According to the European Water Framework Directive, ‘good ecological and chemical status’ must be achieved for all surface waters by 2015 (European Parliament, 2000). Therefore, it is important to extend knowledge on pollutants that run off with urban rainwater. This study has the objective to determine which micropollutants occur in Berlin’s urban rain water run-off and how the most detrimental pollutants can be managed in a sustainable manner to reduce their impact on receiving waters. To reach these objectives, five catchments with different land use characteristics that together represent Berlin were selected for the collection of rainwater samples. These catchments consisted of New buildings (New), Old buildings (Old), One family homes (Ofh), Commercial buildings (Com) and Streets (Str). Actual sampling was done by installing an automated water sampler at each location, together with a flow measuring device to start the sampler during rain events. The following number of rain events were sampled and analysed; New (n=8), Old (n=7), Ofh (n=6), Com (n=11) and Str (n=4). Samples collected during rain events were processed to one volume proportional composite sample that represents the entire event. This sample was then analysed on the presence and concentration of micropollutants. With that information, measures where determined that can be applied for the reduction of pollutant loads. Micropollutants from the following groups were found during this study; pesticides / biocides, industrial chemicals, PAH’s, heavy metals, tracers, flame retardants and phthalates. From these groups, the most detrimental are; Nickel, Diuron, Isoproturon, Cadmium, Lead, PFOA, PFOS , polycyclic aromatic hydrocarbons (PAH), Nonylphenol, DEHP, Zinc, Copper, TCPP, Mecoprop, Glyphosphat, OHBT and Di-iso-decylphthalat. To assess measures for micropollutant reduction, the concept of source-path-threatened object was used to identify where pollutants come from and what pathway they follow to which vulnerable objects. Possible measures to reduce the load of these substances are banning or substituting the pollutant by legislation. Furthermore, vegetation infrastructure, decentralized pre-treatment, infiltration and sedimentation can be applied for reduction of pollutant loads. These measures should be applied in an integrated manner to enhance one another. Pollutant characteristics -and thus behaviour in the environment- is one of the most relevant criteria for the selection of measures to reduce these substances. The most effective approaches for particle and non-particle bound pollutants are end-of-pipe solutions. These consist of sedimentation systems for particle bound, and infiltration structures for non-particle bound micropollutants. Emitting sources (e.g. traffic) and paths (e.g. air) that contribute to pollutants in urban rainwater run-off are further relevant criteria. These can only be directly reduced by legislation, vegetation infrastructure can however be applied to reduce the mobility of these pollutants.

Der Regenwasserabfluss von versiegelten Flächen kann zu erheblichen Beeinträchtigungen von Flüssen und Seen führen. Durch das schnelle Ableiten des Regenwassers bleibt das positive Potenzial für die Stadtbevölkerung und die Umwelt zudem oft ungenutzt. Für eine nachhaltige Regenwasserbewirtschaftung stehen eine Vielzahl von Maßnahmen auf Gebäude-, Quartiers- und Kanaleinzugsgebietsebene zur Verfügung. Im laufenden BMBF-Projekt KURAS werden diese Maßnahmen hinsichtlich Ihrer stadträumlichen, klimatischen, ökologischen und ökonomischen Effekte umfassend untersucht. Daraus werden Empfehlungen für Planer und Behörden für den Umgang mit Regenwasser im städtischen Raum abgeleitet. Beispielhaft für den verfolgten Bewertungsansatz werden im vorliegenden Beitrag Indikatoren vorgestellt, mit denen die Maßnahmeneffekte auf drei ausgewählte Wirkungsbereiche (Biodiversität, Grundwasser und Oberflächengewässer) quantifiziert werden können. Erste Ergebnisse zeigen bereits, wie unterschiedlich Maßnahmen wirken können und wie wichtig die Berücksichtigung lokaler Schutz- und Entwicklungsziele bei der Maßnahmenauswahl ist. Aus der starken Streuung einzelner Bewertungsindikatoren kann zudem ein bedeutender Einfluss von Standortfaktoren und der konkreten Umsetzung einer Maßnahme abgeleitet werden, der bei der Planung ebenfalls berücksichtigt werden sollte.

