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Singapore Fuel Maintenance

Fuel Polishing Singapore

Diesel tank cleaning, fuel filtration, water removal, and microbial treatment for generator tanks, day tanks, and bulk fuel storage. Interion restores off-spec fuel and prevents the contamination that causes engine failures.

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Pre-Test & Post-Test Fuel Samples Generators Stay Online Singapore-Wide Coverage Emergency Response Available
Warning Signs

When Does Your Diesel Need Polishing?

Diesel degrades in storage. Singapore’s heat and humidity accelerate microbial growth, water ingress, and oxidation. These are the warning signs that your stored fuel needs attention.

Dark or discoloured fuel

ULSD should be clear to pale yellow. Brown or black colouration indicates oxidation, microbial growth, or sediment contamination

Visible water in tank sump

Water at the bottom of the tank creates a bacterial breeding ground. Even 0.1% water content causes microbial diesel bug growth

Slimy or stringy deposits

Black or brown biofilm on tank walls and filter elements is diesel bug (Pseudomonas, Hormoconis resinae). Requires immediate treatment

Blocked fuel filters

Frequent filter changes on a generator or vehicle indicate sediment or biological contamination in the tank, not just the fuel line

Generator fails load bank test

A generator that runs at no-load but fails under full load often has contaminated fuel causing injector fouling or filter restriction

Fuel older than 12 months

ULSD stored over 12 months in warm conditions degrades measurably — even without visible contamination, oxidation products affect combustion quality

Our Process

How Fuel Polishing Works

01

Initial Sample

Fuel sample taken from tank sump and midpoint. Tested for water, sediment, microbial activity, and visual clarity

02

Tank Sump Drain

Free water and settled sediment drained from tank sump. Disposed of as contaminated waste per NEA regulations

03

Polishing Circuit

Fuel recirculated through multi-stage filtration: coalescer for water removal, then 1–10 micron particulate filter

04

Biocide Treatment

If microbial contamination confirmed, biocide added at treatment dose. Fuel circulated to ensure full tank contact

05

Post-Treatment Sample

Final fuel sample taken and compared to pre-treatment. Results documented in service report

06

Service Report

Written report with pre/post sample results, volume treated, treatments applied, and maintenance recommendations

Who Needs This

Facilities That Can’t Afford Fuel Failure

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Hospitals & Healthcare

Generator failure during a power outage is a life-safety event. Annual fuel polishing is mandatory before commissioning tests

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Data Centres

Tier III/IV standards require clean, ready fuel. Contaminated fuel that starts a generator but causes injector failure under load is a hidden risk

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Construction Sites

Day tanks refilled infrequently from bulk storage can accumulate water and biological contamination, causing plant downtime

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Marine & Offshore

Day tanks on vessels storing marine diesel oil (MDO) in warm engine rooms are particularly susceptible to microbial growth

Related Reading

Book a Fuel Polishing Service in Singapore

Tell us your site address, tank capacity, and last service date. We’ll assess whether polishing or replacement is the right call and confirm scheduling within 24 hours.

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FAQ

Fuel Polishing: Common Questions

Fuel polishing is a process of recirculating stored diesel through a multi-stage filtration and water separation system to remove water, sediment, microbial contamination, and oxidation products. Unlike draining and replacing fuel, polishing restores degraded fuel to a usable standard while keeping the tank in service. It is typically performed on generator day tanks, bulk storage tanks, and marine day tanks.
For standby generator tanks that are not regularly turned over (consumed and replenished), annual fuel polishing is recommended. Critical facilities (hospitals, data centres) often polish every 6 months. Tanks in high-humidity environments or with a history of water ingress may need more frequent attention. The best practice is to take a fuel sample annually and test for water, sediment, and microbial activity — polish based on test results rather than a fixed schedule.
Fuel polishing removes physical contamination (water, sediment, biological material) and can significantly improve heavily contaminated fuel. However, if the base fuel has undergone severe oxidation (very dark colour, high acid number, significant gum formation), polishing may not restore it to BS EN 590 specification. In those cases, replacement may be more cost-effective. We take pre-treatment fuel samples and advise honestly on whether polishing is viable before starting work.
No — fuel polishing is performed with the fuel in the tank. The polishing unit connects to the tank’s existing fuel outlet and return connections (or temporary connections), circulates the fuel through the filtration system, and returns cleaned fuel to the tank. The generator or equipment can typically remain in standby mode throughout the process. Only the tank sump drain (removing settled water and sediment) requires a brief shutdown of the fill point.
Diesel bug is a collective term for microorganisms (bacteria and fungi, particularly Hormoconis resinae and Pseudomonas species) that grow at the water-diesel interface in storage tanks. Singapore’s warm, humid climate accelerates growth. Signs include black/brown slimy deposits, dark fuel, and frequent filter blockages. Fuel polishing removes biological material through fine filtration, and biocide treatment kills remaining organisms. Without water removal, diesel bug will regrow — so treating the root cause (water ingress) is essential alongside polishing.