What Is Diesel Fuel Contamination? [Types, Causes & Signs]

Diesel fuel contamination, as the name suggests, is the presence of unwanted substances in diesel fuel, including water, microbes, foreign materials, or fuel additives. Contamination can happen at any point in the fuel supply chain, from the refinery to the end-user.

Wherever diesel contamination occurs, it negatively affects the quality, performance, and performance of diesel engines. It can happen for many reasons, has many types, and effects wherever it’s used. Be with me as I’ll uncover everything in this guide!

Diesel Fuel Contamination
Signs of Diesel Fuel Contamination

Signs of Diesel Fuel Contamination

As I told you earlier, diesel fuel contamination can occur for many reasons. It could be due to water, fuel additives, and the list goes on. But the real question remains: how do I know that my diesel fuel is contaminated? The following are the signs of contaminated diesel fuel.

  • Water Contamination in the Oil
  • Microbial Contamination in the Fuel
  • Eroded Fuel Tank
  • Engine or Equipment Problems

Most Common Types of Diesel Fuel Contamination

Water Contamination

Water contamination in oil is the most common type of diesel contamination. Water can enter fuel through condensation, rainwater penetration, or faulty seals and react with the diesel, contaminating it. The issue of water in diesel fuel contamination occurs at many different levels.

In the early stages, water contamination exists as tiny particles in the air that cannot be seen without special tools. As more water accumulates in the tank, it mixes with the emulsifiers and oil. At this stage, you might see water droplets in the oil, making the fuel look cloudy.

Once the early stage passes, small pools of water will ultimately collect at the bottom of the tank. Well, you might have controlled the issue at the very first stage if professionals have regularly tested your fuel. Even at this stage, looking at the top of the tank won’t reveal this issue.

Ultimately, bacteria can grow rapidly when the water separates from the oil and becomes free-flowing at the bottom of the tanks. This can lead to the formation of organisms, which is known as microbial contamination—another severe type of diesel contamination.

Microbial Contamination

Microbial fuel contamination is caused by the growth of microorganisms, such as bacteria and fungi, in diesel fuel. These tiny living organisms are everywhere, including in the air and on surfaces. They can easily enter fuel during its transportation and storage.

Certain types of microorganisms that thrive in the presence of oxygen, which they obtain from water, can cause damage to fuel systems. These microorganisms feed on the hydrocarbons present in the fuel. If there is water present in your stored diesel, chances are it will be a home of microbes.

Even a small amount of water, like a single droplet, is enough for microbial contamination to occur and persist in diesel fuel. These microorganisms can grow within fuel systems, and warmer conditions can accelerate their growth along with higher humidity levels.

Particulate Contamination

Sediment and particulate matter in diesel fuel can result from poor filtration during production and debris and contaminants introduced during storage and transportation.

Sediment can settle at the bottom of fuel tanks and get drawn into the fuel system, leading to fuel filter blockages, clogged injectors, and abrasive wear on engine components. Particulate matter can also contribute to increased emissions and decreased fuel efficiency.

Why Does a Fuel Tank Erode?

When microbial fuel contamination becomes severe, it starts eroding the fuel tank. During the worsening contamination, the microorganisms present in the fuel begin to consume the tank material, causing erosion. This is one of the clear diesel bug symptoms of fuel contamination, indicating you should opt for diesel bug treatment.

How to Tell If Your Fuel Is Contaminated?

To see if your diesel fuel has microbial contamination, watch out for these main signs:

  1. Water mixed with the oil.
  2. Fuel tank is showing signs of erosion or damage.
  3. Presence of a bug or microorganisms in the fuel.
  4. Problems with your engine or equipment.

What Are the Effects of Diesel Fuel Contamination?

Suppose you haven’t checked the diesel fuel in the container and put it into your vehicle’s fuel tank. In such a case, when you’ll start the engine and/or drive toward your destination, chances are you will see a few of the following effects of contaminated fuel.

Incorrect fuel level readings

Contaminants can form a slimy layer called biofilm, which can coat tank fuel quantity systems. This can cause problems with the fuel level probes, leading to inaccurate readings.

Poor engine performance or total failure

Contamination can block fuel filters, resulting in reduced engine performance. This can result in reduced fuel economy and higher emissions. In severe cases, if the fuel filter is completely blocked, the engine may stop working altogether.

Injector malfunction

Injectors, which are part of more advanced engine systems, are prone to malfunction when they become clogged with contaminants. This can disrupt fuel spray patterns and negatively impact engine performance.

