Diesel Bug is the microbial contamination of diesel by bacteria and fungi such as: amorphothecaceae, ascomycota, desulfovibrio, flavobacterium, pseudomonas, aspergillus, etc.  Diesel Bug was always more or less a problem for diesel fuels, however, since the introduction of Ultra Low Sulphur Diesel (ULSD) it has become more and more evident, as the presence of sulphur was able to inhibit microbial growth in diesel fuels. The problem gets worse when biodiesel is added to ULSD and according to Australian Standard of fuel quality it can be up to 5%. The reason is that, compared to regular diesel, biodiesel is much more hygroscopic (attracts water). Studies found that biodiesel can absorb up to 25 more water than diesel and as the temperature increases above 35°biodiesel has an increased rate of 22.2ppm/°C – 9 times more than regular diesel. That is the reason why tanks situated in the engine room or in higher temperature areas have worse microbial contamination (up to few centimetres thick on the bottom of the tank). When that happens the primary fuel filters become constantly clogged, the corrosion of the tank is accelerated at the same time with the degradation of the fuel below the specifications of AS 3570.

Fuel contamination

Diesel fuel is transported from the refinery to the storage depots by tanker trucks, ships or pipelines. From there it is loaded into another tanker truck and delivered to your site. Every time diesel is transferred from one tank to another, it not only transfers the fuel but also the contaminants present.

Many people assume they are buying quality fuel that meets the required specifications in terms of ISO 4406 and diesel fuel cleanliness is rarely questioned. However higher fuel systems operating pressures, lower system tolerances and tighter filtration have pushed fuel cleanliness into the maintenance spotlight.

Water gets into fuels and oils by adsorption, condensation and human negligence. Dirt and water act as catalysts for the breakdown of fuel via oxidation and by supporting bacterial growth – diesel bug. Although water in fuel is often hidden from the naked eye and its inert properties supposedly render it “harmless”, it can be extremely detrimental to most systems.


Type of contamination

There are many different types of contaminants that could adversely affect, damage or even destroy a fuel injection  system. Bacteria, fungus, water, suspended microscopic particles, additives, wax are some of the main contaminants.


Mission critical problems

All critical infrastructure operators who own or tenant buildings rely on emergency building power generators during power outages. These buildings must have power supplied continuously to maintain insurance policy requirements (i.e. fire detection, security).

– Most of these operators have emergency generator fuel to allow at least 24 hours of operation.

– These generators are fed by one, or in most cases, multiple tanks of stored diesel.

– The quality of the stored diesel is both integral and critical to the reliable function of these generators.

– Microbial growth in diesel has accelerated year on year due to the reduction to almost zero of sulphur in diesel.

– The sludge layer caused by microbial growth is potent enough to cause fuel blockage, injector blockage and subsequently full engine failure.

– Regular cleaning of fuel to remove microbial growth is currently restricted to onerous, environmentally unfriendly and hazardous methods involving trucks, disposal, toxic chemicals, large numbers of staff, wastage and high costs.

– The CDA iCleanED replaces all the aforementioned negative treatment methods at significantly less cost with initial payback achieved after year one, and year two and onwards savings of 30% to 50%.

– With the above-mentioned iCleanED in place, any facility with stored diesel would be guaranteed a continual supply of clean, microbe free, water free, chemical free and particulate free diesel.