Water Resources Research Act Program

Details for Project ID 2020NC171B

Understanding the FOG deposit adhesion mechanism on different sewer line surfaces

Institute: North Carolina
Year Established: 2020 Start Date: 2020-02-29 End Date: 2021-02-27
Total Federal Funds: $12,000 Total Non-Federal Funds: $71,520

Principal Investigators: Joel J. Ducoste

Abstract: According to the US Environmental Protection Agency (USEPA), around 25% of the 23,000 to 75,000 Sanitary Sewer Overflows (SSOs) are due to sewer line blockages related to fat, oil, and grease (FOG) deposits. Engineered solutions to protect the collection system from FOG deposits are scarce. One possible solution is to reduce the FOG deposit’s ability to adhere to sewer surfaces. A recent study has revealed a significant reduction in FOG deposit formation and adhesion on fly ash (FA) replaced concrete surfaces and no adhesion detected on concrete coarse aggregate (granite) surfaces. Yet, the mechanism for reduced FOG solid deposition on any surface utilized in the sewer collection system is unknown. Understanding this unique and previously unknown phenomenon on FA replaced concrete and granite aggregate surfaces could lead to new strategies on treating pipe surfaces against FOG deposit adhesion. The objective of this proposed research is to understand the FOG deposit adhesion mechanism on different sewer pipe surfaces. This project has four research tasks. In Task 1, concrete samples containing 0% and 50% FA will be prepared with granite and limestone as coarse aggregates. Task 1 will also involve ceramic materials to mimic pore size and porosity of concrete materials to understand their role in FOG deposit adhesion. Tasks 2-4 will involve preparing coupons of concrete and coarse aggregates, vitrified clay pipe, and PVC pipe with different surface roughness and measuring the amount of FOG solids deposition under different wastewater conditions. The results from these tasks will be used to develop a FOG deposit adhesion model that characterizes the adhesion mechanistic process. Data from this research will provide North Carolina wastewater utilities with strategies to develop new construction materials or design future coatings that can enhance existing alternative sewer line materials to reduce FOG deposit accumulation on sewer surfaces.