Fatbergs are massive, concrete-like clumps of cooking oil, grease, nappies, wet wipes, and other debris that accumulate in sewers, blocking the network. They’re notoriously difficult to break apart and can grow to staggering sizes. In 2017, London recorded a fatberg measuring 820 ft (250 m) long and weighing 130 tons (118 tonnes)—roughly equivalent to the weight of two Airbus A318 planes.

Figure 1. Fatberg-Fighting Tech Could Slash City Sewer Costs.

Clearing fatbergs before they cause sewage backups requires constant monitoring and manpower. In the U.S., it’s estimated that breaking them up and repairing the resulting damage costs up to US$25 billion annually. Figure 1 shows Fatberg-Fighting Tech Could Slash City Sewer Costs.

Engineers at Australia’s RMIT University are developing two innovative methods to reduce these buildups—solutions that could save cities billions of dollars worldwide each year.

But how do fatbergs form in the first place? Fat, oil, and grease (collectively known as FOG) combine with sewer water and calcium leached from concrete pipes, gradually solidifying over time. Most FOG originates from domestic and commercial kitchen wastewater. While plumbing devices called grease traps capture a large portion of FOG before it enters sewer lines, some still slips through, contributing to these massive sewer blockages.

Clearing fatbergs before they cause sewage backups requires constant monitoring and manpower. In the U.S., it’s estimated that breaking them up and repairing the resulting damage costs up to US$25 billion annually.

But how do fatbergs form in the first place? Fat, oil, and grease (collectively known as FOG) combine with sewer water and calcium leached from concrete pipes, gradually solidifying over time. Most FOG originates from domestic and commercial kitchen wastewater. While plumbing devices called grease traps capture a large portion of FOG before it enters sewer lines, some still slips through, contributing to these massive sewer blockages.

Stopping Grease in Its Tracks

To tackle FOG at its source, the RMIT team has developed an improved grease trap that captures more than twice as much fat as conventional systems. While it looks like a standard grease trap from the outside, its interior features a series of physical baffles that slow wastewater flow and separate larger fat particles. Afterward, alum—a common water treatment chemical—is added to clump together smaller, suspended fats, making them easier to remove.

The system isn’t perfect yet—the researchers are working to apply fluid dynamics principles to improve FOG removal without relying on chemicals, paving the way for commercial use that meets public infrastructure standards.

Better Pipes = Fewer Fatbergs

For the second part of their approach, engineers at RMIT developed a new coating for the interior walls of sewer pipes.

They first recreated fatberg formation in a controlled setting using concrete blocks (similar to sewer pipes) and synthetic FOG water over 30 days. This allowed them to compare fatberg growth on regular concrete blocks versus blocks treated with their new zinc-enhanced polyurethane coating.

Source:NEW ATLAS

Cite this article:

Priyadharshini S (2025), Tech That Tackles Fatbergs Could Save Cities Billions in Sewer Maintenance, AnaTechMaz, pp. 271