down emergency standby power generators exactly when they were being counted on in the middle of a
disaster. And the number of hurricanes, wildfires, blackouts, floods, earthquakes and the like in recent years
has added significantly to the lore, though most are closely guarded stories and a PR person’s nightmare.
The frightful truth is that many emergency generators—an organization’s last line of defense in a catastrophe—
will not perform as expected if and when that time comes. This article will share some insights into the issue to
hopefully raise the percentage of emergency backup power systems that will operate as planned when
At its essence, poor fuel quality is about what ends up in fuel that doesn’t burn well, and the complete story will
surprise even veteran operations managers. Diesel fuel contaminants should be grouped into the following
categories: Water; Microbial Growths; Inorganic Particulate Matter; and naturally forming Fuel Breakdown By-
Products. The origins of them all can be traced to either a site-specific problem or in a fuel delivery from
upstream in the supply chain.
Water is a widely acknowledged concern, but it need not be a problem as long as some manner of routine fuel
maintenance is performed. If a tank is well-designed and is in good condition, with no means of water leaking
in at the site, then only small amounts of water should be present. Water appears quite normally in most tanks
This water can be removed easily through the use of a wide range of solutions that include absorptive
eliminators and filters, coalescers, centrifuges and the like. All mobile tank cleaning systems used by tank
cleaning services and permanently installed conditioning and filtration systems utilize one or more of these
approaches and are effective at removal of normal levels of water content. A quality multi-spectrum additive
often includes an emulsifier which can also pass small quantities through the system.
Microbial contamination (bacterial and fungal growth) is the most frequently mistaken problem. It only exists
where there is water for it to grow in, so if you are diligent in carrying out a fuel maintenance program, you
should never see the problem. Where it does exist in a long-ignored tank, microbes feed on the fuel, multiply
and excrete waste products, all of which will end up clotting in your filters. These by-products are highly
corrosive and pose a threat to many tanks.
The problem is that clogged filters are widely misinterpreted as containing microbial products, when they
actually most often are deteriorated fuel by-products (sludge). This leads to endless streams of toxic biocides
being needlessly dumped into tanks, which, when mistakenly used, make the problem worse. Often the result
is diesel fuel now so spoiled that it needs to be disposed of and replaced, a costly and unnecessary
consequence with serious environmental impacts. Not to mention that it may have sidelined the generator for
several days. Again, take care of the water, and you’ll never need a biocide.
Inorganic Particulate Matter
Other particulate pollutants in diesel fuel are mostly dirt, rust and other metallic particles that find their way into
the fuel either during the many tank transfers that occur in the supply chain or from a corroding tank
somewhere along the line. It is infrequent that the level of particulate matter is very high and is generally welltreated through conventional filtration that accompanies a standard tank cleaning system or onboard
permanent tank-side solutions.