The goal of this study is to analyze whether the integration of a Hydrothermal Carbonization (HTC) process into sewage sludge disposal routes improves the holistic energy balance compared to state of the art technologies. Furthermore the decisive parameters for the improvement are identi ed. For this a static model is set up within the energy and material flow calculation software Umberto. Within the selected treatment scenarios without and with anaerobic digestion the Cumulative Energy Demand (CED) and Global Warming Potential (GWP) are determined per functional unit disposal of one kg TSsludge. The model is fed with full-scale data from state of the art sludge treatment and data of a pilot HTC plant. It comprises all relevant processes including their chemicals and energy demands as well as transportation of materials. Expenditures for infrastructure are excluded. The reference input flow is based on the annual sludge amount of a waste water treatment plant for 500,000 people equivalents. The final disposal options of the sludge or hydrochar are either co-incineration within a lignite power plant or mono-incineration. Some co-products such as electricity, biomass fuel (dried sludge, hydrochar) and nitrogen fertilizer are created during sludge treatment and accounted for as substitutes for production of equivalent resources. HTC distinguishes from the conventional sludge treatment by improved mechanical dewaterability of the products. It reaches dry matter contents of ~ 65%. Trade-offs are the significant process heat demand of 88kWh/m3 sludge at high temperatures > 220 °C and a decreased mass yield of 72 % for the undigested and 75 % for the digested sludge. The dry matter loss results in process liquor with multiple load compared to raw sludge liquor (80 x org. C, 60 x Ntot, 25 x Ptot). The CED and GWP results generally show good correlation. For the CED of raw sludges the net values range from savings of -11.7 to expenditures of +1.8MJ/kg TS. The GWP ranges from -1.07 to +0.43 kg CO2-eq/kg TS. The net values for the HTC scenarios exceed the reference scenarios for undigested sludge when the dry matter content after sludge dewatering is < 27% or if it is ~ 27% and the process heat demand of the HTC can be reduced by half e.g. via insulation. However, the best scenario for undigested sludge includes HTC with a small scale digester only for the liquor. The loads are largely reduced, saving energy for the return ow treatment and producing biogas for use in a CHP plant. The heat can be fed to the HTC reactor while grid electricity is substituted. In disposal routes including sludge digestion the CED ranges from -11 to -1.1MJ/kg TS and the GWP ranges from -0.73 to +0.22 kg CO2-eq/kg TS. The scenarios with HTC exceed the reference scenarios irregardless of the TS after dewatering. The HTC liquor is returned to the digester, reducing the load and yielding extra biogas as mentioned above. Also, with sludge digestion the HTC process benefits from the larger amount of CHP heat. It is sufficient to cover the heat demand within the analyzed scenarios. The reference sludge treatment is based on representative full-scale data, but the pilot plant data of HTC showed inconsistencies. The data has to be validated in full scale. Furthermore, important aspects such as refractory COD within the hydrochar liquor, pollutants such as heavy metals, legal aspects of the hydrochar incineration, nutrient recovery and economic aspects have to be addressed in future studies.

Objective of this synthesis report is to summarize the main achievements of the WELLMA-2 project. Based on the preparatory phase WELLMA-1 (2007-2009), the main project phase WELLMA-2 (2009-2012) included extensive laboratory, pilot-scale and field site investigations aiming at optimizing the operation and maintenance of drinking water production wells with respect to costs, energy efficiency and sustainability. The main reason for inefficient well performance is so-called well ageing. Deposit formation due to multiply correlated biological, chemical and/ or physical clogging processes in and around the well cause a decrease in performance. Thus, the interdisciplinary WELLMA-project team aimed at improving the efficiency of drinking water production wells by providing a scientific basis to support operators in their efforts to reduce well ageing. This included the development of guidance and recommendations for an adapted and well-planned operation scheme and maintenance strategy to sustain or reinstall the well performance. Well ageing processes were intensively studied at a multitude of vertical drinking water production wells located in Berlin, Germany and near Bordeaux, France. Thereby, classical monitoring and diagnosis methods, such as pumping tests and TV inspections, but also newly developed own experimental setups, such as the in-situ measurement of oxygen, depth-oriented water sampling or the exposure of object slides and bio-reactors for biofilm growth were applied. This synthesis report follows the project outline featuring four work packages dealing with (i) the identification of ageing types and the site-specific ageing potential from optimal data processing of site and well characteristics to provide decision support for the diagnosis and subsequent optimisation of well operation, monitoring and maintenance, (ii) field methods and experimental setups applied within the WELLMA-project to investigate mixing processes, oxygen uptake and biofilm formation, (iii) the impacts of intermittent operation on the uptake potential and distribution patterns of oxygen, and (iv) the efficiency of hydrogen peroxide treatments for preventive well maintenance against biochemically induced iron ochre formation and the oxygen uptake potential correlated to the decomposition of H2O2. Intermediate data were presented at various occasions at scientific and practiceoriented conferences, e.g. the Association for General and Applied Microbiology (VAAM), the International Water Association (IWA) Groundwater conference, International Association of Hydrogeologists (IAH), Berlin-Brandenburger Brunnentage, Wasser Berlin etc. and in related papers. A publication list is given at the end of this synthesis report.

