In den letzten Jahren wurde eine steigende Anzahl organischer Spurenstoffe wie beispielsweise Medikamente, Industriechemikalien, usw. im Wasserkreislauf detektiert. Kommunale Kläranlagen stellen dabei einen wichtigen Eintragspfad solcher Stoffe in die Oberflächengewässer dar, weswegen dort ein vermehrter Ausbau der sogenannten 4. Reinigungsstufe zur Elimination der Spurenstoffe durch den Einsatz von Aktivkohle und/oder Ozon stattfindet. Für den praktischen Betrieb einer Ozonanlage sind dabei Aspekte wie Überwachung der Spurenstoffelimination sowie eine bedarfsgerechte Anpassung der Ozondosis an eine variierende Wasserqualität von großer Bedeutung. Praxiserfahrungen der letzten Jahre haben dabei gezeigt, dass der Einsatz von UV-Sonden zur Bestimmung des SAK254 bzw. dessen relative Abnahme durch die Ozonung (delta SAK254) sowohl zur Betriebsüberwachung als auch zur Regulierung der Ozondosis geeignet ist [1], weswegen die Ermittlung des delta SAK254 ergänzend zu einer periodischen Überprüfung der Spurenstoffelimination seitens des Verbands der Schweizer Abwasser- und Gewässerschutzfachleute (VSA) empfohlen wird [2]. Als mögliche Alternative zur Verwendung des SAK254 wird der Einsatz von Fluoreszenzsonden diskutiert, da die Abnahme der Fluoreszenz durch die Ozonung ebenfalls eine Korrelation mit der Elimination von Spurenstoffen aufweist [3]. Derzeit werden Fluoreszenzmessungen beispielsweise zur Detektion von Algenblüten in Seen oder zur Überprüfung von Öl im Wasser eingesetzt, wohingegen nur wenige Erfahrungen zum Einsatz bei Ozonanlagen auf Kläranlagen vorliegen. Im Rahmen dieses Beitrags werden Praxiserfahrungen einer Fluoreszenz-Onlinemessung im Einsatz auf einer Ozonanlage zur Spurenstoffelimination auf Kläranlagen vorgestellt und Vor- bzw. Nachteile gegenüber einer SAK254-Onlinemessung hinsichtlich der Sensitivität, bezüglich Änderungen der Wassermatrix, Einfluss von Fouling sowie Wartungsaufwand herausgearbeitet.

In the recent years, an increasing number of organic micropollutants (OMPs) such as pharmaceuticals, industrial chemicals etc. have been detected within the water cycle. Conventional municipal wastewater treatment plants (WWTPs) are an important entry path of OMPs into the surface waters, as they can only partly eliminate OMPs. Thus, advanced wastewater treatment options such as activated carbon and/or ozonation can be used to reduce the amount of OMPs entering the receiving waters. Especially for the operation of an ozonation plant, aspects such as monitoring of the OMP elimination as well as an adaption of the ozone dose to a varying water quality are of great importance. Practical experiences in the last years have shown that the reduction of UVA254 (delta UVA254) by the ozonation can be used for the regulation of the ozone dose [1] and to monitor the ozonation process as it is recommended by the Swiss Water Association (VSA) in addition to a periodic measurement of the OMP elimination [2]. As an alternative to UVA254, usage of fluorescence online sensors have been also in discussion as its decrease due to the ozonation process also shows a good correlation with the OMP elimination [3]. Currently, fluorescence online measurements are used for detecting algae blooms in lakes or oil in water. However, practical experiences of the operation of fluorescence online sensors at ozonation plants used for OMP elimination are limited. Within this presentation results of the operation of a fluorescence online measurement at an ozonation pilot plant will be shown and compared to the operation of a UVA254 online measurement regarding sensitivity, impact of the water matrix, fouling effects as well as maintenance efforts.

