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.

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.

Last decades the concern about energy consumption has globally arisen due to awareness on climate change and the increase of energy prices. In the water field the nexus between water and energy has been extensively studied, however, there has been little discussion about energy-efficient specific approaches. This master thesis is part of the OPTIWELLS project which addresses to determine more energy efficient techniques for water supply operation, in particular for water abstraction well fields. One option to optimize a well field preserving its structure or components is the “smart well field management”, which maximize the time during which the pumps are performing on their best efficiency point, guaranteeing the water demand. The smart well field management is complex and accounts for various integrated processes. The aim of the project is to develop a prototype of a software tool able to cope with this complex optimisation problem. In particular, this master thesis deals with the modelling of a case study, applying methodologies that will be implemented in the OPTIWELLS prototype tool. Results and methods of data analysis for a well field, including a site audit, are described. The well field modelling was carried out with EPANET software by means of its Programmer’s Toolkit. No reliable data to validate the energy consumption estimation of the model were available. However, the report shows that observed hydraulic conditions of an abstraction well field can be accurately reproduced. The impact of different modelling approaches and amount of data available on energy evaluation is also drawn. Some insight into the well field current conditions (current pump curve, drawdown, water quality, specific energy demand,..) are discussed and recommendations or the operation of the case study site will be given.

Within the context of continuously increasing CO2 concentrations in the atmosphere, as well as diminishing reserves of fossil fuels, finding new ways for autarkic and “climate friendly” energy production becomes more and more important. The development of emerging subsurfaces activities like Carbone Capture and Storage, and Hydraulic Fracturation might offer new options to tackle all three of the mentioned challenges. But, carbon capture and storage (CCS) and unconventional gas exploration (“hydro-fracking”) have in common that they impact parts of the subsurface and may thus potentially have an effect on fresh water aquifers. The combination of all the most recent studies about GCS and Hydro-fracking, allows the identification of a broad panel of key parameters that can assess and indicate a groundwater contamination resulting from emerging subsurface activities. Strong emphasis needs to be put on the fact that numerous new monitoring, verification and accounting tools are being developed worldwide threw researches programs. However, actually, it seems that the most efficient monitoring and early warning network should be based on the combined used of the most suitable (site-specific) geophysics and geochemicals tools.

Today, groundwater is one of the most important fresh water resources in big cities of the world. On one hand, the population growth and urban development and on the other hand, climate change and decreasing precipitation will increase the vital role of underground water resources to supply water for the cities, therefore an increase in the energy consumption in well fields has to be expected. It is becoming more difficult to ignore the cost of pumping energy for water stakeholders in Germany and Europe. In recent years, there has been an increasing interest in optimisation of energy consumption in different fields. The goal of this study is first to design a relational database to store the information of submersible pumps and second to develop a database management system for this pump database. The pump database is intended to be used in prototype model software aiming at the minimisation of a well field's pump energy demand. To this end, two approaches of assessing the necessary data for submersible pumps, and building a relational database are going to be discussed in this study. Finally, two applications with graphical user interfaces which have been developed by using the programming language “R” are presented for loading the data into the database, visualizing the database tables and plotting the pump curves.

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.

Combined sewer overflows (CSO) after heavy rainfall can cause acute depletions of dissolved oxygen (DO) in the Berlin River Spree. A planning instrument for CSO impact assessment has been developed in the framework of the research project MIA-CSO at the Kompetenzzentrum Wasser Berlin. This instrument couples the sewer model InfoWorks CS, the water quality model Hydrax/QSim and an impact assessment tool. Within this thesis it is tested for various CSO management strategies and climate change scenarios. The coupled sewer-river-model InfoWorks CS-Hydrax/QSim 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 different CSO control strategies. The conducted scenario analysis indicates that the coupled sewer-river-model 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 (<2 mg/L) 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. 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. The extended sensitivity analysis shows that 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. Further, it has been shown that the entry and biodegradation of organic carbon compounds is the most important process for acute DO depletions after CSO. However, mixing of oxygen free spill water with the Berlin River Spree provokes an additional impairment of DO conditions. In the framework of this thesis, CSO impacts under different management strategies or climate change conditions are only assessed for a part of the Berlin combined sewer system and for one exemplary year. Before applying the presented instrument for planning specific measures it is proposed to expand the model area and simulated time period.

The usage of membranes in wastewater treatment often leads to problems with scaling and fouling, which results in an irreversible loss of membrane permeability. Various pretreatments as well as mechanical and chemical cleaning possibilities are described and evaluated in order to ensure continuous operation. The cleaning has been performed by a sequential backwash with filtrate. In addition, the membrane was cleaned chemically to restore the flux to an acceptable level. The effect of chemically enhanced backwash (CEB) and cleaning in place (CIP) has been considered in more detail. The UF membranes are typically cleaned by soaking in alkali, acids and/or oxidizing solutions. Sodium hydroxide (NaOH), sodium hypochlorite (NaOCl) and acid sulphur (H2SO4) were used as cleaning agents. Furthermore, the impact of pre-treatment by pre-ozonation and subsequent coagulation on the performance of a polyether sulphone ultrafiltration membrane has been investigated in a pilot plant. Ozone is used in water treatment for the oxidation of organic substances, which leads to a reduction of organic fouling. A subsequent coagulation is applied to form stable aggregates out of biopolymers, which are most relevant for membrane fouling in order to backwash them easily from the surface and the membrane pores. Both pre-treatments have an influence on an improved filtration performance. The scope of the current paper is to critically evaluate the impact on the hydraulic and chemical treatment of an organic membrane and to find out which cleaning strategy is the best against membrane fouling.

