Microplastic Types in the Wastewater System—A Comparison of Material Flow-Based Source Estimates and the Measurement-Based Load to a Wastewater Treatment Plant

Abstract

Microplastics are omnipresent in the environment, and wastewater treatment plants (WWTPs) have been highlighted as a transport pathway. The aim of this study is to contribute to increased understanding of microplastic sources in wastewater and test the possibilities of source tracking. Previous research has focused either on estimating microplastic contribution from various sources or on quantifying occurrence based on measurements. In this paper, these two approaches are compared. Microplastic types detected in the influent to a WWTP in Sweden are compared with estimations of sources in the WWTP catchment area. The total load from the identified sources was estimated to 1.9–14 tonnes/year, and the measurement-based load was 4.2 tonnes/year. In general, there was a good agreement between the two approaches; microplastic types with large shares at the inlet also had large contributions in the source estimates. An exception was cellulose acetate, which was not found at the inlet despite a large theoretical contribution. Many uncertainties remain, which lead to large intervals for the source estimates. The comparison can give an indication into which part of the intervals is most likely. Investigating more WWTPs with different characteristics and including particle morphology will further increase the understanding of sources that contribute to the presence of microplastics in wastewater.

Using information flow analysis to establish key data gaps in the assessment of marine microplastic pollution

“…The challenges of defining the sources, pathways, and fate of MP pollution in MP research (Fältström et al., 2021; Woods et al., 2021) could be due to the complexity of MPs in terms of their characteristics. For example, complexity related to the diverse sizes, morphologies, chemical compositions, associated additives and stabilizers, and colors of MPs (Rochman et al., 2019).…”

“…For example, complexity related to the diverse sizes, morphologies, chemical compositions, associated additives and stabilizers, and colors of MPs (Rochman et al., 2019). In addition to the inherent complexity of MPs as contaminants, the types of environments where they originate, pass through, and are deposited are also complex (Fältström et al., 2021).…”

“…Given that the bibliometric analysis resulted in a weak link strength between MFA and LCA as well as between ecotoxicology and LCA, these areas of study were color coded in the least prevalent category (red) in the IFA. MFA can provide information that connects the quantity of MPs present in the environment and the quantity of MPs present in a system (i.e., their assumed pathways from the anthropogenic activities to nature) because the method considers the flows, stocks, inputs, and outputs of a substance (Fältström et al, 2021). MFA can also be a useful tool for populating LCI, a crucial step in LCA and required for LCIA (Wang et al, 2022).…”

Notes on Common Misconceptions in Microplastics Removal from Water

“…In recent years, microplastics occurrence in water and their removal has come to the forefront of research interest [17][18][19][20][21][22][23][24][25]. To give an example, three local drinking water treatment plants were tested for the presence of microplastic particles in water before and after treatment, with no special technologies for microplastics removal [26,27].…”