NextGen aims to boost sustainability and bring new market dynamics throughout the water cycle at the 10 demo cases and beyond. Main objective of WP1 of the project is to provide evidence to demonstrate the feasibility of innovative technological solutions supporting a circular economy transition in the water sector. Through activities to close the water, energy and materials cycles in 10 demo cases, Work package 1 (WP1) will provide the necessary data to assess the benefits and drawbacks of the technologies (WP2), but also to provide evidence to convince stakeholders on their implementation (WP3), while overcoming the social and governance barriers and creating new business models to promote the implementation of those solutions (WP5 & WP6). This report describes the baseline conditions of each of the sites involved in the project considering water, energy and material cycles. The baseline of the 10 sites (Altenrhein, Athens, Braunschweig, Bucharest, Costa Brava, Filton Airfield, Gotland, La Trappe, Spernal and Westland region) will be used at the end of the project so to define the improvement and/or drawbacks and benefits associated to the implementation of the NextGen solutions. This report corresponds to the first deliverable of the WP1, envisaged for June 2019, and complements the information collected for milestone MS3 on Methodology and specific objectives defined for each case study. All the information of this report has been collected by the Cross-cutting Technology Group (CTG) Leaders since July 2018 through regular discussions with the different case study representatives and through different templates that have been prepared and compiled. Baseline of each case study has been defined for each of the nexus of NextGen project using key performance indicators (KPIs) linked to water, energy and materials. Potential interlinkages between case studies are also described in this document, aiming at increasing the uptake and impact of the NextGen solutions.

Die Häufung der Befunde von Arzneimittelrückständen in Oberflächengewässern in Deutschland und weltweit, stellen eine aktuelle Gefährdung der stark belasteten städtischen Oberflächengewässer, als aquatisches Ökosystem und unentbehrliche Ressource zur Trinkwassergewinnung, dar. Als eine der bedeutendsten Eintragspfade in Oberflächengewässer gelten die Abläufe kommunaler Kläranlagen. Grund dafür ist, dass die oft persistenten und bioakkumulierenden Stoffe durch den konventionellen Klärprozess nicht aus dem Wasser entfernt werden können. Auch die verschärften Bestimmungen gegenüber den einzuhaltenden Wasserqualitätsparametern, wie Nährstoffgehalt oder Keimkonzentrationen, die sich aus der Umsetzung der EU-Wasserrahmenrichtlinie sowie der EU-Badegewässerrichtlinie ergeben, können voraussichtlich nur durch die Einführung einer 4. Reinigungsstufe eingehalten werden. Ein steigender Arzneimittelgebrauch, beschleunigt durch den demographischen Wandel, sowie eine geringere Verdünnung des gereinigten Abwassers aufgrund der erwarteten klimatischen Veränderungen, unterstreichen die Notwendigkeit einer 4. Reinigungsstufe mit dem Ziel einer weitergehenden Spurenstoffelimination. Die vorliegende Arbeit wurde in der Firma „Kompetenzzentrum Wasser Berlin gGmbH“ (KWB) im Zuge der Mitarbeit im EU-Forschungsprojekt „AquaNES“ am Versuchsstandort „Klärwerk Schönerlinde“ verfasst. Die auf dem Betriebsgelände der Berliner Wasserbetriebe (BWB) betriebene zweistufige Pilotanlage besteht aus einer Ozonung sowie einer nachgeschalteten biologischen Behandlung durch zwei parallel betriebene bepflanzte Bodenfilter (BF). Bodenfilter 1 (BF 1) wurde als klassischer Sandfilter konzipiert, das Filterbett von Bodenfilter 2 (BF 2) besteht aus einem kiesigen Lava-Biokohle-Gemisch. In der