In recent years considerable progress has been made in numerical weather prognosis. Special progress has been made in doing local forecasts up to five days of temperature, wind and atmospheric pressure and al so o f the weather det erminant flow s ystems. In contrast, the local prognosis of precipitation (liquid and ice phase) has not been improved. T his circumstance has lead to the DFG p rogram “Quantitative rainfall prognosis”. I t co vers broadly base d activities that ai m on the i mprovement o f t he knowledge on t he pr ocesses of r ainfall f ormation and t heir num erical pr ognosis. The main objective is to improve the routine prognosis of the German Weather Association (DWD). The program covers the modeling of microphysical processes as well as the description of essential meteorological conditions in different temporal and spatial scales. Especially, co nvective c loud sy stems that ar e often responsible for e xtreme r ainfall situations are studied. In a G ermany-wide monitoring campaign in the year 2007 comprehensive measurements are conducted. The gained information and data will be used to improve process description and to support model evaluation. The st udy at hand describes the anal ysis and pr ognosis of temporally (5 m in) and spatially (500 m) highly distributed rainfall data for the Berlin area. The data will be used in the frame of the EVA project of Kompetenzzentrum Wasser Berlin to analyse and evaluate the potential of online rainfall measurement and forecast to support the operation of wastewater pump stations.

Zielstellung des im Rahmen des EVA Projekts durchgeführten Arbeitspaketes 3 war die Entwicklung eines Optimierungsmodells des Berliner Abwassersystems, bestehend aus Kanalnetzen, Abwasserdruckleitungsnetz und Kläranlagen, sowie die Implementierung des Modells im algebraischen Modellierungssystem GAMS (General Algebraic Modeling System). Auf dieser Basis sollten mittels mathematischer Optimierung Strategien zur Steuerung der Abwasserströme innerhalb des Abwasserdruckleitungsnetzes während Niederschlags ermittelt werden mit dem Ziel, eine flexible, variable Beschickung der Kläranlagen zu ermöglichen. Stellgrößen für die Optimierung sind die Volumenströme oder Druckdifferenzen in den Pumpwerken und an den Schiebern im Abwasserdruckleitungsnetz. Dieser Abschlussbericht beschreibt detailliert die am Konrad-Zuse-Zentrum Berlin und am Institut für Angewandte Mathematik der Leibniz Universität Hannover durchgeführten Arbeiten. Er lässt sich gliedern in folgende Abschnitte: (i) Gesamtüberblick des Berliner Abwassersystems, Aufgabenstellung und Beschreibung der abwassertechnischen Anlagen, Daten für das Optimierungsmodell. (ii) Mathematische Modellierung des Gesamtsystems und der Komponenten, ggf. alternative Modellierungsmöglichkeiten, Beurteilung der Modelleigenschaften. (iii) Mathematische Ansätze und Lösungsmethoden mit Beurteilung ihrer Vorteile, Nachteile und Schwierigkeiten, Zusammenfassung. Während der Datenerhebung stellte sich heraus, dass das Abwassersystem hinsichtlich der Modellierung und Lösung in GAMS wesentlich komplexer ist, als es zunächst absehbar war. Dies betrifft insbesondere die Kanalnetze: hier verursachen Sonderbauwerke, wie Drosseln, Wehre und Heber zustandsabhängige Unstetigkeiten, die sich in GAMS nur mittels ganzzahliger Optimierungsvariablen adäquat modellieren lassen. Dadurch entsteht ein gemischt-ganzzahliges nichtlineares Optimierungsmodell (MINLP für engl. mixed-integer non-linear program) sehr hoher Dimension, das mathematisch wie rechentechnisch extrem schwierig zu lösen ist. So konnte bisher keine optimale Bewirtschaftungsstrategie ermittelt werden. Auch die Größe des Modells stellt eine Herausforderung dar: in der aktuellen Formulierung existieren in etwa 3 Millionen Optimierungsvariablen (davon gut 200.000 ganzzahlige) und etwa eine Million Beschränkungen (plus einfache Schranken). Somit ist das Modell etwa um einen Faktor hundert größer als bisher erfolgreich gelöste MINLPModelle. Es wurde versucht, das Abwassermodell mit dem MINLP-Löser Bonmin in Kombination mit dem NLP-Löser Ipopt in GAMS zu lösen (NLP für engl. non-linear program), erwartungsgemäß allerdings bisher erfolglos. Als Fazit bleibt festzuhalten, dass das im Rahmen dieser Studie erstellte Abwassermodell mit Standard-Optimierungstools derzeit nicht lösbar ist. Die angestrebten Untersuchungen erfordern zunächst weitere Forschungsarbeit, um das Modell einer numerischen Behandlung zugänglich zu machen. Außerdem wird eine weitergehende Vereinfachung der Beschreibung der Kanalnetzbausteine im Modell diskutiert.

