Vectec - Total Fuel Management

Dirty Diesel - contaminated fuel


diesel sludge

Storage of fuel allows several elements to cause fuel contamination.

Dirty diesel is simply contaminated diesel fuel. 

Water - This easily enters the fuel tank via condensation, through vents and loose fittings. Even freshly refined fuel contains some water so no matter how well maintained a storage system is, a water bottom is invariably present. Diesel now contains 5% biofuel and this % is soon to increase. Biofuel increases the ability of normal diesel to absorb water.

Distillation Residues -There are refining standards that govern the quality of petroleum diesel but fuel is not always supplied direct to you from the refinery.

Inorganic Matter - e.g. rust and paint flakes, sand, dust or ethanol.

Organic Matter - i.e. microbes. Microbes live in water and feed on the fuel in fuel storage tanks. They multiply and form colonies on the fuel/water interface, i.e.where the water at the bottom of your tank meets the fuel above it. They produce highly corrosive organic acids,  slime and sludge.

Click here to find water and particle filters on pages 45-50 of the Fuel Equipment Catalogue.

Dirty diesel causes various problems

clogged filterdirty filter



• Corrosion of your fuel tank.
• Failure of fuel pumps.
• Clogging of filters.
• Sludge formation.
• Fuel additive degredation and loss of effect.
• Foul odour.


All in the above list are caused by microbes and their by-products

Microbes need only a drop of water to start a colony. It is the presence of water along with the darkness and warmth of a fuel tank that provides microbes with the conditions they need to live, grow and multiply. It is a myth that it is possible to remove microbes completely from fuel unless it is stored in a vacuum.

Click here to discover how Vectec can maintain and repair your fuel storage and dispensing equipment.

The effects of fuel contaminated by micro-organisms on Vehicle Performance

The effect of microbe contaminated fuel on fuel injection equipment is to impair performance and to increase wear and tear. It causes poor combustion and loss of engine power. It also blocks fuel filters, reduces the life of componants and increases servicing costs.


The higher water content of biodiesel immediately provides microbes with a very attractive environment. For biodiesel , the amount of exposure to condensation and water leaks, and the time in undisturbed storage before microbes grow and mutiply is much shorter than that of diesel. Biofuels deteriorate faster than conventional diesel and today's diesel fuel, as already stated, now contains biofuel.

Many modern engine running problems and fuel stock wastage is caused by microbial contamination brought about by the presence of water in biofuels.

Control of microbes in fuel

Step one - test your fuel and monitor contamination levels

Step two - Preventative maintenance - stop microbes colonising and stop them before they reach your fuel tank.

Biocides in fuel

Biocides are being increasingly used to manage microbial activity in fuel. They are highly toxic and they require special procedures and extreme care in handling. Biocides kill some bacteria but leave others to flourish. The effects and environmental damage of biocides passing via fuel through an engine and into the atmosphere are not at present known.


Purefuel Conditioner


Purefuel Conditioner is a eco friendly system developed by Purefuel Technologies that addresses microbiological growth in fuels.




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