Fatberg. Credit: Seeing Sanitation (CC BY 2.0, https://creativecommons.org/licenses/by/2.0/deed.en)
Australian researchers have designed a way to prevent up to 98% of fats, oil and grease (FOG) from being flushed down the drains of commercial kitchens, improving protection of sewer infrastructure and reducing the costs of maintenance.
FOG combine with non-biodegradable wipes, rags, tissues and sanitary products which people flush down the toilet to form rock like masses called ‘fatbergs’ which clog sewers worldwide.
“While traditional interceptors only remove around 40% of fats, our system achieved up to 98% – even when tested with actual kitchen wastewater,” says Dr Nilufa Sultana from the Effective Technologies and Tools (WETT) Research Centre at RMIT University.
Sultana and collaborators have shown their improved grease interceptor works effectively on real-world dishwasher and sink wastewater in a new study in the journal of the American Chemical Society (ACS) ES&T Water.
Dr Nilufa Sultana and Dr Biplob Pramanik next to their anti-fatberg innovation in their lab at RMIT University. Credit: Will Wright, RMIT University
The system introduces a series of 4 ‘baffles’ into a conventional double-chambered grease interceptor – 3 in the 1st chamber and 1 in the 2nd.
The baffles act as physical barriers to slow down the flow of wastewater to better separate out larger fat particles. Alum, a chemical commonly used in water treatment, is also added to clump the smaller, suspended fats (less than 150 micrometres) for removal.
WETT Director Dr Biplob Pramanik says, “Traditional grease traps aren’t designed to catch the finer particles and emulsified fats in modern kitchen wastewater. Our system targets all fat types, even hard-to-remove emulsified fats that slip through conventional traps.”
The system works well alongside high temperature water and detergent use, which promotes the formation of smaller particles and emulsified fats.
Dr Biplob Pramanik and Dr Nilufa Sultana examine treated kitchen wastewater. Credit: Will Wright, RMIT University
“This is a major step forward in preventing FOG from entering our sewers from the biggest contributors: commercial food establishments,” Pramanik says.
“Fat, oil and grease blockages can lead to sewage spills in our streets and waterways,” adds co-author and RMIT Emeritus Professor Felicity Roddick.
“This research shows we can stop the problem at its source, with a simple upgrade to the systems food businesses already use.”