vorliegenden Arbeit wurde die Reinigungswirkung der vertikal durchströmten BF bestimmt, verglichen und bewertet. Diese wurde anhand der, zwischen Zu- und Ablauf, gemessenen Differenz verschiedener Wasserqualitätsparameter (WQPM), der Konzentration relevanter Abwasserkeime sowie ausgewählter Spurenstoffe untersucht. Im besonderen Fokus standen dabei die durch die BF erzielbare Spurenstoffelimination sowie der Rückschluss auf die jeweils verantwortlichen Prozesse im Filterbett. Als Grundlage der Analyse wurden die laboranalytischen Rohdaten von 60 Probenahmeterminen, die über einen 20-monatigen Beprobungszeitraum (Mai 2017 - Dez. 2018) bestimmt wurden, verwendet. Zusätzlich wurden eigene praktische Untersuchungen zur genaueren Bestimmung der gelösten Sauerstoffkonzentration im Filterbett der BF unternommen. Es konnte eine zusätzliche Reinigungsleistung der beiden BF gegenüber fast allen betrachteten Parametern, gezeigt werden. Für das Gesamtverfahren aus Ozonung und bepflanzten BF wurde eine Verbesserung für ausnahmslos alle untersuchten Parameter aus den Kategorien Wasserqualität, Mikrobiologie und Spurenstoffe erreicht. Für die untersuchten WQPM: CSB, BSB5, DOC, Nitrat, organischer Stickstoff, AFS und Trübung zeigte BF 2 eine höhere bzw. gleichstarke Reinigungsleistung. Auch die betrachteten Spurenstoffe CBZ, DCF, BTA, MTP und OXP wurden durch BF 2, aufgrund des adsorptiven Rückhalts an der Biokohle, effektiver eliminiert. Nur CLA wurde besser durch BF 1 reduziert. TCPP wurde durch beide BF etwa gleichgut zurückgehalten. BF 1 zeigte dagegen deutlich höhere Effektivität bei der Reduktion aller betrachteten Abwasserkeime (E. Coli-, Enterokokken-, C. Perfringens- und somatische Coliphagen). In den BF wurden biologischer Abbau, Adsorption in BF 2 sowie Filtration als hauptsächliche Eliminationsprozesse ausgemacht.

The present work deals with the possibility of using capillary nanofiltration (NF) in combination with bank filtration as a pretreatment step for drinking water production. Main goal is to show the removal of selected compounds including sulphate and organic micropollutants (OMP) during the NF. Also demonstrating the benefits of bank filtration as a pretreatment step in comparison to the direct treatment of surface water using capillary NF. For that purpose, a demonstration site in pilot scale was operated as a part of the European project AquaNES at the waterworks Tiefwerder in Berlin. Since 2017 several studies (Hoff, 2017; Rohde, 2018; Jährig et al., 2018) were conducted with drinking water and anoxic well water as feed sources for the NF pilot plant. Building on these the main objective of the present thesis is to optimize the NF pilot plant operation using suboxic well water and surface water as a feed source. Operating data was analyzed and sampling campaigns were carried out to determine the retention capacity of the capillary NF membranes for selected compounds. High retention was achieved for sulphate (45 - 67 %), hardness (55 %), iron (80 %) and selected OMPs further with removal of DOC (56 – 88 %). Microbiological sampling showed a higher impact of microbial growth during the operation of the pilot plant with surface water compared to well water. Furthermore different cleaning agents were tested concerning their ability to restore the membrane performance and their costs. Regarding the specific energy consumption, different measures showed a reduction of plant energy need can be achieved. In conclusion the experiments show a higher impact of biofouling during the direct surface water treatment in comparison to the pretreatment with bank filtration. Long term operation of the tested capillary NF is possible. Under the influence of oxygen and microbial growth there is a high demand of chemical cleaning.

