Bacterial infection/ bacteria

See microbial growth


Chemical treatment for bacterial infections in fuel.


a fuel derived immediately from living matter.


Biomass is organic matter derived from living, or recently living organisms.


An organic matter by product. In fuel where a bacterial infection has been present, it often appears as a film or hard matter lining a tank’s inner surfaces or choking the diameter of pipe work.


(standing for building management system) is a remote control and monitoring solution, designed to allow pieces of equipment to communicate with each other.


A key feature of the W-PFS range which separates emulsified water and particulate to 2 micron.

Contamination / contaminates

This is anything that is in the fuel which should not be there. This can include dirt (see particulates) bacteria (see microbial infection) and water (see free water and emulsified water). Find out more about contamination.

Diesel Bug

See fuel bug.

Diesel Cleaning

Fuel Polishing or cleaning system ie WB Range or W-PFS Range.

Diesel Polisher

Fuel Polishing or cleaning system ie WB Range or W-PFS Range.

Direct inject engine

This are the modern form of engines. These work at much higher pressures than normal engines.


A world-wide collection of businesses who distribute our products to companies locally to them. Find out more about our World-wide Distributor Network.


Sometimes referred to as a filter. It is the piece of a fuel cleaner which collects contaminates.


The higher the emissions, the more it will cost the company. Contaminated fuel causes higher emissions, whereas filtered fuel significantly reduces emissions.

Emulsified water

Emulsified water is the water which is not separated. It is mixed in with the fuel and sludge (see sludge)


Frequently asked questions about fuel, WASP PFS Ltd and Fuel Polishing.

Filter / Filtering

A porous device for removing impurities or solid particles from a liquid or gas passed through it. Straining.

Fuel Bug

A common bacterial infection in diesel fuel.

Fuel Testing

Test to check fuel for water, contamination and bacterial content.

Free water

Free water is the water that has been separated from the diesel before the fuel polishing process has begun. Find out more about contamination.

Fuel additive

Fuel additives are substances or products that are added to fuel to improve its quality, or to prevent something like bacterial or fungal infection from happening. As an example, our WASP Biokem SP15 is excellent at killing bacteria and fungi in fuel, which can lead to clogged filters.

Fuel filters

Fuel filters are products that are added to a fuel system in an attempt to filter out contaminants such as water and dirt so as to ensure proper functioning. Our industry leading fuel filters provide great protection for virtually any type of fuel system. Alt: Brandstoffilter (Dutch)

Fuel polishing

Fuel polishing is an industry buzz word that simply means fuel cleaning. It really is as simple as that with no 'magical' element to it. You may also hear it described less so as fuel conditioning, but regardless of how its described, the service is the same. Fuel that is cleaned with one of our fuel cleaning systems will ultimately last longer, meaning less waste and will hopefully keep your equipment free of damage that is normally attributed to dirty fuel. ALT: Kraftstoff Polieren (German), yakıt parlatma (Turkish), پرداخت سوخت (Persian), تلميع الوقود (Arabic), polering brændstof (Danish), brandstof polijsten (Dutch), polissage de carburant (French), polerowanie paliwa (Polish), el pulido de combustible (Spanish).

Fuel related breakdowns

Fuel related breakdowns happen when the fuel in a back-up generator has not been cleaned. The unclean/contaminated fuel causes higher emissions and breakdowns’, which reduces the back-up generator’s ability to work efficiently or at all.

Filter System

Alt: filtratie system (Dutch)


These turn liquid diesel into spray, which increases the surface area so that it can be burnt, and thus removed.

Heating oil

Fuel stored in a tank for use for heating purposes in properties not on the national grid.


We have been in the industry for more than 25 years. Read more.


Markets such as Data centres, Construction, Marine, Finance, Stocks and Shares, Healthcare etc.


A contamination in fuel which effects quality and renders fuel out of spec.

ISO standards

ISO International Standards ensure that products and services are safe, reliable and of good quality. For business, they are strategic tools that reduce costs by minimizing waste and errors, and increasing productivity.


Lit/min stands for the flow rate, which is the number of liters per minute that a system can clean.


Alternative expression for WASP Fuel Polishing Unit.

Microbial growth

Bacteria that grows in the diesel, particularly when there is water. Find out more about contamination.


Microns are the ratings which denote what particles are filtered through the systems. For example, 30 microns will not allow anything that is 30 microns or bigger through the filter. Conversely, 2 microns will not allow anything bigger than 2 microns through the filter. This is why we are always innovating to reduce the microns down to 1 and 0.5 microns.

Particles / particulates

Solid matter that should not be in the fuel. For example, dust, rust or sand. Find out more about contamination.


a viscous liquid derived from petroleum, especially for use as a fuel or lubricant.

PLC control

Programmable logic controller

Polish / polishing / fuel polishing

Term created by WASP PFS Ltd to explain cleaning fuel to a low mircon level, removing water, contaminations and sediment.

Quality Fuel

Fuel is typically measured by ISO specifications. If the fuel quality meets or exceeds the ISO standards, then this is classed as good quality fuel.


This is dirt/particles in the diesel which have a heavier gravity than the diesel. Find out more about contamination


Separ are the largest fuel polishing and fuel filtration supplier in Europe, supplying fuel filtration and preservation equipment to the generator, marine, building services, truck, bus and heavy equipment markets since 1980’s.


The result of contaminated fuel (see contamination) and microbial growth


Replacement parts for our units which include elements (filters) and gaskets.

Specification (fuel)

The specification that all gas oils/ fuels must meet.

Standby / back-up generator

A generator that is used for emergencies when there is a shortage of power or a power failure (see fuel related breakdowns)


a porous device for removing impurities or solid particles from a liquid or gas passed through it.


Alternative term for our fuel polishing units.


Stands for WASP Pure Fuel Systems.

Water Separator

Filter to remove water in fuel. ALT: Wasserabscheider


WB is our classic range of fuel cleaning units.


W-PFS is our premium range of fuel cleaning units.

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