Microbes could be multiplying in your diesel fuel system right now, or maybe you’re here because you’ve already found them and the problems they’ve caused!
“So what” you might say, why should I care?
Microbes could be getting ready to overwhelm your fuel system, blocking your fuel filters and shutting down your engines, which unfortunately for you, may occur at the most inopportune time.
Once stripped down, worst case scenario, if you’ve had the problem for some time you could find your fuel lines and tanks are damaged beyond repair with pitting and corrosion caused by the action of the microbes under the carpet of bacteria and fungal biomass. A silent, but potentially very expensive, not to mention dangerous, invasion!
Your next reasonable question is likely to be:
Why now? I’ve never had a problem before?
Due to emission regulations and green initiatives, governments and fuel companies have started to introduce lower sulphur levels (ULSD – ultra low sulphur diesel) and biofuels into the fuel stocks. The drawback is that microbial growth, while not a major problem in the past, has now become a real issue with these blended fuels.
Biodiesels are hydroscopic and therefore attract higher levels of water/moisture. While on its own reduced levels of sulphur have little affect, the combination of the two is believed, by some in the industry, to be a major factor behind the increasing incidence of microbial contamination around the world. With the added nutrients available in biofuels it’s not surprising that growth rates have increased considerably. Hearsay evidence suggests even cross contamination during transportation of these fuels can lead to higher levels of microbial contamination in stocks of standard diesel.
The next logical question is:
What should I do about the problem?
The first thing to do is to take a sample from your tank and test the fuel to see if you have a problem, and if so, how bad it is. The next stage is to kill any microbes detected by treating the fuel with an appropriate treatment option i.e. biocides etc. This may also include draining of the tank, a tank entry and physical cleaning of the tank surfaces and associated pipework to remove the biomass, before refilling the tank and introducing a shock dose of biocide to kill off any remaining microbes.
From then on, best practice is to introduce a fuel cleanliness program, including testing as a regular part of your maintenance schedule. Often pre-winterisation is chosen as the test point. A bi-yearly test is usually sufficient unless you refuel frequently in hot humid areas and/or from fuel sources of dubious quality. Therefore testing as often as every 3 months may be required.
Testing of the fuel before purchase is also advisable, particularly where the uplift of large volumes is involved. The KEY FACTOR in keeping the bugs at bay is regular draining of all water from the fuel tank/s. This means getting rid of both the Free Water and the hazy fuel layers just below the good fuel. While the fuel should be “Clear & Bright” unfortunately “Clear & Bright” fuel can sit on top of contaminated fuel – therefore, these lower layers should be regularly removed. Sadly, there is no single ‘quick fix’ option.