Zum Erzielen guter Erträge in der Landwirtschaft und in Ermangelung nennenswerter fossiler Vorkommen müssen alljährlich ca. 1 Million Tonnen mineralisch gebundenen Phosphors nach Europa importiert werden. Gleichzeitig werden Rückgewinnungs- und Recyclingpotentiale dieser lebenswichtigen Ressource nicht bzw. wie im Falle des Klärschlamms nur zu einem geringen Anteil genutzt. In den letzten Jahren wurden zahlreiche technische Verfahren entwickelt, die dazu beitragen sollen, den Nährstoff Phosphor alternativ zur umstrittenen Praxis der Klärschlammausbringung wieder für die Landwirtschaft verfügbar und nutzbar zu machen. Insbesondere praxisnahe Lösungen haben bereits den Sprung in die großtechnische Umsetzung geschafft bzw. stehen kurz davor. Nationale wie internationale Initiativen widmen sich dem Zusammenbringen von Akteuren aus Wissenschaft, Politik und Wirtschaft, um die Implementierung voranzubringen. Für ein Nährstoffrecycling genügt es nicht, bei der Nährstoffrückgewinnung aufzuhören. To sustain good harvests, about one million tons of mineral phosphorus have to be imported to Europe annually, 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 pilotscale application. National and international initiatives are dedicated to bridge the gaps between the relevant sectors of science, policy and industry to finally foster wide-spread implementation of phosphorus recovery and recycling. It is not enough to just recover nutrients. To achieve real recycling, the gap between recovery and return of phosphorus into the nutrient cycle needs to be closed. The supply side needs to match with the requirements of the demand side.

Durch das EU-Forschungsprojekt P-REX soll die Implementierung und Verbreitung technischer Phosphorrückgewinnungsverfahren vorangetrieben werden. Langfristiges Ziel ist die EU-weite Umsetzung von effektiver und nachhaltiger Phosphorrückgewinnung und Recycling aus dem Abwasserpfad, wobei regionale Bedingungen und Bedarfe berücksichtigt werden sollen. Bei den Phosphor-Rückgewinnungsverfahren wird der Phosphor in den meisten Fällen mittels chemischer beziehungsweise biologischer Eliminationstechniken zunächst in eine feste Phase, den Klärschlamm, überführt. Hierbei kommt es zu einer deutlichen Aufkonzentration des Phosphors. Dies ist für die Effizienz einer anschließenden Rückgewinnung entscheidend. Unterschieden werden können zunächst Verfahren, die den Phosphor aus dem Klärschlamm zurückgewinnen, und Verfahren, die den Phosphor aus der Asche im Anschluss an die Monoverbrennung zurückgewinnen. Bei der Rückgewinnung aus Klärschlamm kann zwischen den Verfahren mit direkter P-Fällung und den Verfahren mit chemischer Rücklösung und anschließender P-Fällung unterschieden werden. Bei der Rückgewinnung aus Klärschlammaschen kann zwischen nasschemischen Aufschluss-/Leachingverfahren und thermochemischen Verfahren unterschieden werden. In diesem Beitrag werden die verschiedenen Rückgewinnungsverfahren mit den wichtigsten Verfahrensansätzen und Prozessschritten vorgestellt und bewertet.

Energy and resource recovery from raw municipal wastewater is a pre-requisite for an efficient and sustainable wastewater treatment in the future. This paper evaluates several processes for upgrading existing wastewater treatment plants or new concepts towards energy positive and resource efficient wastewater treatment in their life-cyle impacts on the energy balance. In addition, future challenges for integrating both energy and resource recovery in wastewater treatment schemes are identified and discussed.

