The surplus of nutrients in surface waters due to anthropogenic influences makes eutrophication an important issue in water quality in Europe. According to the Water Framework Directive of the European Union (EU-WFD) an improvement of all water bodies to a “good ecological status” is aimed. One aspect for achieving the goal is an additional reduction of nutrient immissions. In particular, the study has a focus on advanced nitrogen removal at large scale wastewater treatment plants (WWTP) in the area of Berlin and Brandenburg, Germany. A comprehensive life cycle assessment (LCA) of a generic WWTP with 1.47 million population equivalent (pe) is carried out. The WWTP includes a secondary treatment with upstream denitrification. Sludge treatment is realized by anaerobic digestion with biogas utilization and sludge disposal in a mono-incineration plant. On basis of the generic WWTP, five scenarios for an advanced nitrogen removal are analyzed and compared within the LCA: an expansion of the denitrification reactor (ExpDeni), a retrofit to a step-feed nitrogen removal (SFNR), a biologically active filtration (BAF) as post-treatment step as well as two processes for sludge liquor treatment by deammonification (Anammox) and by an SBR-reactor (SBR). Data for energy and chemical demand, effluent quality and infrastructure are based on an existing plant from Berlin and data of nitrogen removal processes on simulations and planning data for this particular WWTP. For the life cycle impact assessment, the following categories are considered: global warming potential (GWP), acidification potential (AP), marine (MEP) and freshwater eutrophication (FEP) as well as human (HTP) and freshwater ecotoxicity (FETP). Additional, the cumulative energy demand (CED) of fossil and nuclear energy resources is taken into account. For the generic WWTP two results have to be emphasized: the influence of high energy demand on potential environmental impacts and the relevance of the primary function of nutrient removal due to a high influence in eutrophication impact categories MEP and FEP. Hence, reducing electricity demand and an increased use of renewable energy resources will lead to reduced impacts. Comparing the nitrogen removal processes, SFNR is preferable to ExpDeni because of reduced energy demand (SFNR: -6%, ExpDeni: +9%) which leads to an improved environmental profile throughout all categories. Focusing on sludge liquor processes, Anammox may be recommended due to mainly lower additional impacts to SBR-process. Main issues at SBR are the high energy consumption (almost twice as high as energy demand of Anammox) and addition of methanol as carbon source. The BAF has the highest impacts in CED (+33%) and GWP (+14%) due to high energy demand for pumping and backwashing (+5%) and methanol dosing. However, favorable side-effects such as a reduction of phosphorus and heavy metal loads lead to a significant reduction in FEP (-18%) and FETP (-9%). All in all, SFNR is recommended in an overall comparison, Anammox has the second best environmental profile. BAF can be recommended if other effects in wastewater treatment are aimed at. Due to lack of data concerning trace organics, uncertainties in toxicity potential are still apparent. Besides, uncertainties in estimating N2O-emission factors have a high effect on the result of GWP. Further investigations on N2O emissions from biological treatment steps should be done to reduce the uncertainties. Finally, LCA is a powerful tool for revealing potential environmental impacts for supporting a sustainable way of decision making process.

To sustain good harvests, about 975,000 tons of mineral phosphorus need to be imported to Europe every year, while the potentials to recover and recycle this essential resource remain untapped or are just inefficiently used as in the case of sewage sludge. In the recent years various technical alternatives to the traditional but disputed application of sludge in agriculture have been developed to recover the nutrient. Especially user friendly solutions have already made their way to full-scale or at least pilot-scale application. National and international initiatives are dedicated to foster the implementation of new solutions, to bridge the gaps between the relevant sectors of science, policy and industry to finally increase the overall anthropogenic phosphorus efficiency according to the motto of the recent First European Sustainable Phosphorus Conference: use less, recycle more and cooperate smart. (www.phosphorusplatform.eu)

Combined sewer overflows (CSO) after heavy rainfall can cause acute depletions of dissolved oxygen (DO) in the Berlin River Spree. Further aggravation of ecological deficits can be expected from global climate change. A planning instrument for CSO impact assessment under different sewer management and climate conditions has been developed at Kompetenzzentrum Wasser Berlin. It couples the sewer model InfoWorks CS, the river water quality model Hydrax/QSim and an impact assessment tool. The planning instrument was validated for the years 2010 and 2011. Simulation results for the critical parameters discharge and DO concentrations in the Berlin River Spree agree well with measurements. Although not all observed DO deficits can be simulated accurately, the very good representation of processes related to the oxygen budget allows assessing relative changes in boundary conditions, e.g. from climate change or different CSO control strategies. The conducted scenario analysis indicates that the coupled sewer-rivermodel reacts sensitively to changes in boundary conditions (temperature, rainfall, storage volume and other CSO control strategies, etc.). Based on the simulation year 2007 – representing an extreme year with regards to CSO volume and critical conditions in the river – sewer rehabilitation measures planned to be implemented until 2020 are predicted to reduce total CSO volumes by 17% and discharged pollutant loads by 21 - 31%. The frequency of critical DO conditions for the most sensitive local fish species will decrease by one third. For a further improvement of water quality after the year 2020, the reduction of impervious surfaces emerges as a very effective management strategy where feasible. A reduction of the impervious connected area by 20% results in a decrease in the frequency of critical DO conditions by another third. The studied increase in surface air and water temperature as part of the climate change scenarios leads to a significant aggravation of DO stress due to background pollution in the Berlin River Spree, while acute DO depletions after CSO are barely affected. However, changes in rain intensity have a considerable effect on CSO volumes, pollutant loads and the frequency of critical DO concentrations. A general reduction of discharged pollutant loads by 60% based on the sewer status 2020 can prevent critical DO conditions in the Berlin River Spree, even for the exceptionally rain intense year 2007. A detailed analysis of river processes after CSO, has shown that the biodegradation of organic carbon compounds is the most important contributor to acute DO depletions in the Berlin River Spree. An additional impairment of DO conditions is caused by the inflow of oxygen free CSO spill water and suspended solids into the Berlin River Spree. In this report, CSO impacts under different management strategies or climate change conditions are assessed only for a part of the Berlin combined sewer system (although the main part) and for one exemplary year. An extension of the planning instrument to the entire combined sewer system would enable to evaluate the full impact of measures. For a robust prediction of future CSO impacts it is also recommended to test different simulation periods or conduct long-term simulations.

