Der vorliegende Forschungsbericht befasst sich mit den derzeitigen Unsicherheiten bezüglich der technischen Nutzungsdauer und des Alterungsverhaltens der gängigsten Renovierungsmethode in Kanalnetzen, dem Cured in Place Pipe (CIPP) Schlauchlining. Ziel dieser Arbeit ist die Entwicklung einer fundierten Datengrundlage für eine Schlauchliner-Überlebenskurve für die Anwendung in Alterungsmodellen. Das methodische Vorgehen umfasst (i) eine Literaturrecherche, (ii) Interviews mit Kanalsanierungs-Expert:innen sowie (iii) eine Auswertung von Daten der Berliner Wasserbetriebe zur Erstellung einer aktualisierten und geeigneten Datengrundlage für die Überlebenskurven. Dabei zeigen sich in der Auswertung der Literatur und den Interviews mehrheitliche Schätzungen der Nutzungsdauer von Schlauchlinern von über 50 Jahren. Die Untersuchung zeigt jedoch auch, dass diese von vielen Faktoren beeinflusst ist und ein Mangel an belastbaren Daten besteht. Weitere Untersuchungen an langjährig betrieben Schlauchlinern sind daher zwingend notwendig. Der Einbau, insbesondere der Aushärtungsprozess hat sich als Haupteinfluss für Defekte und Mängel an Schlauchlinern gezeigt. Eine Standardisierung der Schadenserfassung und Zustandsbeurteilung von schlauchlinerspezifischen Schäden sowie die Etablierung zerstörungsfreier Inspektionsmethoden sind erforderlich, um das Alterungsverhalten zukünftig besser zu verstehen. Empfehlungen umfassen die Verbesserung der Datenerhebung während des Betriebs, Ein- und Ausbaus von Schlauchlinern, die Erweiterung der Qualitätssicherung beim Einbau, sowie die Untersuchung von Schadenseinflüssen auf die Nutzungsdauer und den Erfahrungsaustausch zwischen Betreibern.

This bachelor thesis examines the influence of precipitation events and urban stormwater runoff on the concentrations of persistent and mobile substances (PM) in Berlin's surface waters. The analysis includes concentrations of 69 substances from four substance groups (VOCs, PAHs, PFAS, pesticides) that were recorded at 24 surface water sampling sites. Using precipitation data from 32 locations in Berlin, the concentrations were categorized according to dry weather, rain, and heavy rain influence. Statistical analyses for comparing these categories were performed using the Kruskal-Wallis and Dunn tests. Additionally, the concentrations in the surface waters were compared to those in Berlin's stormwater runoff using box-whisker plots.

13 of the investigated substances show significantly higher concentrations during rainfall or heavy rain events. This can be attributed to the input of these substances into surface waters through rainwater runoff. Particularly PAHs show notable concentration increases in Berlin's surface waters during precipitation events. PFOA and PFOS, two representatives of the PFAS group, exhibit a more complex behavior pattern depending on precipitation events. During light rainfall, their concentrations in surface waters decrease, while heavy rain events lead to increased concentrations. For pesticides and VOCs, the results are less conclusive, partly due to limited data availability.

This analysis provides valuable insights into the transport of various substance groups within the urban water cycle. The findings expand the scientific basis for developing targeted protection measures for urban waters.

An innovative circular economy (CE) system was implemented at the wastewater treatment plant (WWTP) in Brunswick. The performance of the CE system was evaluated for 4 years: the thermal pressure hydrolysis enhanced the methane production by 18% and increased the digestate dewaterability by 14%. Refractory COD formed in thermal hydrolysis and increased the COD concentration in the WWTP effluent by 4 mg L−1 while still complying with the legal threshold. Struvite production reached high phosphorus recovery rates of >80% with a Mg:P molar ratio ≥0.8. Nitrogen was successfully recovered as ammonium sulfate with high recovery rates of 85–97%. The chemical analyses of secondary fertilizers showed a low pollutant content, posing low risks to soil and groundwater ecosystems. The total carbon footprint of the WWTP decreased due to enhanced biogas production, the recovery of renewable fertilizers and a further reduction of nitrous oxide emissions. Using green energy will be crucial to reach carbon neutrality for the entire WWTP.

Highlights

• PFAS and other persistent substances found in industrial urban stormwater runoff

• PFOA-equivalent concentrations for PFAS-24 exceeded EU proposal for surface- and groundwater

• Urban stormwater runoff from industrial sites is one source of PFAS in surface waters

Currently, there is uncertainty about emissions of pharmaceuticals into larger closed ecosystems that are at risk such as the Baltic Sea. There is an increasing need for selecting the right strategies on advanced wastewater treatment. This study analysed 35 pharmaceuticals and iodinated X-ray contrast media in effluents from 82 Wastewater Treatment Plants (WWTPs) across Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland and Sweden. Measured concentrations from Finland and Denmark were compared to predicted effluent concentrations using different levels of refinement. The concentrations predicted by the Total Residue Approach, as proposed by the European Medicines Agency, correlated with R(2) of 0.18 and 0.031 to measured ones for Denmark and Finland, respectively and the predicted data were significantly higher than the measured ones. These correlations improved substantially to R(2) of 0.72 and 0.74 after adjusting for estimated human excretion rates and further to R(2) = 0.91 and 0.78 with the inclusion of removal rates in WWTPs. Temporal analysis of compound variations in a closely monitored WWTP showed minimal fluctuation over days and weeks for most compounds but revealed weekly shifts in iodinated X-ray contrast media due to emergency-only operations at X-ray clinics during weekends and an abrupt seasonal change for gabapentin. The findings underscore the limitations of current predictive models and findings (...) demonstrate how these methodologies can be refined by incorporating human pharmaceutical excretion/metabolization as well as removal in wastewater treatment plants to more accurately forecast pharmaceutical levels in aquatic environments.