The main objective of this study was to identify design and operational differences between the Danish and the German waterworks in order to learn if the groundwater treatment in the Danish and German water supplies is comparable. Furthermore, the aim is to compile existing national designs to create an overview of Danish and German designs, respectively. The work was carried out with an emphasis on iron, manganese, and ammonium removal, and thus the aeration and filtration method were evaluated. Design differences in groundwater treatment between 19 Danish waterworks, 9 waterworks from Berlin and 3 from Hamburg were compiled. The design differences were revealed by questionnaires, review of standards, and an expert interview. The most significant difference was the design of the filters. In Denmark most of the waterworks apply two-stage filtration, where both pre- and afterfilters consist of quartz. A total of 69 % of the Danish filters used in the project had a supporting layer. The average height of the Danish filters was 1.05 meter and 0.66 meter for prefilter and afterfilter, respectively. In Berlin and Hamburg the most applied filtration type was a single filtration through a mono-media (quartz) filter with an average filter height of 2 meters. Half of them (47%) were constructed with a supporting layer. In all filtration types identified in this study the average German filter height exceeded the average Danish. While the grain size distribution in the effective filter layer was found to be relatively alike and within the range of 1 to 3 mm, with a slightly larger grain size in the Danish filters. The grain size found in the Danish supporting layer was much larger than in the German supporting layers. Furthermore, a special design for prefilters, so-called roughing filters, was identified in Copenhagen waterworks, where the grain size distribution was between 24 and 150 mm. Despite the generally smaller grain size, the average filter velocity was found to be slightly larger in the German filters. The application of aerators and the backwashing procedure in Denmark and Germany were found be different. In Denmark the most frequently found aerators are the stairs aerator and the multiple slat tray aerator, whilst in Germany the most applied forms of aerators are spray aerators and waterfall aerators. The backwashing procedure in Denmark was mainly found (37 %) as a combination of first an air flush, and then water, whilst the most frequently found (50 %) backwashing procedure in Germany was a combination with an additional simultaneous air and water flush in between the separate air and water flushes. The more extensive backwashing procedure in the German filter is believed to be connected to the higher height of the filters. Empty-bed contact time was calculated, and was found to be significantly shorter in the Danish filters, where the average empty-bed contact time was 23 minutes, compared to an average of 38 minutes in the German filters. The water chemistry suggested that the groundwater types found in Denmark, Berlin and Hamburg are similar, but this was not investigated further. The conclusion was that the filters in Denmark are not comparable to the filters found in Berlin and Hamburg, based on the fundamental differences in the construction concerning the filter height, grain size, and numbers of filter steps and the resulting diverse EBCT. The difference in filter designs needs to be considered when applying future research to both supplies.

The total phosphorus concentration (TP) in Berlin’s surface waters has to be decreased to 6090 µg/L to achieve good ecological conditions. Furthermore, securing the bathing water quality of surface waters gains more attention. The wastewater treatment plant (WWTP) in Ruhleben should be upgraded by tertiary treatment to reduce the TP concentration (< 80 µg/L) and the pathogen germ concentration in the WWTP effluent. The project OXERAM compares different filtration technologies with regard to their efficiency and applicability as tertiary treatment. In this thesis the combination of microsieve filtration and UV-disinfection has been investigated. Before this trial the microsieve was rebuilt after a one year operation period. The volume of the coagulation tank was reduced to 26 % (0.56 m³) of its initial volume. The coagulation stirrer was exchanged by a Turbomix TM, applying a constant G·t-value of 25 000. Additionally, the angle of the blades of the flocculation stirrer was changed, almost doubling the G-value (154 1/s.) Long term trials have shown that an average TP effluent concentration of 60 µg/L can be achieved through microsieve filtration (10 µm) with chemical pretreatment (2.0 mg Al/L PACl and 0.61 mg/L cationic polymer). 80 % of the grab samples had a TP concentration = 73 µg/L. An average effluent suspended solid concentration of 2.2 mg/L was achieved. The average residual Aluminum concentration was 0.35 mg/L. The increase of the G-value during coagulation and flocculation after the rebuild led to an increased energy demand of both stirrers. However, through the new hydraulic conditions, the average polymer dose was reduced by 65 % in comparison to the dynamic operation in summer 2011 and the hydraulic retention time during coagulation could be reduced to 1 minute at peak flow. Furthermore, the impact of applied energy during coagulation and flocculation was investigated. A reduction of the G·t-value during coagulation led to a higher SS effluent concentration of 25 % (2.8 mg/L). During flocculation a high G-value (153 1/s) was favorable for the microsieve performance. A lower backwash time and effluent turbidity were observed. As a result, the increased energy demand of the stirrers can be justified, alongside to the polymer and hydraulic retention time reduction, with an improved effluent water quality and a lower energy demand for the backwash. The UV-disinfection operated reliably after the microsieve filtration. The UV effluent concentration of Enterococci and E.Coli were always under the limit of quantification (15-38 MPN/100 mL), even at a fluence of 361 J/m². Coliphages (= 7 PFU/100 mL) were detected in the effluent of the UVdisinfection, when the calculated fluence was lower than 549 J/m². In this study it was demonstrated that the microsieve filtration with chemical pretreatment and a subsequent UV-disinfection represents an alternative as tertiary treatment. TP effluent values lower than 80 µg/L were reliably achieved. An excellent water quality accordingly to the EG Bathing Water Quality Framework Directive was attained through the subsequent UV-disinfection.