Recent infrastructure studies underline the general deterioration of sewer system and the risk reversing public health, environment and increasing costs (ASCE, 2009). Since the origin of sewer systems in the 19th century, sewers have been installed at different periods using available standards and technologies. Sewer assets have limited service life and it is crucial to assess their condition throughout their life cycles to avoid potential catastrophic failure and expensive emergency rehabilitation due to their deterioration (Hao et al., 2011). This report first presents the wide panel of inspection technologies available to obtain information about sewer defects and condition. Visual inspection (e.g. Closed-circuit television CCTV, zoom camera) appears to be the industry standard for sewer inspection. It provides visual data (images and/or videos) of the internal surface of the pipe. Defects are usually coded manually by the inspection staff according to standard coding methods. In Europe, the current codification system is the normative EN 13508-2 for visual inspection (EN 13508-2, 2011) used by the CEN-Members (European Committee for Standardization). In addition, physical techniques are available that can give further information and details about pipe defects. These techniques do not replace the CCTV inspection but can give deeper insights on the type and severity of defects. Sonar and Lasers enables to analyze pipe geometry and can identify defects such as deflections, cracks, sediments or corrosion. Ultrasonic testing and magnetic flux leakage (MFL) are applied directly on the pipe wall. They enable to measure wall thickness and detect pipe defects such as corrosion, deflections and cracks. Ground Penetrating Radar (GPR) and Infrared Thermography are used from above ground and are useful to locate pipes and identify bedding conditions, voids and leaks. Finally, network wide inspection technologies like smoke testing or Distributed Temperature Sensing (DTS) can locate cross-connections and/or sewer infiltration. The purpose, inspection procedure and limitations of these methodologies are briefly presented. On a second step, this report presents the available classification methodologies developed to interpret automatically visual CCTV inspection reports and evaluate sewer condition. These methodologies enable to transfer the extensive amount of visual inspection data from CCTV inspection into a more easily manageable number, useful to support asset management practices. Most approaches have a similar goal: they aim to rank rehabilitation priorities and support municipalities in the definition of rehabilitation programs. They do not pretend to replace the knowledge and analysis skills of a local expert but can help him to identify rehabilitation priorities. All methodologies provide an overall condition score for each sewer segment or sub-scores for different requirements (e.g. structural and operational condition) or dysfunctions. From the review of available methodologies, two main approaches can be distinguished: priority based and substance based methodologies. For priority based methodologies, the calculation of sewer condition grades is based on the most severe defects, the density of defects and/or the defects length. Condition grades express the priority of rehabilitation, i.e. the emergency of action regarding the probability of failure or collapse. For substance based methodologies, the final score is calculated based on the length of sewer that will be affected by rehabilitation actions. Substance based methodologies do not aim to assess the condition of sewers but rather to rank sewer pipes considering the amount and type of rehabilitation needs: replacement, renovation and repair. Each methodology aggregates and combines sewer defects in a very different way making very hazardous the benchmarking of final scores from different methods. Therefore, municipalities using different evaluation system are not able to benchmark the condition of theirs networks. Finally, the accuracy of the classification results remains a key issue, crucial for the further use of inspection data to support asset management strategies.

