Assessing the Efficiency of Different Net Mesh Size for Microplastic Retrieval of Marine Debris in the Chesapeake Bay

Pollution by microplastics is an ecological threat and their removal poses large engineering challenges because of their size and distribution in the environment. One solution has been to use netting attached to boats to capture and remove microplastics and other marine debris. This thesis evaluates the effectiveness of different net mesh sizes in removing microplastic surrogates from watersheds, with a focus on the Chesapeake Bay. Two core research questions guide this study: 1) How long does it take for various mesh sizes to clog when filtering microplastic surrogates? and 2) How can turbidity be used as an efficient indicator of microplastic concentration when removing marine debris? Given the ecological and economic importance of the Chesapeake Bay, understanding and mitigating microplastic pollution is critical. This research explores how mesh size influences filtration efficiency and clogging time, as well as how turbidity readings correlate with microplastic removal. Conducted through Penn State Harrisburg and Multi-Campus Research Experience for Undergraduates (MC REU), the study found that finer mesh yields cleaner water but slows flow rate—a trade-off that can be optimized. Notably, 200 µm polyester mesh matched the turbidity reduction of 105 µm mesh after 30 minutes, highlighting that slightly larger meshes may offer similar results with less clogging. These findings contribute to improved microplastic removal strategies while considering both filtration performance and hydrodynamic constraints in varying aquatic conditions. One question that the literature raised was how surface charge and ionic interactions influence microplastic behavior in freshwater versus saltwater environments. This was not investigated but should be considered in future research.