumstances, a supplier who pumps a high volume of fuel is likely to have the least amount of water contamination, though always verify on a case-by-case basis that their fuel is free of moisture.
• Install a bulk fuel filter - adding a bulk fuel filter to your tank can also be beneficial in removing water from fuel. Just remember that filters should be checked and replaced on a regular basis.
• Check your tank for intrusion points - regularly inspecting your tank will help you catch any potential trouble spots. Defective valves and vents, and leaks in the tank or piping, should all be promptly repaired when discovered. Don't leave hatches open to the elements and shut all valves tightly after use.
• Use a fuel additive - there are several commercial fuel additives designed to neutralize water problems. They can capture the water molecules and bind them so they are unable to harm your equipment. However, always be sure to verify that a given additive is appropriate for your application and fuel type before adding it to your tank.

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