It has now been over a decade since the issue of organic micropollutants at Swedish wastewater treatment plants first gained attention. Since then, several municipalities, wastewater treatment plants and water utilities across Sweden have worked intensively on this issue. With support from the Swedish Environmental Protection Agency (Naturvårdsverket), numerous feasibility studies and pilot projects have been conducted to explore specific treatment options at different wastewater treatment plants.
Naturvårdsverket’s initiative was conducted between 2018 and 2023 and resulted in around 70 reports, which collectively contain a vast amount of chemical analysis data on organic micropollutants, including pharmaceuticals, antibiotics, and hormones.This report summarizes and further develops the results from a selection of the studies mentioned above. The report investigates the occurrence, distribution, and treatment of pharmaceuticals and other micropollutants in Swedish wastewater treatment plants. The aim is to improve the understanding of their environmental impact, analyze methods for predicting wastewater concentrations, and evaluate the effectiveness of advanced treatment technologies.
Chapter 1 provides background information on the sources, distribution, and environmental effects of micropollutants, with a focus on pharmaceuticals. Current and upcoming regulations are discussed, including the EU Urban Wastewater Treatment Directive and the Priority Substances Directive, which impose stricter treatment requirements.
Chapter 2 describes the compiled dataset used in the study, covering data from Swedish wastewater treatment plants between 2018 and 2024. The dataset includes information on pharmaceutical concentrations, wastewater flows, and conditions of the receiving water, as well as metadata on treatment plant capacity and technologies.
Chapter 3 analyzes how micropollutants are transported and diluted in receiving water bodies. The variation in dilution between different water bodies and seasons is a key factor influencing environmental concentrations. Findings from previous studies and national monitoring programs are referenced.
Chapter 4 presents different methods for analyzing and predicting pharmaceutical concentrations in wastewater. Factor analysis and multivariate analysis are used to explore correlations between parameters such as nitrogen removal, population size, and incoming concentrations. A sales-based model is evaluated for predicting pharmaceutical concentrations based on sales data, using diclofenac as an example. The results show that the model provides reasonable estimates but has uncertainties, particularly regarding excretion factors and local sales data.
Chapter 5 discusses quaternary treatment, including ozonation and activated carbon, as techniques to reduce micropollutant emissions. Efficiency varies between substances, and the choice of indicator substances is crucial for accurately reporting treatment performance.
Chapter 6 presents conclusions and recommendations. The report highlights that a combination of chemical analysis, predictive models, and advanced treatment technologies is necessary to effectively manage micropollutants in wastewater. To improve predictions, more detailed data on pharmaceutical sales, consumption, and recipient conditions are required. A key future challenge is integrating the dilution factor into analyses to better estimate final concentrations in the receiving water.