The Fatberg Problem: Grease Traps May Do More Harm Than Good

Wastewater grease traps, normally seen as sewer system protection, may actually cause more harm than good.

A research team from the University of Hawaii recently found that microorganisms in wastewater grease traps may negatively affect deposits of fat, oil, and grease (FOG) in sewers. They recently published their findings in Environmental Science: Water Research & Technology.

“Together, our data indicate that microbial activities in grease interceptors can significantly impact the quantity and profile of long chain fatty acids, which should be taken into consideration in the design and operation in order to reduce the formation of fat, oil, and grease deposits in sewer systems,” the study said.

The problem is a little something called “fatbergs.”

“Often known as fatbergs, the hardened FOG deposits are made up mostly by calcium salts of long chain fatty acids, rather than simply fats and cooking oils entering wastewater pipelines. They cause severe problems for those maintaining the sewers and, in worst-case scenarios, can lead to sewer overflows and sewer system degradation,” according to a release from the University of Hawaii.

Tao Yan, one of the researchers, weighed in on the study.

"We are interested in the biological processes that contribute to sewer systems deteriorating and in developing engineering solutions that can improve the sustainability of sewer infrastructure and help protect public health and the environment," he said.

“[The researchers] replicated the conditions within grease interceptors — where microorganisms from food waste can thrive — in their laboratory. It was found that the process increased the concentration of fatty acids within the traps and in the water that would flow into a sewer pipeline,” the statement said.

Does that mean grease interceptors should be thrown out altogether? Maybe not.

“In light of these findings, Dr. Yan advises grease interceptor designers to consider microbial activities to maximize their effectiveness,” the statement said.

To read more about FOG visit Water Online’s Sewer And Sewer Line Maintenance Solutions Center.