Diesel-powered systems today face a silent but aggressive threat: water, microbial sludge, and acidic contamination inside the fuel tank. Even with quality diesel at the pump, tanks and engines are being compromised by microbial growth, biofuel instability, and inadequate filtration.

At Lancing Marine, we’ve stopped relying on filters alone. We've adopted a better approach—a permanent, physical separator that removes the problem before it reaches your injectors. This blog explains how the Micro-Separator® solves water and sludge contamination and secures uptime for marine and industrial diesel systems.

We fitted the Micro-Separator® to our own test boat after fighting blocked filters on a common-rail diesel. We tried double filters, water separators, and coarse strainers—but in rough weather, contamination always found its way through. Since installing the unit, downtime has dropped and filter elements stay clean.

Micro-Separator Range

Micro-Seperator Models: MFC-60, MFC-110, and MFC-750

Model	Max Flow Rate	BSP Connection	Weight
MFC-60	100 L/hr	⅜” BSP	1.9 kg
MFC-110	750 L/hr	½” BSP	2.1 kg
MFC-750	1900 L/hr	¾” BSP	7.0 kg
MFC-5600	5600 L/hr	1½” BSP	27.25 kg
MFC-9000	9000 L/hr	2” BSP	35.0 kg

Models up to 17,500 L/hr available. Ask us to help size your system.

View Pricing – Page 94

The Problem: Water & Sludge in Your Diesel

Water enters your diesel through condensation, poor storage, or handling. Today’s low-sulphur and biofuel diesel blends are prone to microbial growth, which produces sludge, acid, and sticky by-products.

Common rail systems make things worse by returning up to 90% of heated fuel (up to 60°C) back to the tank—rich in oxygen and ideal for microbial growth. With over 150 bacteria types able to feed on diesel, tanks become biological reactors unless managed correctly.

1. Blocked filters that stop fuel flow and shut engines down.
2. Worn or failed injectors—especially on common rail systems.
3. Damaged high-pressure pumps due to sludge and acid.
4. Overheating due to lack of fuel flow and injector cooling.

Traditional filters clog fast and don’t address the tank itself. They trap the problem rather than solve it, and often fail when contamination is stirred up by sea motion or return fuel flow.

Modern diesel engines—especially common rail types—are extremely sensitive to contaminated fuel. The combination of biofuel blends, warm return flow, and moist environments makes marine tanks a breeding ground for microbial growth.

Bacterial growth occurs at the interface between fuel and water — this is the unseen danger within marine fuel tanks.

Water finds its way into tanks via condensation, tank venting, poorly sealed caps, or contaminated deliveries. It settles beneath the diesel layer, creating a **fuel–water boundary**. This layer is where microbial contamination takes hold.

Over 150 species of bacteria, fungi, and yeasts feed on diesel. They multiply rapidly at the boundary layer, forming corrosive sludge and acids. The result: blocked filters, damaged injectors, and failing high-pressure pumps.

In common rail engines, up to 90% of heated return fuel (often >60°C) is cycled back into the tank, rich in oxygen—perfect conditions for microbes to thrive. Standard filters merely trap the debris but do not solve the tank-side contamination.

Once stirred up—by vessel motion or refuelling—sludge overwhelms filters and risks a full engine shutdown. Preventing this requires not just filtering the fuel, but addressing the root cause: water and microbes in the tank itself.

Visible sludge in a sample jar from a vessel fuel tank

The Solution: Micro-Separator® Fuel Water Separator

The Micro-Separator® is not a filter in the conventional sense. It’s a compact, inline mechanical purifier designed to remove the root causes of diesel system failure—without clogging, and without the need for replacement elements or regular servicing. By applying principles of centrifugal separation, coalescence, and gravity, it continuously purifies diesel fuel as it flows.

1. Removes up to 99.5% of water: Even tiny droplets are separated out and collected before they can cause damage.
2. Captures sludge, rust, and sand: Effectively ejects solid particles and microbial waste that paper filters struggle to hold.
3. No filter elements to replace: The unit contains no cartridges, screens, or media—meaning lower cost of ownership and no maintenance interruptions.
4. Long-life construction: Engineered from corrosion-resistant alloys and ceramics, the Micro-Separator® is rated for the life of the engine it's fitted to.

Because it operates inline, the Micro-Separator® can be installed directly before your lift pump or secondary filters. It can also be fitted into return loops for ongoing tank conditioning. It performs especially well in systems where fuel recirculates—such as common-rail diesels or generator standby tanks—gradually replacing contaminated fuel in the tank with clean, polished diesel.

How It Works: Physics, Not Filters

The Micro-Separator® uses natural forces—no electronics or chemicals:

1. Centrifugal force: ejects heavy solids and water outward.
2. Surface tension & coalescence: binds micro-droplets for removal.
3. Gravity: drops contaminants into a drainable sump.

Fuel flows in a spiral motion through the unit, where solids and water are separated out and clean diesel continues to the engine. Over time, even contaminated tanks improve, as common-rail systems return large volumes of polished fuel back to the tank.

Water Drain Alarm for Fuel Micro-Separator