This project report summarizes work conducted in work package 11. Along with the deliverable 11.1 and milestone report 11 it covers the tasks from work package 11 as formulated in the Description of Work (DoW). The content of the different sections is interrelated, but each section is organized as an independent part. Title of this report differs from DoW because recommendations for optimum design and operation will be handled in the deliverable 12.2. The sections in this report cover various topics and each section can be found as a stand-alone report in the DEMEAU tool box (http://demeaufp7.eu/toolbox/) for download. Detailed summaries can be found for each section separately.

The Australian Guidelines for Water Recycling – Managed Aquifer Recharge provide a ready-to -use and user-friendly compendium of knowledge. Practical instructions and checklists provide a step wise approach with a strong focus on implementation. The proposed models for water flow and substance transport allow a first tier estimation of present concentrations in ambient groundwater and the impacted zone in the aquifer. The use of stochastic models is not mandatory within the guidelines. A criticism which can be identified related to the use of models simply based on point estimates, is that especially in early stage risk assessments, where uncertainties are usually high, these models tend to pretend a level of certainty which often does not represent reality. Risks associated to inorganic chemicals are required to be treated with more detail. Rigorous quantification of biodegradation kinetics (e.g. first-order rate constants) and adsorption parameters (e.g. linear distribution coefficients) for EOCs during subsurface passage determined on field scale are still scarce. It is clear that first-order rate constants and linear distribution coefficients provide only a simplified description of the removal mechanisms during subsurface passage, because they neglect spatial and temporal dynamics of physical and chemical conditions. Nevertheless, this approach often provides a good approximation and allows also for site independent comparison of removal processes. Regarding the demonstration site in Berlin-Tegel the analysis showed that if the model of the Australian Guidelines is applied to the MAR system the travel time of 50d during subsurface passage cannot be guaranteed. In Germany, a residence time of 50d is usually considered to sufficiently reduce the risk of microbial hazards. Although risk calculations did not reveal immediate concern, it is recommended to develop and apply suitable verification monitoring techniques to quantify travel times and reduce present uncertainties. Moreover, this risk assessment and the study about the influence of the groundwater replenishment site on ambient groundwater (Sprenger and Grützmacher, 2015) clearly showed the need for protective measures against the input of undesired substances from shallow ambient groundwater.

Das vorliegende Dokument ist als zusammenfassender Synthesebericht des Forschungsprojektes RIKO-1 konzipiert und ergänzt die fünf Teilberichte zu den Arbeitspaketen aus RIKO-1 mit einer versuchsübergreifenden Betrachtung, Diskussion der Ergebnisse und Schlussfolgerungen zur Risikominimierung. Ausgehend von den in den Teilberichten dokumentierten Recherchen und Versuchen werden dazu in Kapitel 2 zunächst der Kenntnisstand zu Beginn des Projektes zusammengefasst und ein Überblick über die Untersuchungen gegeben. Kapitel 3 unterzieht die Brunnen einer Gefährdungsanalyse und beschreibt mögliche Eintragspfade und Einflussfaktoren mit einer Bewertung der Eintrittswahrscheinlichkeiten. Die vorliegenden Daten werden in Kapitel 4 dann in eine Risikoanalyse überführt und auf Basis der Priorisierung der Gefährdungsereignisse Maßnahmen zur Minimierung von Befunden empfohlen. Indikatorkeime, ihre Überwachung sowie der Stand von Forschung und Entwicklung neuer (molekularbiologischer) Methoden zur Analyse und Früherkennung bzw. Möglichkeiten der Online-Überwachung werden im Teilbericht "Mikrobiologische Methoden: Stand der Technik" von O. Thronicker behandelt. Die deskriptive Datenanalyse vorliegender Befunddaten hinsichtlich möglicher Zusammenhänge mit bestimmten Brunneneigenschaften, insbesondere Lage, Baumerkmalen und Betriebsparametern wurde im Teilbericht "Deskriptive Datenanalyse" zusammengefasst. Die Feldversuche im Rahmen der Einzelbrunnenuntersuchung SPAsued10, die Markierungsversuche an zwei Brunnen im Wasserwerk Jungfernheide sowie die Sediment- und Wasserbeprobungen an einer Transekte entlang des Fließpfades des Uferfiltrats von der Havel zur Galerie Tiefwerder-Schildhorn sind in den entsprechenden Teilberichten dokumentiert. Die Teilberichte beschreiben jeweils die Ausgangslage zu Versuchsbeginn, die Methodik und Ergebnisse und enthalten eine ausführliche Diskussion und Schlussfolgerungen aus den Versuchen. Der hier vorliegende Synthesebericht greift die einzelnen Versuche und Ergebnisse in der Beschreibung des Kenntnisstandes nach dem Konzept eines Water Safety Plans (WSP, WHO 2009) auf. WSPs auf Wasserwerksebene wurden bislang von den BWB für sechs der neun aktiven Wasserwerke im Entwurf erstellt. Sie fokussieren auf die Aufbereitungsschritte vom Rohwasser zum Reinwasser. In RIKO-1 sollte ergänzend vor allem der Einzelbrunnen betrachtet werden. Die Risikobewertung bezieht sich daher auf die Wassergewinnung, d.h. den Weg des Wassers vom zur Uferfiltration genutzten Oberflächengewässer bis zum Eintritt des Rohwassers in die Sammelleitung. Die davor (Ressourcenschutz) und danach (Rohwasseraufbereitung) liegenden Teile des teilgeschlossenen Wasserkreislaufs werden nicht behandelt. Die ganzheitliche Betrachtung und Entwicklung eines WSPs für den gesamten Berliner Wasserkreislaufs ist Ziel im Projekt ASKURIS. Als weitere Grundlagen der Arbeiten in RIKO-1 und der zusammenfassenden Betrachtung im vorliegenden Bericht dienten u.a. das Wasserversorgungskonzept 2040 (Möller & Burgschweiger 2008), eine Fallstudie der Befunde 2003-2007 in WELLMA-1 (Gräber 2009, unveröffentlicht) sowie Forschungsarbeiten aus NASRI und IC-NASRI (Lopez-Pila & Szewzyk 2006; u.a.). Alle geplanten Untersuchungen und Zwischenergebnisse wurden regelmäßig im Projektteam diskutiert (vgl. Besprechungsprotokolle) und daraus folgend ggf. Maßnahmen zur direkten Umsetzung abgeleitet oder Versuchskonzepte angepasst. Ein Verzeichnis der in Ergänzung zum Synthesebericht vorliegenden Berichte und Protokolle, auf die im Weiteren verwiesen wird, findet sich in Anhang 1.