The adoption of decision support tools for the definition of cost-effective strategies is seen to gain more importance in the coming years. This development is due for one part to the general degradation of the existing systems and for the other part to changes into the regulations and demands for more transparency in decision-making (Ana and Bauwens, 2007). A key element of decision support systems is the ability to assess and predict the remaining life of the assets (Marlow et al., 2009). For this purpose, deterioration models have been developed to understand and describe the sewer aging based on available CCTV inspections and a list of factors that influence the deterioration. This report first describes the potential sewer deterioration factors and analyzes a panel of literature case studies regarding the relevance of each factor on sewer deterioration. Results are hardly directly comparable, because of the different construction practices, historical backgrounds and environmental conditions of the networks investigated. However, some trends regarding the most significant factors may be identified. In most studies, the construction year and the material seem to be the most relevant factor to explain sewer aging. Pipe size, depth, location and sewer function show generally a medium significance on sewer deterioration. Pipe slope was found to have a low significance for the structural deterioration, but a high relevance on the hydraulic deterioration. The effect of other factors as pipe shape, pipe length, soil type, sewer bedding, presence of trees, installation method, standard of workmanship, joint type, and ground water level have been highlighted but rarely or never investigated. On a second step, this report presents three main approaches for sewer deterioration modeling: deterministic, statistical and artificial intelligence based models. The models can be further categorized into pipe group and pipe level models (Ana and Bauwens, 2010). Pipe group models (e.g. Cohort survival or Markov) can be used to predict the condition of a group of sewers or cohorts and are useful to support strategic asset management, i.e. the definition of long term strategies and budget requirements. These models enable to evaluate the efficiency of several scenarios at the network scale. Pipe level models (e.g. regression, discriminant analysis, neural networks) can be used to simulate the condition of each single pipe. They may be useful to set priorities and justify asset management operations. Pipe level models are tools that can support the utilities in the short and mid-term planning and determine at a finer resolution how, when, and where to rehabilitate sewers. Literature results indicate that cohort survival and Markov models are two useful approaches for modeling the degradation of pipe groups. However, the quality of prediction of these models depends highly on the availability of a large amount of inspection data. Extensive datasets are required to create representative sewer groups (cohorts) with sufficient inspected sewers in each condition state. Regression and Discriminant Analysis were tested on several case studies but showed pretty low prediction performances. Three main reasons could be (i) the non-validity of model assumptions, (ii) the biased distribution of the datasets in terms of number of samples for each condition state and (iii) the lack of data for important deterioration factors. Neural networks have proven to be successful tools for the prediction of the deterioration of individual pipes. However, they require (i) relatively complex and time-consuming training processes and (ii) extensive datasets of CCTV inspection and deterioration factors. Only very few case studies intended to evaluate the quality of prediction of these deterioration models. Furthermore, validation results are often contradictory and hardly comparable since (i) the data available for model calibration differ (percentage of CCTV available, type of deterioration factors available) and (ii) the metrics of the methodologies used to assess the quality of prediction differ. Thus, there is still no clear conclusion about the best modeling approach depending on the modeling purpose (pipe group or pipe level). There is also no clear conclusion regarding the quality of prediction that can be reached since in most case studies only a few percentages of CCTV data were available and many data regarding potential deterioration factors were missing. Further research work is needed in order to (i) identify the most appropriate modeling approach depending on the modeling purpose, (ii) understand the influence of CCTV data availability on the modeling results, (iii) analyze the influence of input data uncertainty (CCTV and deterioration factors) on the modeling processes and (iv) find out the optimum input data requirement (availability of CCTV data and deterioration factors) for model calibration.