Membrane processes stand as a promising technology to ensure a safe water supply at the community and the household levels. As the price of membranes has notably decreased over the last years, the market of membrane-based systems for decentralised applications has developed and diversified. In order to have a view of what the current market offers, 204 water companies were contacted and asked to characterise their Point-of-use (POU) or small-scale membrane systems, with a focus set on operation and maintenance, costs and energy requirements. Such study was not performed previously. With a 15% reply rate, the survey enables to identify the different market niches. That includes ceramic POU, organic POU, organic point-of-entries (POE), modular treatment units and emergency systems, whose technical characterization is further detailed in the Annex. Besides, the review of the marketed membrane modules reveals that ultrafiltration is the most available process. The survey also shows that the pre-treatment is a key parameter when considering options for decentralised water supply. As needs for sustainable solutions for small water supply are established, the membrane market is expected to grow and more standardised products to appear. The market evaluation can be summarized in Figure 1. Depending on the product niche, the membrane material and the filtration type, different degrees toward the market maturity are then highlighted. Such systems would be broadly applied in developed countries, but they represent also great potential for transition and developing countries. However, few systems designed for long-term operation with low-energy and low-chemical requirements exist yet. Therefore, the R&D identified within Techneau matches a non-fulfilled yet requirement.

The present study “Literature review on impact-based guidelines for stormwater treatment” provides an overview of international guidelines, which evaluate acute impacts of combined sewer overflows (CSO) on receiving surface water bodies. The overview should serve as a basis for the assessment of measured and simulated CSO impacts on Berlin surface waters within the projects “Monitor-1” and “SAM-CSO”, which are currently carried out at the Berlin Centre of Competence for Water. In contrast to the classical approach of sewer emission thresholds, impact-based guidelines focus on possible effects of CSO in the receiving surface water. Impact-based guidelines aim at deriving locally adapted measures to minimize CSO impacts to surface waters. Thanks to this local approach, potential protection measures can be planned dependent on the state of a specific river, reservoir or lake. The following study focuses on acute CSOimpacts, which were identified as relevant for the biocenosis of the River Spree in Berlin within the KWB project ISM: (i) Increased levels of unionised ammonium (NH3) through ammonium input. (ii) Low levels of dissolved oxygen (DO) through the input of degradable organic components, which lead to DO consumption. Guidelines from Germany, Austria, Switzerland, United Kingdom, France and USA are considered along with the approach by Lammersen, which assembles a number of scientific publications. The Austrian guideline (ÖWAV-RB 19) stops at distinguishing whether further investigations are necessary. In the US “CSO control policy” further analysis is delegated mostly to local institutions. The French “Arrêté du 22 juin 2007” also asks to take into consideration the local situation of the receiving water but does not give any limit values. The remaining four approaches provide a detailed evaluation scheme for critical NH3 and DO conditions, using duration-frequency-relationships. These relationships assume that pollution events of a specific duration may only occur in defined recurrence intervals (e.g. Figure 4.1). The Swiss guideline (STORM) is not suitable for dammed lowland river systems such as the Berlin River Spree, since it focuses on fast flowing rivers with salmonid fish populations. As a result there remain three approaches, which are interesting for the Berlin situation: the UPM guideline from the UK, the BWK-M7 guideline from Germany and the Lammersen-approach, which summarizes various scientific results. Apart from the dependency of critical concentrations on event duration and recurrence frequency, influence of temperature, pH and concurrent NH3-concentrations or DO-minima are considered by UPM and the Lammersen-approach. The relationships used by the three approaches for NH3 and DO are similar (see Figures 4.1, 4.3 and 4.4). Nevertheless, their comparability is limited, as the approaches generalize various local situations and cannot be derived strictly scientifically. As a first step we therefore recommend applying the three approaches to existing data from the River Spree and count the respective numbers of critical events. Based on the results it is