Risk-based management approaches are more and more used in the water sector and are promoted by the WHO. As a first step towards an overall risk-based management approach of the agricultural wastewater reuse concept of Braunschweig a quantitative microbial risk assessment (QMRA) is conducted. A 1000 trial Monte Carlo Simulation is used for the assessment of microbial risks for fieldworkers and nearby residents. As a tolerable value of risk an additional disease burden of 1 µDALY is set following the current WHO guidelines. Concerning microbial risks risk-based targets are set in terms of additional required pathogen reduction in the STP Steinhof. Based on the model results an additional reduction of 1.5log units is derived for viruses, for which the highest annual risks of infection per person per year (pppy) is calculated in all scenarios.

Risk-based management approaches are more and more used in the water sector and are promoted by the WHO. As a first step towards an overall risk-based management approach of the agricultural wastewater reuse concept of Braunschweig this report conducts quantitative microbial risk assessment (QMRA) and quantitative chemical risk assessment (QCRA) of heavy metals. Scenarios for microbial risks are conducted for fieldworkers, nearby residents and children ingesting soil using a 1000 trial Monte Carlo Simulation. As a tolerable value of risk an additional disease burden of 1 µDALY is set following the current WHO guidelines. For heavy metals impacts on the terrestrial and aquatic ecosystems as well as on human health are assessed using the methods outlined in the European Union Technical Guidance Document on Risk Assessment (TGD). Concerning microbial risks risk-based targets are set in terms of additional required pathogen reduction in the STP Steinhof. Based on the model results an additional reduction of 1.5log units is derived for viruses, for which the highest annual risks of infection per person per year (pppy) is calculated in all scenarios. Concerning heavy metals the model indicates an increasing tendency of soil concentrations over time and identifies Cd as the only metal which is currently of concern. Risk reduction measures should be considered for this metal. Recommendations are given concerning necessary validation and additional monitoring for eliminating uncertainties within the model.

Risk-based management approaches are more and more used in the water sector and are promoted by the WHO. As a first step towards an overall risk-based management approach of the agricultural wastewater reuse concept of Braunschweig this thesis conducts quantitative microbial risk assessment (QMRA) and quantitative chemical risk assessment (QCRA) of heavy metals. Scenarios for microbial risks are conducted for fieldworkers, nearby residents and children ingesting soil using a 1000 trial Monte Carlo Simulation. As a tolerable value of risk an additional disease burden of 1 µDALY is set following the current WHO guidelines. For heavy metals impacts on the terrestrial and aquatic ecosystems as well as on human health are assessed using the methods outlined in the European Union Technical Guidance Document on Risk Assessment (TGD). Concerning microbial risks risk-based targets are set in terms of additional required pathogen reduction in the STP Steinhof. Based on the model results an additional reduction of 1.5log units is derived for viruses, for which the highest annual risks of infection per person per year (pppy) is calculated in all scenarios. Concerning heavy metals the model indicates an increasing tendency of soil concentrations over time and identifies Cd as the only metal which is currently of concern. Risk reduction measures should be considered for this metal. Recommendations are given concerning necessary validation and additional monitoring for eliminating uncertainties within the model.