Abwassereinigungsprozessen an. In Deutschland fallen jährlich etwa zwei Millionen Tonnen Klärschlammtrockensubstanz aus kommunalen Kläranlagen an. Der Anteil von thermisch entsorgten Klärschlämmen stieg von 31,5 % im Jahr 2004 auf über 55 % im Jahr 2011 an [Umweltbundesamt, DESTATIS 2012]. Eine ökologisch nachhaltige und ökonomische Klarschlämm-Entsorgung wird seit Jahren unter rechtlichen, politischen und technischen Aspekten in Deutschland diskutiert. Die Schlammbehandlung und Entsorgung ist immer noch einer der größten Kostenfaktoren in kommunalen Kläranlagen. Insbesondere die Schlammentwässerung mit Zentrifugen hat einen maßgeblichen Einfluss auf die Betriebskosten. Die Entsorgungsverfahren werden unter Berücksichtigung von Quantität und Qualität des Schlamms und in Hinblick auf die gewünschten Entsorgungsziele kombiniert. Dabei können folgende Verfahrensstufen genutzt werden: Stabilisieren, Eindicken, Konditionieren, Hygienisieren, Entwässern und Trocknen. Die anzuwendenden Verfahren werden entsprechend ausgewählt und in unterschiedlicher Reihenfolge durchgeführt. Die Voraussetzung für die jeweils angestrebte Verwertung oder Entsorgung des Schlammes ist die weitgehende Abtrennung des Wassers von den Schlammfeststoffen. Heutzutage ist eine Kombination mit Eindickung, Konditionierung, maschineller Schlammentwässerung (ggf. Trocknung) besonders von Bedeutung. Die Konditionierung ist dabei eine technisch und wirtschaftlich wichtige Vorstufe zur Schlammentwässerung. Ziel dieser Masterarbeit ist eine Optimierung der Konditionierung und Entwässerung von Klärschlamm unter Einsatz von unterschiedlichen Konditionierungsmitteln mit besonderem Augenmerk auf den Polymerbedarf. Im Rahmen des „Decamax“ Projekts des Kompetenzzentrums Wasser Berlin (KWB) wurde die Schlammentwässerung im Labormaßstab untersucht. Es sollten verschiedene Möglichkeiten der Betriebsoptimierung in der Schlammentwässerung in Theorie und Praxis systematisch verglichen und bewertet werden. Im Fokus der Untersuchungen stand die Zentrifugation mit ihren vorgeschalteten Prozessen wie Schlammvorerwärmung mit Überschusswärme, Flockenbildung vor der Entwässerung und andere Parameter. Im Klärwerk Waßmannsdorf wird seit Anfang der 90-iger Jahre die Phosphateliminierung im Abwasserbereich auf biologische Art vorgenommen. Bei der Schlammbehandlung in Waßmannsdorf wird eine gezielte MAP-Fällung in einem speziellen Reaktionsbehälternach der Faulung und vor der Faulschlammentwässerung betrieben. Durch das Ausgasen von CO2 steigt der pH-Wert deutlich an und dadurch fällt Magnesiumammoniumphosphat (MAP) kristallin aus. Die gezielte Fällung von MAP begünstigt eine bessere Entfernung der freien Orthophosphationen aus dem Schlamm und gleichzeitig führt sie auch zu einer Absenkung des Polymerbedarfes und bessere Entwässerungsgrad. Ziel dieser Masterarbeit ist die Optimierung der Schlammentwässerung in Waßmannsdorf durch Zugabe von chemischen Konditionierungsmitteln wie z. B. Eisen- und Aluminiumsalze sowie Kalk, um eine bessere Entwässerbarkeit zu erreichen. Als Vorbereitungsstufe wurden die Untersuchungen mit den Schlämmen aus der Kläranlage Stahnsdorf durchgeführt. Weiterhin sollte der optimale Polymerbedarf und die Scherstabilität der konditionierten Flocke unter verschiedenen pH-Bedingungen bestimmet werden.