possible to assess to which extent each approach is applicable for the situation in Berlin. As a second step experts need to evaluate the resulting critical events to distinguish suboptimal from lethal situations. For instance, the Lammersen-approach judges both (i) a two-day period with DO < 5 mg L-1 and (ii) a 30-minutes event with DO < 1.5 mg L-1 as critical. However in the Berlin River Spree (i) occurs basically continuously throughout the summer season and is tolerated by local fish species, whereas (ii) would probably lead to a major fish kill. As a consequence the prevention of (ii) should be given first priority. Based on the experience gained from the assessment of river monitoring data, simulation results can be evaluated in a third step. All the considered guidelines propose numerical simulation of sewer and receiving surface water systems. However only simple model approaches are discussed in detail, while specialized literature is suggested for complex cases. If numerical simulations are used for the planning of concrete measures, model uncertainties must be indicated to avoid feigning accuracy of results that cannot be provided. The Swiss STORM guideline suggests using Monte-Carlo simulations to calculate probabilities of the recurrence of critical events for possible management measures. We suggest a similar approach for the Berlin situation. Thus, decision makers could weigh cost against probability of success for proposed measures.

The use of groundwater for public water supply and irrigation has many benefits for water suppliers as well as for consumers. Over the last decades availability and consumption of this valuable resource has increased worldwide along with technical progress, but it has often been ignored that any abstraction of groundwater is an intervention in the balance of the natural water cycle. Managed aquifer recharge (MAR) present the double interest : 1. to be a possible technical answer to over-exploitation of groundwater reservoirs and can contribute to water resource preservation and possibly reuse 2. to provide a natural cleaning step to pre-treat surface water for drinking water supply, and therefore could contribute to reduce the need for highly sophisticated treatment methods which are cost intensive in installation and also in maintenance. In many parts of the world, such as low income countries, MAR offers the possibility to profit from the storage and purification capacity of natural soil/rock and to guarantee a sustainable management of groundwater. River bank filtration is an ancient and widely used method that currently provides water to a large number of population in EU (45% of Hungarian water supply, 16% of German water supply, 5% of The Netherland water supply). River bank filtration relies on natural conditions to operate efficiently and allow to produce a quality of water which, in some cases, doesn't required further treatment before distribution (such as in Berlin). There are now many evidences that global environmental conditions are progressively changing and may impact existing water supply scheme by bank filtration. The extensive study of bank filtration systems in different environmental settings (such as in India with higher temperature, different surface water quality, systems subject to monsoons and flooding ...) will allow apprehending the limitation that current bank filtration systems may face, and highlight the possible need for adaptive strategies. The aim of this report is to document work performed within the first 6 months since the start of WP 5.2 of TECHNEAU integrated project and to give an overview of the results and future planning. This includes detailed regional investigations, field studies and laboratory work performed in collaboration between the KompetenzZentrum Wasser Berlin gGmbH (KWB), the Indian Institute of Technology in Delhi (IIT) and the Freie Universität Berlin (FUB). Preliminary studies at potential sites in different parts of the world were performed prior to the TECHNEAU Project with the aim to investigate their suitability for RBF and thus to allow for deeper investigation within TECHNEAU. These preliminary studies were carried out in the cities Kaliningrad (Russia), Recife (Brazil) and New Dehli (India), and were funded by Veolia Water. In Recife (Brazil), the investigation performed by the FUB showed that both hydrogelogical data and model results indicate that the area is not suitable for the production of drinking water by RBF in sufficient amounts due an unfavorable hydrogeological conditions (too low transmissivity of the target aquifer because of the low content of sand in the samples and the scarce distribution of sandy sediments). At this point further investigations were stopped since no alternative field site area was found. In Kalingrad, water quality data that was gained in the preliminary study from the field site and will