Got Diesel Bugs in Your Fuel? How to Fix the Problem
Diesel Bug or Diesel Algae?
Diesel bugs — also called diesel algae — might be the reason you have contaminated fuel in your bulk fuel storage tank.
To most people they mean the same thing, but it’s neither insects nor algae.
True algae, such as seaweed, is an aquatic plant that transforms light into energy. Diesel storage tanks, however, shield fuel from sunlight. Algae can’t grow or survive in dark fuel storage tanks.
Call it what you like — diesel bugs, diesel algae, diesel slime, diesel bacteria — but technically, it’s microbial poop, and it piles up in tanks.
Bacteria, mold and fungus grow in diesel fuel tanks when three conditions are present: water, air and the right hot, humid environment. These microbes feed off hydrocarbons in the fuel and excrete waste.
Diesel Bug Symptoms in Fuel Storage Tanks
The three big things to look out for are:
- Change in fuel color
The bigger the change in color from the original fuel source, the more concentrated the contamination from microbes.
- Change in fuel consistency
If fuel is “denser” in consistency and leaves a slimy residue on surfaces, fuel contamination already has happened.
- Sludge in the bottom of the tank
When diesel microbe waste builds up on the bottom of diesel fuel tanks, a thick sludge forms, said John Higginbotham, general manager of B&B Oil Co. He’s seen the effects of diesel bugs during his 30 years in the fueling business.
“The bottom of that tank you could probably clean with a shovel,” Higginbotham said.
Diesel Bug Symptoms in Vehicles
Diesel bug symptoms include sludge that gums up fuel filters, corrodes equipment and damages engines. It also leaves a slimy coating on fuel lines and slows fuel flow.
But diesel bugs aren’t always that obvious. That’s why testing and maintenance are important. Symptoms become more obvious as diesel bug contamination worsens. When this happens, symptoms extend from fuel storage tanks and fuel systems to vehicles.
- Blocked filters
- Clogged injectors
- Fuel gauging system problems
- Corroded fuel systems
- Fuel tank leaks from corrosion
- Increased fuel consumption
- Poor engine performance
- Engine failure
Prevention
Prevention is the easiest, most cost-effective way to deal with diesel bugs. These steps can help prevent microbes from contaminating your diesel fuel storage tanks.
- Keep your tank full. (A full tank means less air.)
- Regularly remove all water from storage tanks.
- Test your diesel fuel monthly.
- Clean your diesel fuel tanks annually.
- Perform regular diesel tank inspections, maintenance and repairs.
- Take immediate action on contaminated diesel tanks, unless you want the problem to get worse and you want to spend more money.
- Do not deviate from standard operating procedures.
Diesel Biocide
Diesel biocide is made to kill diesel microbes. This fuel treatment is the most common way to solve moderate to severe microbial fuel contamination, but it also introduces risks.
One risk with using biocides is “maintenance dosing,” which uses several sub-lethal doses that create super microbes resistant to biocides. It happens with antibiotics and bacterial infections in humans, and it happens with biocides and diesel bugs in storage tanks. A better way is to shock the contaminated tank with a high dose of biocide and follow up with subsequent, planned “kill doses” as preemptive strikes.
Then again, another risk with using biocides is tank corrosion. Use biocides as infrequently as possible.
Fuel Polishing
Fuel polishing is expensive and involves several rounds of advanced filtration. Fuel polishing, unlike biocides that kill microbes but leave dead microbes in the fuel, removes the microbes and their waste so they don’t turn into sludge. Usually fuel polishing is reserved for the most severe cases of microbial contamination.
Fuel Tank Cleaning
Fuel contamination testing determines how a fuel tank needs to be cleaned and treated, depending on contaminants and severity. Experts recommend annual cleaning, which helps prevent tank corrosion and extends tank life. A complete tank cleaning can be expensive and lead to downtime for the tank.
Fuel Write-Off
This is the last choice a fuel owner wants to make, but sometimes diesel fuel gets so contaminated with diesel bugs and degraded that it is unusable. It can happen to diesel fuel in bulk storage and in idle equipment. When diesel bugs form colonies, acid, rust, corrosion and filter plugging aren’t far behind. Then, it’s too late to save the fuel and the equipment. The problem is a complete loss.
More Resources
Fuel Contamination Happens — So Prevent it Now
Need Help? Ask the Experts
For help in choosing the right small diesel storage tanks and large diesel storage tanks, it makes sense to ask the experts. Unity Fuel Solutions is North America’s leader in double walled storage tanks. For advice on the tank and system that’s right for you, call the Unity team at 800-234-1689.