Analysis of the microplastic load reduction by the Ithaca Area Wastewater Treatment Facility

In recent years, various studies have focused on wastewater treatment plants, identified as a potential source of microplastics in aquatic environments. Indeed, microplastics have been found in various amounts in wastewater effluent worldwide. Due to the environmental and health danger posed by these plastic particles, it is imperative to have a good idea of the actual quantity and types of microplastics entering the environment. The goal of this study was to analyze the microplastic concentration in both influent and effluent wastewater of the Ithaca Area Wastewater Treatment Facility (IAWWTF) in Ithaca, NY, USA. Samples were processed following the NOAA wet peroxide oxidation and density separation method and were then identified by visual identification, using a digital microscope system at a 50x magnification. It was found that the microplastic concentration in influent wastewater was significantly higher than that in effluent wastewater and that the IAWWTF had an overall microplastic removal efficiency of 94.2%. However, given the large volumes of wastewater flowing through the WWTP, it was calculated that around 500 million microplastic particles entered the lake downstream (Cayuga Lake) daily. Plastic fragments and fibers were dominant in both influent and effluent samples. This study, therefore, shows that even if the removal efficiency of the IAWWTF is high, the treatment plant can still be seen as a source of microplastics in the aquatic environment downstream.