Make the transition from fossil fuels to cleaner burning alternatives such as HVO fuel
Common Types of Diesel Fuel Contamination
Effects of Diesel Fuel Contamination

How to Test Contaminated Diesel Fuel?

Colony Forming Unit (CFU) Testing

CFU tests are conducted in laboratories; it usually takes 4-10 days to get the inspection results. Although these are the most authentic ones, they can be expensive and challenging due to handling, transport, and laboratory costs.

These tests aim to determine the level of microbial presence in a fuel sample by growing and counting the microbes in an incubator. CFU tests are authentic to inspect your fuel tank, but they don’t specifically target the microbes that cause damage to fuel systems.

ATP Testing

ATP (Adenosine Triphosphate) testing can be done on-site and provides results within minutes. It requires a specialised device called a luminometer. But these results aren’t as authentic as for CFU testing.

ATP testing detects total microbiological presence, including non-damaging microbes. This broader scope may lead to misleading results.

Additionally, conducting ATP testing in a different location from the fuel storage or usage area can introduce external microorganisms, affecting the accuracy of results.

Immunoassay Antibody Tests

Immunoassay antibody testing is the latest technology for witnessing diesel fuel contamination. It involves a simple ‘add drops and wait’ process, like a pregnancy test.

This method is fast, typically providing results within 10-15 minutes. Immunoassay antibody tests specifically target harmful microbes in diesel fuel.

They can be performed without complicated equipment, sterile conditions, or specialised training. The tests can be conducted wherever the fuel is stored, making them convenient and accessible.

How to Manage Fuel Contamination Throughout the Year?

In Winter

Switch to Winter-Grade Fuel

Regular diesel fuel can form wax crystals that clog filters and fuel lines as temperatures drop during winter, causing engine failure.

To prevent this, switch to winter-grade fuel before the cold season arrives. Winter-grade fuel contains additives that prevent the formation of wax crystals, allowing it to flow smoothly in freezing temperatures.

Regularly Remove Snow from Plastic Tanks

Heavy snow can put stress on plastic fuel tanks, potentially causing splits, cracks, or weak points in the tank’s walls. To protect your tank, shelter your tank or remove large snow deposits from the top.

Lagging or insulating exposed pipework can also prevent freezing damage and minimise condensation build-up inside the tank.

Position Your Tank Securely

Strong winds can rev heat loss from a fuel tank, causing immediate cooling of the stored fuel. Additionally, as fuel levels drop, the tank becomes lighter and more susceptible to being moved by strong winds, potentially leading to tank damage and oil spills.

Therefore, check that your tank is securely positioned on a level and stable base before winter arrives. Keeping your fuel tank topped up also helps to maintain its position and stability.

Check for Any Damages and Any Openings

Rainwater can enter your fuel tank through corroded or faulty seals, damaged vents, or compromised tank integrity due to cracks or holes.

This creates a perfect environment for diesel bugs, microorganisms that thrive in the presence of water and quickly multiply, leaving behind a waxy sludge or biomass.

Regular tank inspections and ensuring caps and hatches are properly closed can help prevent water ingress and fuel contamination.

In Spring

Check Your Fuel for Sludge and Residue Build-Up

After a winter of using your fuel for heating and equipment, sludge and residue can accumulate in the fuel tank. If left untreated, these contaminants can cause intense harm to your fuel equipment and system. Regular maintenance and tank cleaning in spring can help avoid such issues.

Be Aware of The Fluctuating Temperatures

During spring, the fluctuation between cool nights and warm days can cause condensation to form inside the fuel tank. The water droplets that settle at the bottom of the tank create an ideal environment for diesel bugs and other harmful contaminants to thrive.

These microorganisms degrade the fuel quality, leading to sludge build-up and potential damage to your engine. Regular professional fuel tests can help identify condensation and diesel bug growth.

Look for Corrosions Caused by Heat and UV Light

While steel tanks are sturdy and durable, they are also susceptible to corrosion caused by heat and UV light. Over time, corrosion weakens the tank’s structure, leading to cracks and holes that can result in oil spills and environmental damage. Regular fuel tests and tank cleaning by professionals can help detect and prevent tank corrosion.

How to Prevent Fuel Contamination?

Taking good care of your stored fuel and getting it checked by professionals regularly is very important. By being proactive and planning ahead with maintenance, you can prevent contamination issues and avoid expensive emergency situations.

Network Environmental UK offers fuel testing and industrial tank cleaning services. This means we can provide a complete solution to keep your business fuel in top condition and protect it from potential problems. Contact our team to get your fuel checked!

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