The overall goal of the project Cosma-1: “Geological CO2 storage and other emerging subsurface activities” is the assessment of potential impacts of subsurface activities on shallow aquifers used for drinking water production. The first two deliverables (D 1.1 and D 1.2) dealt with general approaches for risk assessment and a description of potential hazards and hazardous events, which might be a risk for shallow freshwater aquifers, as well as lessons learned from existing geothermal energy production and storage sites in Germany. This Technical Report describes the activities of the second phase of the project COSMA-1 and focuses on the compilation of geological and hydrogeological background data (average values) and the development of a simplified conceptual hydrogeological model for a setting typical for the Northern German Sedimentary Basin. The hydrogeological model of the Cenozoic includes Quaternary and Tertiary aquifers down to the layer beneath the Rupelian clay. On this basis, a numerical model with the program Modflow (PMWIN 5.3) was implemented as no complex geometries had to be considered. The structural geological model of the target formation for underground utilisation, the Detfurth Formation (Middle Bunter), incorporates four different fault systems with nine faults in total enclosing the area of interest. Further, a concept for modeling the interaction between deep, consolidated, saline aquifers with unconsolidated freshwater aquifers in a setting typical for the Northern German Sedimentary Basin was developed. This included the model selection, model parameterization, definition of boundary conditions and implementation in hydrogeological flow model software packages. In the further course of the project, a scenario analysis will be performed by using the numerical hydraulic model of the Middle Bunter and the simplified numerical groundwater model of the Cenozoic. The numerical models will be used to assess the key parameters, having an impact on the upconing of deeper saline groundwater beneath the well fields of water works (in shallow aquifer) due to imposed pressure signals.

Im BMBF-Forschungsverbund „Risikomanagement von neuen Schadstoffen und Krankheitserregern im Wasserkreislauf (RiSKWa)“ wurde die Definition von „Indikatorsubstanzen“ als ein interessantes Querschnittsthema identifiziert. Es wurde dazu eine Arbeitsgruppe gebildet, die sich die Aufgabe stellte, einen Leitfaden zur Zweckbestimmung, Auswahl, Bedeutung und Interpretation von polaren organischen spurenstoffen als chemische Indikatoren zu verfassen. Mit Hilfe der Indikatoren sollten insbesondere anthropogene Veränderungen der Wasserqualität erkennbar sein, sowie natürliche Prozesse und technische Aufbereitungsverfahren überwacht und gesteuert werden können. Diese Indikatoren dienen nicht der Bewertung der Wasserqualität. Mögliche Anwender sind die Bearbeiter in den Verbundvorhaben des RiSKWa-Programms und in weiteren Vorhaben in den Bundesländern, die sich mit Spurenstoffen befassen, Fachbehörden, Forschungseinrichtungen, Wasserlabors der Trinkwasserversorgung und Abwasserreinigung und Ingenieurfirmen, die wassertechnologische Themen der Spurenstoffentfernung bearbeiten. Einen Überblick über mögliche Quellen, Eintragspfade und Barrieren im Wasserbereich zeigt die folgende Abbildung aus dem Bericht eines DECHEMA-Arbeitsausschusses „Pfad- und wirkungsspezifische Indikatorsysteme für Wasser- und Bodensysteme“ (Leitung: W. Dott). Dieser Leitfaden wird dabei sehr wesentliche Teile des dargestellten Systems behandeln.

This report aims at documenting the scientific evidence at 4 managed aquifer recharge (MAR) sites in India after 18 months duration of the EU (European Union) funded project SAPH PANI. The site investigations include compilation of previously existing data, a wide range of field experiments, surface-/groundwater and sediment sampling, data analysis, interpretation and the development of (preliminary) conceptual models. The MAR sites are realised under a wide range of geological and hydrological conditions and the covered aspects can be summarised as:…

Water is one of the sectors where climate change will be most pronounced. While the extents of the impacts are not known yet, it is the right period to prepare the utilities to adapt to the global changes in an urbanising world. Adaptation to climate change, though not always perceived as such, is often already reality in the urban water sector. Several adaptation strategies have been tested to address the key questions: Adapt to what? What to adapt? How to adapt? In this context, within the framework of the EU-project PREPARED, a tentative classification and catalogue of implemented initiatives in the water sector has been compiled. This catalogue is organised into four major categories of initiatives: (1) risk assessment and management, (2) supply-side measures, (3) demand-side measures and (4) global planning tools. The document aims at providing examples on how utilities could go ahead into preparing their water supply and sanitation systems to climate change. Initiatives include various measures ranging from the promotion of active learning to the prevention of sewer flooding and water conservation measures. Within PREPARED, this catalogue is supporting the development of solutions. Being a living document, it is updated regularly along the project when new solutions and initiatives are known. In addition, this work and the subsequent database of adaptation initiatives are accessible to a broader audience thanks to the web-based ‘WaterWiki’ of the International Water Association (IWA).