(180a) Quantitative and Qualitative Analysis of Microplastics in City Wastewater Treatment Plant

Microplastics (MPs) are a growing concern for both society and the scientific community due to their widespread presence in the environment and potential health impacts. Urban wastewater treatment plants (WWTPs) serve as critical points where waterborne MPs can accumulate at high concentrations, presenting an opportunity for their removal as part of ongoing efforts to mitigate environmental contamination. MPs have been detected in oceans, rivers, protected areas, food, drinking water, and virtually every environment imaginable.

City wastewater treatment plants generally handle various types of microplastic particles originating from commercial and household materials, including textiles, detergents, pharmaceuticals, cosmetics, packaging, and other sources. In this study, utilizing the Renaissance Foundry Model (herein the Foundry) as our research methodology (Arce et al., 2015), we collected, processed, and analyzed wastewater from three distinct locations within a typical city wastewater treatment plant.

The Foundry is an innovation-driven learning platform that was used as an effective strategy to guide the research undertaken in this project. The platform leverages six foundational elements within two paradigms, the Knowledge Acquisition Paradigm (KAP) and the Knowledge Transfer Paradigm (KTP). According to the Foundry, the process of innovation starts with the identification of a challenge (i.e., the understanding of presence of MPs in wastewater) that impacts society and then moves towards the development of the Prototype of Innovative Technology (PIT), (i.e. obtaining information about MP types and concentration in various process units of city WWTPs), that addresses such a challenge. The KAP is critically important in learning important details about the challenge via the Learning Cycles and Documentation Cycles to facilitate knowledge acquisition as related to the challenge and to determine a set of Organizational Tools that guide the facilitation of the PIT. Here is where the KTP provides a useful path via the application of the Linear Engineering Sequence (LES). The entire process is further enhanced by Resources (i.e. experts, supplies, literature, labs, etc.) that assist in the transformation of the Challenge into the PIT. As in many innovation-driven processes, the researcher iterates between the KAP and the KTP until a suitable PIT has been developed.

As noted, the strategy just described is applied in this research project to obtain information about the type and concentrations of MPs in the selected process units of the city WWTP, the primary challenge anchoring this research. In turn, the samples collected from the influent unit, aeration tanks (biological reactor), and the effluent unit are used to perform a quantitative and qualitative analysis of microplastics and predict the plant’s ability to eliminate them from the water influent. As part of the Organizational Tools of the Foundry, we use guidelines for particle filtration and digestion and then microscopic techniques are applied. Specifically, we processed the samples through two-phase filtration and digestion steps before analyzing them with an FTIR (Fourier Transform Infrared Spectroscopy) Microscope to obtain the necessary characterization and information about concentration. As part of the PIT, during the analysis, we observed fewer microplastics in the effluent compared to the influent point of the plant; furthermore, we observed a high concentration of MPs in the aeration tanks, suggesting the sludge-holding tanks capture most of them. This information is important because the sludge, processed and used as fertilizer, still may introduce significant amounts of microplastics into the environment despite fewer being released into the local creek via the water effluent. This study will be useful to guide future research on microplastic degradation, aiming to find ways to break them down before they reach the sludge and are released back into the environment.