be compared with the data gained from investigations in Delhi and Berlin. In Delhi, India, the appropriate conditions, as well as the establishment of a valuable collaboration with the IIT, has lead to the implementation of three different field sites (in three different conditions). The activity performed within the techneau framework and included (i) the integration of existing information and literature on local climate, geology and water supply system, (ii) the detailed investigation about the local hydrogeology and ground and surface water quality and (iii) the development of a GIS (Geo Information System). In agreement with local authorities, three different field sites were selected in the territory of Delhi, representing distinctly different environmental conditions within the district. According to local conditions, a net of 17 groundwater observation points (piezometers) has been designed and installed on each of the field sites. A description of local geology, including stratigraphical charts has been elaborated, based on the evaluation of information obtained during the drilling and from analysis of sediment samples. A strategy for monitoring of water level and water sampling analysis has been developed, and monthly field campaigns have been carried out. Water samples have been analyzed, considering a broad variety of parameters including major chemical contents, trace substances and pathogens. Hydraulic tests have been conducted to obtain aquifer properties in order to estimate travel velocities during underground passage.

The term "Watergy" was coined by the Alliance to Save Energy to describe the strong link between water and energy in municipal water systems. The Watergy approach helps cities realize significant energy, water and monetary savings through technical and managerial improvements in water supply and wastewater treatment systems, creating efficiencies that provide consumers with quality service with a minimum of water and energy. Efficiency in the water sector involves both the end use of water - such as efficient toilets, low-flow showerheads and reducing peak demand - as well as efficiencies in the supply of water. This paper focuses on the water supply system itself since in many cities most of the inefficiencies occur before the water even reaches the end user. Watergy principles have been applied in numerous cities around the world, demonstrating that water efficiency measures repay themselves quickly and yield many rewards: improvements in water service, immediate increased water delivery, reduced water and energy consumption, and more revenue for system upgrades and new customer connections. Opportunities abound throughout all stages of a water supply system. The most promising areas for intervention within water supply systems are: (i) improving the pumping system, (i) managing leaks, (iii) automating system operations, and (iv) regular monitoring (preferably with rigorous metering of end use). These improvements often pay for themselves in months, most do so within a year, and almost all recover their costs within three years. The pumping system is all important, since every liter of water that passes through the system represents a significant energy cost, a cost that is magnified by every liter lost to leaks. Pumping improvements range from lower cost measures like soft starters for motors, trimming impellers (when pumps are over-sized) and re-winding motors, to higher cost measures like replacing inefficient pumps with efficient ones and installing variable speed drives. System automation saves water, energy and operation costs, improves service, and lengthens equipment life. Automation handles operational functions in real time in response to changing situations. Examples are optimizing pressure in the network, triggering alarms in case of emergency, and turning off pumps. Regular monitoring of the system components, operations, and performance is essential targets. in order to track performance and evaluate it against a set of benchmarks and Incorporated as part of the larger O&M protocol, monitoring is a no- or low-cost efficiency enhancement within reach of all utility budgets. Effective management of leaks can save enormous quantities of water and energy. Leakage rates can be lowered dramatically with automated controls that reduce pressure in the network, especially at night. Pressure management is generally more cost-effective than expensive repairs to numerous leaks in buried pipes. This paper provides a comprehensive overview—suitable to all technical levels—to introduce the reader to the approaches and benefits of Watergy. It is intended for a wide audience ranging from municipal and water utility decision makers, to funding organizations, to technical utility staff who want a solid understanding of what a water efficiency program entails without a high level of technical detail.

