PILOT SCOPE - Southeast Center for Agricultural Health and Injury Prevention - PILOT PROJECTS Distribution Mapping for Microplastics and Biological Contaminants in Wastewater Treatment Straight Pipes

Microplastics (MPs) are an increasingly recognized contaminant in engineered water systems such as wastewater treatment plants (WWTPs), yet their fate and transport, and impact on pathogenic communities within these networks remains poorly understood. This study intends to utilize a controlled, closed-loop PVC pipe system that simulates pulse-flow wastewater conditions indicative of those found in household septic or WWTP infrastructure to evaluate pathogen and microplastic fate and distribution under varying conditions. To determine MP distribution, MP particles marked with a nile-red dye tracer will be introduced to a simulated wastewater solution and subjected to various pulse-flow circulation and retention times. By analyzing the movement and spatial distribution of MPs throughout the PVC pipe, flow dynamics in PVC wastewater pipes will be characterized for patterns based on microplastic particle size, shape, location, etc. To test the feasability of this method, we have outlined two objectives: (1) Determine end-point concentrations of microplastics and pathogenic communities in closed-loop straight pipe wastewater treatment systems with varying pipe material (PVC, cast iron, HDPE) and diameters (2”, 3”, 4”) under varying initial microplastic concentrations and retention/recirculation times (1 min., 30 min., 1 hr., 4 hr., 12 hr., 24hr., 48hr), and (2) Utilize microplastic dye tracers to investigate the spatial distribution of persisting microplastics along a closed-loop straight pipe wastewater treatment system with varying pipe types (PVC, cast iron, HDPE) and diameters (2”, 3”, 4”). The findings will offer insight into the fate and transport of MPs in real-world infrastructure networks and may potentially be used to develop transport models for predicting microplastic creation and accumulation in these networks.