A MBBR before an advanced sedimentation step was operated as new wastewater process scheme for maximum COD extraction. The objective of this biological reactor was to modify the soluble COD ratio in primary wastewater. At high loads, the MBBR is able to consume the soluble COD for bacteria activity with very little oxidation. This process changes the soluble COD into particulate COD which is better separate from the wastewater during the following step with coagulation, flocculation and micro sieve filtration. Goals were 95% removal of suspended solids and 80% of COD extracted through separation. To check these new scheme performances, a pilot plant (0.5 to 3 m³/h) was operated at the Stahnsdorf WWTP in the south of Berlin. First results showed that a HRT of 20-30 min and a load 40-60 g CODf /(m2*d) can be recommended for maximum accumulation and minimum oxidation and that the 80% of COD extraction can be achieved (at low oxygen concentration below 1 mg/L). However the performance difference between the scheme with or without MBBR did not exceed 8 %

Die reinigung von Abwasser ist sehr energieintensiv. die kommunale abwasserbehandlung zählt deshalb noch vor Schulen und krankenhäusern zu den größten Stromverbrauchern. in den rund 10.000 deutschen kläranlagen schlummern allerdings erhebliche einsparpotenziale und sogar bislang ungenutzte energieressourcen, die noch erschlossen werden können.

The present study aims at demonstrating the possibilities of on-line sensors for describing CSO emissions and river impacts. A continuous integrated monitoring, using state-of-the-art on-line sensors, was started in Berlin in 2010. It combines (i) continuous measurements of water quality and flow rates of combined sewer overflows (CSO) at one main CSO outlet and (ii) continuous measurements of water quality parameters at four sites within the urban stretch of the receiving river. UV-VIS probes provide continuous measurements of parameters such as chemical oxygen demand (COD) with relatively low uncertainties (10-30%). However, experience shows that on-line UV-VIS probes are not able to provide accurate measurements of water quality without being calibrated to local conditions. Several methodologies to analyze on-line CSO and river measurements are presented and illustrated with an exemplary event. Results show that reliable information such as the CSO load, the proportion of wastewater in CSO, the contribution of wastewater to CSO load, the first flush effect and the intensity of river impacts can be gained at high precision and temporal resolution. Given the broad range of high quality information from CSO impacts in the river to the characterization of CSO emissions, the study suggests the use of continuous integrated monitoring programs to support decisions on CSO management.

Increasing subsurface activities like geothermal energy production, unconventional gas exploitation (EGR – enhanced gas recovery), enhanced oil recovery (EOR) or geological carbon dioxide storage (GCS) are potentially hazardous for the environment. Especially fresh water aquifers used as drinking water resources need to be protected. The first phase of the project COSMA focuses on potential hazards and hazardous events arising from those activities and aims at developing an approach for quantifying and comparing potential risks. A general description of hazards and hazardous events resulting from emerging subsurface activities is given in the first deliverable D1.1 “Geological CO2 Storage and Other Emerging Subsurface Activities: Catalogue of Potential Impacts on Drinking Water Production”. In this 2nd deliverable, reported hazards and hazardous events resulting from geothermal energy production in Germany are described. This report includes analyses of enquiries to experts from all federal states, State Geological Surveys, information from standardization committees, developers, planners, drilling contractors, expert committees, consulting engineers and regulatory authorities such as environmental agencies, water authorities and mining authorities as well as from media reports. It aims to list and categorize observed impacts arising from recent geothermal projects, as there have been increasing activities in this field in the past 10 years in Germany and because there are many similarities to other subsurface activities with respect to drilling processes, fracking methods and reinjection of fluids. The German classification of geothermal systems distinguishes between shallow or nearsurface (< 400 m depth) and deep geothermal energy (> 400 m depth) systems, which will be used in the following chapters. Table 1 shows the difference to international classification schemes, regarding enthalpies and temperatures. The reported case studies of failures potentially leading to contamination of freshwater aquifers are described in chapter 2 with respect to the setting and the reason for failure (if known). Chapter 3 gives some recommendations with respect to possible precautions and countermeasures to prevent such potentially hazardous events. Regardless of the drilling depth there are general hazards and hazardous events that must be taken into account for all subsurface activities. Amongst these are hazardous events during operation which can lead to a contamination of the site, hazardous events during drilling caused by wrongly selected drilling techniques, drilling into unknown caverns, cavities or caves or faulty casing, construction or plugging (sealing). Furthermore, unexpected chemical reactions between fluids and casing or sealing material (e.g. grout) can cause seepage or leakage and therefore hydraulic short circuits. Table 2 gives a summary of general impacts of drilling, especially when multiple aquifers are intersected, as well as from operation of geothermal facilities. Further details are given in COSMA-1 report D 1.1.

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.