Maria Thiel

Zusammenfassung

Micropollutants (MPs) in wastewater pose a growing concern for their potential adverse effects on the receiving aquatic environment, and some countries have started requiring that wastewater treatment plants remove them to a certain extent. Broad spectrum advanced treatment processes, such as ozonation, activated carbon or their combination, are expected to yield a significant reduction in the toxicity of effluents. Here we quantify the reduction of effluent toxicity potentially achieved by implementing these advanced treatment solutions in a selection of the European wastewater treatment plants. To this end, we refer to a list of “total pollution proxy substances” (TPPS) composed of 1337 chemicals commonly found in wastewater effluents according to a compilation of datasets of measured concentrations. We consider these substances as an approximation of the “chemical universe” impinging on the European wastewater system. We evaluate the fate of the TPPS in conventional and advanced treatment plants using a compilation of experimental physicochemical properties that describe their sorption, volatilization and biodegradation during activated sludge treatment, as well as known removal efficiency in ozonation and activated carbon treatment, while filling the gaps through in silico prediction models. We estimate that the discharge of micropollutants with wastewater effluents in the European Union has a cumulative MP toxicity to the environment equal to the discharge of untreated wastewater of ca. 160 million population equivalents (PE), i.e. about 30 % of the generated wastewater in the EU. If all plants above a capacity of 100,000 PE were equipped with advanced treatment, we show that this load would be reduced to about 95 million PE. In addition, implementing advanced treatment in wastewater plants above 10,000 PE discharging to water bodies with an average dilution ratio smaller than 10 would yield a widespread improvement in terms of exposure of freshwater ecosystems to micropollutants, almost halving the part of the stream network exposed to the highest toxic risks. Our analysis provides background for a cost-effectiveness appraisal of advanced treatment “at the end of the pipe”, which could lead to optimized interventions. This should not be regarded as a stand-alone solution, but as a complement to policies for the control of emissions at the source for the most problematic micropollutants.

Zusammenfassung

Water Research, 104 (2016) 82-92. doi:10.1016/j.watres.2016.07.068

Zusammenfassung

Dieser Beitrag stellt die Ergebnisse einer Messkampagne vor, in der die Belastung des stark urban geprägten Fließgewässers Körsch durch Einträge organischer Spurenstoffe über das Abwassersystem (Kanalnetz und Kläranlage) untersucht wurde. Es wurden 69 Substanzen betrachtet, die repräsentativ für verschiedene chemische und physikalische Eigenschaften sowie für unterschiedliche Eintragspfade sind. Die im Gewässer gemessenen Konzentrationen überschreiten für viele Stoffe die gesetzlich geregelten Umweltqualitätsnormen (UQN). Die Bilanzierung der emittierten Spurenstoffströme über ein Jahr zeigt, dass für 13 Spurenstoffe die Einträge durch Mischwasserentlastungen höher waren als die Emissionen der Kläranlage, obwohl die Entlastungsmenge des RÜB nur 5~\% der gesamten in die Körsch eingeleiteten Abwassermenge betrug. Acht dieser Stoffe sind gesetzlich geregelt. Der gute chemische Zustand gemäß EU-WRRL kann nur durch eine Kombination von Maßnahmen zur Emissionsminderung auf der Kläranlage und an den Entlastungsbauwerken erreicht werden.

Zusammenfassung

The catchment of the river Schwippe is characterized by a high degree of urbanization and industry and the surface water quality is strongly influenced by urban runoff. In July 2011 a water quality monitoring station was installed in the river upstream of the wastewater treatment plant (WWTP). The aim was to describe temporal variations of organic pollutants concentrations in the urban receiving water body and to improve the understanding of pollution dynamics in the urban catchment. The results show that in the course of a storm event the peaks of different micropollutants are shifted in time. This can be explained by their different origin (wastewater, street runoff) and by their physicochemical properties. River water quality during rain events is highly variable and depends on rainfall characteristics, such as rainfall intensity and duration, antecedent dry period and on combined sewer overflow (CSO) activity. Turbidity or total suspended solids are suitable indicator parameters for the assessment of concentrations of particle-bound micropollutants during storm events.

Zusammenfassung

The occurrence of eight selected organic pollutants were monitored for both dry and wet weather conditions in the effluent of a wastewater treatment plant (WWTP) and in the receiving river Schwippe (Germany) upstream and downstream from the WWTP discharge point. These pollutants were detected in all samples in treated wastewater and in the urban receiving water body. Compounds detected in the WWTP effluent samples (n=15) had concentrations ranging from 3 ng/L to 2,190 ng/L. In the surface water samples (n=27), organic pollutants were detected at concentrations ranging from 3 ng/L to 1,260 ng/L. During dry weather, the WWTP effluent was the most important source of organic pollutants in the receiving water. Storm events can have a significant influence of organic pollutants levels in the surface water and should be taken into account when assessing the occurrence of pollutants in surface waters. For the same storm event, the peaks with the highest concentrations for each pollutant are temporally shifted, due mainly to their origin (wastewater, street runoff) and to their physico-chemical properties.