Urban water courses are considerably degraded in terms of their hydrology, riparian and channel morphology, substrate heterogeneity and habitat features as well as water and sediment quality. In addition, the combined sewer overflows and the ecotoxicological impacts of its components lead to a change of the physical-chemical and microbial mass balance affecting the biocenoses of higher trophic levels. Combined sewer overflows are therefore an additional stress to the ecological status of the urban course of the River Spree and of its channels, which is damaged already by both preload and background load of the aquatic environment. With regard to the assessment of the ecological water status, the European Water Framework Directives gives priority to the aquatic biocenoses in their capacity as ecological quality parameters. Against this background, an immission-oriented approach for the assessment of combined sewer overflows has to describe also their impacts on the biocenoses of the macrozoobenthos, the fish fauna, the macrophytes and the phytoplancton. These biocenoses are protected against the harmful impacts resulting from CSO only if the modification of their physical and chemical environment is avoided or reduced to an ecologically tolerable level respectively. In case that unfavourable impacts cannot be completely eliminated, the degree of impairment and the number of damaging CSO discharge events, which appear to be acceptable, should be defined. The present study is based on the bibliographic study „ Impact of urban use on the mass balance and the biocoenosis of lowland rivers under special consideration of combined sewer overflows” and deals with the assessment of CSO impacts on the ecological situation of the urban Spree and the channels (Cyprinid water bodies). In general, the immissionoriented assessment of CSO impact on the biocenoses (macrozoobenthos, fish fauna) requires the observation of the intensity, duration and frequency of occurrence of the individual events based on the assumption that, due to the background pollution, top priority is currently given to the acute CSO impacts. Requirements for the protection of aquatic biocenoses are developed with regard to the target parameters oxygen and ammonium/ammoniac and ecological tolerances of the biocenotic subjects of protection, which are strongest influenced by CSO. Initially, it is discussed to what extent the already existing results from laboratory investigations can be transferred to field situations. Next to the commonly accepted threshold values for oxygen concentrations during continuous persistent loads, particular requirements for the oxygen balance in case of peak loads are formulated.

The recycling of plant-nutrients as nitrogen, potassium and phosphorus from human nutrition is considered to be a preposition towards sustainable agriculture. Commonly, human excreta are collected together with waste water and other liquid wastes from households and small industries. During the treatment in central sewage-works the valuable nutrients cannot be separated from potentially harmful substances such as heavy metals. Therefore, the application of sewage-sludge on agricultural fields is strongly limited. Today, in Germany a major amount of sewage sludge is burned in waste incineration plants. This means a dissemination of phosphorus, potassium and nitrogen into the atmosphere. Phosphorus and potassium fertilisers are extracted in mines and as such non-renewable. A shortage of phosphorus to be used as fertiliser is expected to arise within the next 80 years (STEEN, 1998). Alternative Sanitation Concepts such as the separate collection and treatment of urine and faeces prevent the contamination of the plant nutrients with potentially harmful or unwanted substances from other liquid wastes. The main feature of this concept is the use of a separation toilet. It can be used in the same way as any other common flushing-toilet but has a special valve for separate urine collection. The urine can easily be stored in containers e.g. in the basement of a house and used as fertiliser. A composting process ensures hygienisation of the solid faeces separated from flushing water. Due to its low content of nitrogen all remaining waste water can be treated in a constructed wetland. The studies introduced followingly were carried out within the scope of the SCST (Sanitation System of Separate Treatment) research project. This EU-Life demonstration project is a result of the cooperation of the KompetenzZentrum Wasser Berlin, Berliner Wasserbetriebe, Veolia Water and Anjou Recherche. It contains a setup of a complete Alternative Sanitation system including the conversion of 10 private households and two office-buildings as well as a biogasplant and a constructed wetland in Berlin-Stahnsdorf. It was the aim of the SCST-project to demonstrate the feasibility of an alternative sanitation system working with separation toilets. Apart from the technical questions to be answered it was necessary to know how urine and faeces are to be used in agriculture. The following four questions point out the aspects which needed to be investigated in detail: (i) How are the fertilising effects of urine und faeces compared to conventional mineral fertiliser? (ii) What impact has urine to soil organisms? (iii) How much gaseous nitrogen is lost after application? (iv) Would farmers and consumers accept urine as fertiliser? In this report you will find the four mentioned aspects investigated. This was done by carrying out laboratory or field experiments as well as acceptance SCST Final Report Task 8 – Fertiliser usage – Muskolus, Humboldt University of Berlin - 4 - studies for each of them accordingly. You will find a detailed description of the methods and materials used as well as the results and statistical evaluation as appropriate. Regardless of the advantages possibly reached by a treatment of urine in the presented studies it was assumed that pure urine was used. It is still not known what kind of processing is suitable to reduce the water content of urine or any unwanted substances and whether the energy input during the treatment is justifiable or not. However, some results of the studies followingly presented may change if treated urine instead of pure urine was used.