Wastewater treatment (WWT) is obligatory for the protection of ecosystems and human health but also produces the greenhouse gases (GHGs) nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2 ) along the process chain. According to the IPCC (2018) anthropogenic CO2 and carbon emissions must decline by 45% worldwide from 2010 levels by 2030 to keep temperatures from rising beyond 1.5 ° degrees. Currently the sector of WWT contributes about 0.11 % to the total carbon emissions in Germany and was responsible for about 5 % of global non-CO2 GHG emissions in 2005. N2O emissions in particular play the major role here. Aerobic granular sludge (AGS) for biological WWT has gained increasing interest mainly due to higher process efficiency compared to conventional activated sludge (CAS). Studies show a reduction potential of 20 – 25 % in operation costs, 23 – 40 % in electricity use and 50 –75 % in space requirements. AGS processes are implemented as sequencing batch reactor (SBR). SBRs with a small temporal and spatial variability for biological metabolism are likely to generate process conditions promoting N2O formation. A 1% increase in direct N2O emissions could already result in a 30 % increase of the carbon footprint of a WWTP. In this thesis direct GHG emissions from AGS treating domestic wastewater are studied. It was part of the project E-VENT where an AGS Nereda® pilot-plant has been operated at Stahnsdorf WWTP, Berlin (Germany). The reactor was fully-covered and GHG emissions have been monitored online over a 3 months period. A conservative approach for off-gas flow determination has been chosen to not over-estimate GHG loads. The plant was operated with domestic wastewater extracted after the primary clarifiers. At stable operating conditions maximum removal rates of 96 % chemical oxygen demand, 90 % nitrogen and 87 % phosphorous were achieved. Determined emission factors (EF) for N2O and CH4 over the complete measurement period were 2.86 % and 0.18 % respectively. Rising process temperatures from 13 – 20 °C showed a positive correlation with EFs and higher TN loads during the day lead to higher N2O complementing literature review on N2O EFs. The CO2 EFs showed that determined values for AGS are in accordance with 2.8 % ± 1.2 % found in a comparable study by Guimarães et al. (2017). Findings conclude that N2O contributes to about 95 % to total direct carbon emissions of the Nereda® plant and is a main factor for the climate impact of AGS.

Fecal indicator organisms such as Escherichia coli, enterococci, and coliphages are important to assess, monitor, and predict microbial water quality in natural freshwater ecosystems. To improve predictive modelling of fecal indicators in surface waters, it is vital to assess the influence of autochthonous and allochthonous environmental factors on microbial water quality in riverine systems. To better understand how environmental conditions influence the fate of fecal indicators under varying weather conditions, the interdependencies of environmental parameters and concentrations of E. coli, intestinal enterococci, and somatic coliphages were studied at two rivers (Rhine and Moselle in Rhineland-Palatinate, Germany) over a period of 2 years that exhibited contrasting hydrological conditions. Both riverine sampling sites were subject to similar meteorological conditions based on spatial proximity, but differed in hydrodynamics and hydrochemistry, thus providing further insight into the role of river-specific determinants on fecal indicator concentrations. Furthermore, a Bayesian multiple linear regression approach that complies with the European Bathing Water Directive was applied to both rivers’ datasets to test model transferability and the validity of microbial water quality predictions in riverine systems under varying flow regimes. According to multivariate statistical analyses, rainfall events and high water discharge favored the input and dissemination of fecal indicators in both rivers. As expected, concentrations declined with rising global solar irradiance, water temperature, and pH. While variations in coliphage concentrations were predominantly driven by hydro-meteorological factors, bacterial indicator concentrations were strongly influenced by autochthonous biotic factors related to primary production. This was more pronounced under low flow conditions accompanied by strong phytoplankton blooms. Strong seasonal variations pointed towards bacterial indicator losses due to grazing activities. The Bayesian linear regression approach provided appropriate water quality predictions at the Rhine sampling site based on discharge, global solar irradiance, and rainfall as fecal indicator distributions were predominantly driven by hydro-meteorological factors. Assessment of microbial water quality predictions implied that rivers characterized by strong hydrodynamics qualify for multiple linear regression models using readily measurable hydro-meteorological parameters. In rivers where trophic interactions exceed hydrodynamic influences, such as the Moselle, viral indicators may pose a more reliable response variable in statistical models.