This report compiles the results of three consecutive work packages that have been worked on during the Aquisafe II project. The approach developed is based on the previous Aquisafe I project where the Soil Water Assessment Tool (SWAT) was used as an analytical instrument to develop mitigation strategies for N loads and concentrations in the Ic catchment. During Aquisage I we concluded that SWAT should include a wetland function with which the effect of artificially, constructed wetlands on solute N fluxes can be evaluated. Chapter 1 compiles results of an extensive literature review that was made to identify potential wetland routines and processes that can be included in SWAT. The SWAT add-on to be developed should allow to individually test the effect on single wetlands (e.g. in a given hydrological response unit or subcatchment) as well as the effect of multiple wetlands on the landscape scale. We therefore implemented a stand alone version of the new wetland module which is described in Chapter 2. Here we show the general functionality and individual components of the wetland module. The chapter ends with a virtual application of the modules using SWAT outputs copied from the Ic results. Additionally, a Monte Carlo based sensitivity analyses of the wetland module input parameters showed that the denitrification rate seems to be the most constrained parameter for the simulation of N turnover in the new wetland module. A full implementation of the new wetland module is described in chapter 3. Here, the structural embedment of the wetland module in the SWAT architecture is described. To proof the functionality of the SWAT wetland module model runs were compared to the stand alone version to make sure that the module was correctly implemented. We conclude that the SWAT wetland extension is ready to be tested in real world catchments. Such a full test of the SWAT wetland model was planned towards the end of Aquisafe II. However, as data from the wetlands constructed within Aquisafe II were not available in due time, this last test of the SWAT module was possible.

In Germany 35% of the total energy consumption in water utilities is due to well pumping (Plath et al., 2010). Therefore, a more efficient abstraction, besides the reduction of the carbon footprint, will lead to economic benefits for the operator. Different strategies exist for energy saving both in the operation of well fields as well as with the use of adapted, energy-efficient technical equipment (pumps, pipes, etc.) (Madsen et al., 2009). The objective of this study is the development and testing of a well field optimization tool, which is based on a hydraulic pipe network model (EPANET) but also takes steady-state well drawdown into account. The optimizer, based on coupling EPANET with the programing language R, simulates automatically the different optimization strategies (e.g. smart well field management, pump renewal) and evaluates their impact on the energy demand. The developed well field model was tested for a case study in France and predicted the measured energy demand with an error of less than 2%. The identified energy saving potential found by the optimizer reaches up to 17% in case of implementing only smart well field management and close to 50% combining the latter option with pump renewal.

Sludge treatment and disposal is one of the key positions of operating costs in large wastewater treatment plants (WWTPs). On large WWTPs, dewatering of digested sludge is mainly performed with centrifuges. The performance of the centrifuge and thus, the (cost-)efficiency of the whole sludge dewatering process, strongly depends on the operating parameters of the centrifuge and the properties/preparation and dosage of the polymer used as flocculation aid. The research project “Decamax” therefore mainly focuses on these aspects and their impact on the dewatering result, i.e. mainly the dry solid content of the sludge cake and the quality of the sludge liquor. Moreover, the impact of sludge pre-heating on sludge dewatering is assessed, because it is known that the dewatering temperature has a high influence on the process as well. Besides a technical study (Work Package 3) and full-scale trials at a WWTP in Berlin (WP 1), the project included trials with a 0.4 m³/h pilot-scale centrifugation unit in Braunschweig (Work Package 2). The results of this work package (performed by the Institute of Sanitary and Environmental Engineering, Technische Universität Braunschweig (ISWW)) are summarised in this report. Besides the ISWW, the pilot-scale trials were supported and evaluated by the Stadtentwässerung Braunschweig (SE|BS), the KompetenzZentrum Wasser Berlin (KWB) – also responsible for the overall project management and control – and Kläranlagenberatung Kopp (KBK). Moreover, the Decamax project team and technical committee include the Berliner Wasserbetriebe (BWB) and Veolia Wasser. The project is financially supported by Veolia Water and BWB.

Unbehandeltes Abwasser ist ein wertvoller Energieträger. Die hier enthaltenen organischen Stoffe haben so viel chemische Energie, dass sich damit die bisher in der Abwasserbehandlung benötigte Energiemenge komplett kompensieren und sogar noch ein Energieübersch uss erzeugen ließe. Wissenschaftler vom Kompetenzzentrum Wasser Berlin (KWB) haben einen neuen Prozess der Abwasserbehandlung entwickelt und im Pilotmaßstab getestet, um das erhebliche Energiepotenzial im Abwasser besser auszuschöpfen. Das Forschungsprojekt CARISMO ("CARbon IS MOney") hat eine Expertenjury für den Deutschen Nachhaltigkeitspreis nominiert.