The objective of the studies performed in the scope of the Integrated Sewage Management (ISM) project on combined sewer overflows in Berlin, Germany was to develop methods that would make it possible to assess wastewater management measures performed under the city’s water management permit as well as more sophisticated strategies (e.g., global real time control) through the application of water body-related criteria. For this purpose, a preliminary study was first performed to characterize the underlying water body-specific processes and hydraulic, physical, chemical and ecological parameters relevant to the status of Berlin’s surface waters (LESZINSKI et al., 2007a). The second step involved the development of a method for water quality-oriented assessment of wastewater management measures (LESZINSKI ET AL., 2007b). In addition to the already recognized thresholds for dissolved oxygen concentration during continuous, long-term water load conditions, particular focus was placed on formulating requirements for oxygen demand under peak load conditions. Ammonia toxicity due to sewage input, another important stress factor for aquatic ecosystems, was also analyzed and threshold values for both chronic and acute peak ammonia loads were defined. The results of the third phase of this research are described in this report. Two numerical simulation models (for urban drainage networks and surface waters) were combined and the feasibility of the developed method was evaluated based on the case of a combined sewer overflow event documented by the surface water monitoring. The simulations were performed using InfoWorksTM CS hydrological/hydrodynamic urban drainage network modeling software (ISM model) and the GERRIS/HYDRAX/Qsim unsteady ecosystem modeling system. The latter model was developed by the Federal Institute of Hydrology in Koblenz and is used by the Senate Department of Health, Environment and Consumer Protection (SenGesUmV). The present report describes the theoretical principles of the utilized models, the base of data available for analysis of the selected event, and the assumptions made in cases of missing input data for hydraulic modeling as well as for the water quality simulations. The one-dimensional hydraulic modeling results for the branched surface water system of the reach Berlin-Charlottenburg demonstrated that the hydraulic conditions can be simulated with satisfactory accuracy using the current data. In the case of water temperature, it was also possible to achieve a high degree of agreement between the measured and computed values in spite of the lack of highresolution temporal input data from the tributaries (Landwehr Canal, Panke River, BerlinSpandau Ship Canal). However, this was not the case for dissolved oxygen concentration, the main parameter used for evaluation of combined water treatment. The DOC simulations computed using input data based on a monthly sampling interval did not show satisfactory agreement with the online measurements in the water system. Dry-weather biological processes, which were associated with high-level, short-term oxygen enrichment or consumption, could not be depicted in the simulations. After completion of the water quality simulations, the effect of variation of individual input parameters was assessed. This analysis showed that no significant improvement of agreement with the measured values could be achieved by adjusting the assumptions for individual parameters (chlorophyll-a and BSB5). In the case of ammonia, the second most important parameter, the available sampling data from the tributaries in the investigated water system were collected only once a month, if at all. Therefore, it cannot be expected that the temporal distribution of this parameter was correctly reflected by the model. The number of validation measurements taken within the water system was also insufficient. Summarizing the results of the study of the linked urban drainage/surface water quality model, which was tested for the first time, it can be concluded that InfoWorks CS and GERRIS/HYRDRAX/Qsim provide problem-oriented simulation tools for reaching the objective of ISM study of assessing various scenarios for reduction of impacts from combined sewer overflows. By contrast, the available data are deficient and do not allow to adjust and calibrate the models to meet the specific needs of this task, particularly in light of the fact that short-term effects of combined sewer overflows are to be analyzed.