Für die Klärschlammbehandlung und -entsorgung von vier Kläranlagen (Ruhleben, Waßmannsdorf, Schönerlinde und Münchehofe) in Berlin wurden Energie- und Treibhausgasbilanzen jeweils mit und ohne Einbindung der Hydrothermalen Karbonisierung (HTC) erstellt. Als Methode diente die Ökobilanz mittels der Software Umberto 5.6. Hierzu wurden Stoffstrommodelle zur Quantifizierung der relevanten Stoff- und Energieströme bei der Schlammbehandlung, Prozesswasserbehandlung und Faulgasverwertung jeweils ohne und mit HTC (Reaktor, Entwässerung, Prozesswasserrückführung in Faulung bzw. Klärwerk) erstellt. Als Input-Daten dienten Messwerte der BWB, Laborversuche und Herstellerangaben. Aus den Ergebnissen wurden der kumulierte fossile Energieaufwand und das Treibhauspotential berechnet. Neben der Frage, inwieweit und durch welche wesentlichen Parameter die HTC die Bilanzen verbessert, wurde die Auswirkung der Ansäuerung bei der HTC, der Unterschied zwischen zwei HTC-Verfahren (TerraNova- und AVA-CO2) sowie die Ergebnisse einiger Pilotversuche hinsichtlich der Bilanzen ausgewertet. Bei den Klärwerken mit Faulung wurde eine deutliche Verbesserung der Energieund Treibhausgasbilanz durch die HTC bei Annahme einer guten Entwässerbarkeit (TR 65 %) festgestellt, in Ruhleben allerdings nur bei Ergänzung einer anaeroben HTC-Prozesswasserbehandlung mit Faulgasnutzung, dafür jedoch mit der größten Verbesserung. Hier kann der HTC-Wärmebedarf durch effiziente BHKWAbwärmenutzung zu 35 % gedeckt werden, bei den übrigen Klärwerken sind es >90 %. Die Verbesserung der Bilanzen kommt primär durch die zusätzliche Stromproduktion bzw. Braunkohlesubstitution bei der Verbrennung infolge des höheren Heizwertes, die Stromgewinnung durch das zusätzliche Faulgas (+16-19 %) und die reduzierten N2O-Emissionen bei der Monoverbrennung zustande. Die Coverbrennung zeigt stets deutlich bessere Energiebilanzen als die Monoverbrennung. Die Ansäuerung bei der HTC bewirkt eine geringere Methanausbeute aus dem Prozesswasser sowie eine geringe HTC-Kohle-Massenausbeute und damit eine Verschlechterung der Bilanzen. Bezüglich der Ursachen besteht noch Klärungsbedarf. Das AVA-CO2-Verfahren hat nur eine geringfügige Methanausbeute, verbunden mit einem höheren Erdgasbedarf, jedoch einen höheren Heizwert und Massenausbeute der HTC-Kohle. Dadurch ist es dem TerraNova-Verfahren hinsichtlich der Bilanzen nur bei der Coverbrennung überlegen, bei der Monoverbrennung ist es umgekehrt. In den Pilotversuchen fiel der Entwässerungsgrad geringer aus als angenommen (TS 44-51 %). Dadurch sinkt der nutzbare Heizwert und die Bilanzen verschlechtern sich entsprechend. Weitere Pilotversuche sind empfehlenswert. Refraktäre Verbindungen im Prozesswasser verursachen eine zusätzliche CSBBelastung des Ablaufs (+7-12 mg/l). In Waßmannsdorf würde der Überwachungswert überschritten, in den übrigen Klärwerken würde er im Mittel eingehalten.

Rain water runoff is the largest untreated source of potentially high loads of micro pollutants to urban surface waters. Given first findings it can be expected that new rainwater based micro pollutants will be included in future lists of priority substances of the EU Water Framework Directive (WFD). Knowledge of the type and amount of micro pollutants is (therefore) pivotal for enabling good management. Pollutant concentrations depend heavily on rain event characteristics such as rain depth, mean rain rate, intensity, duration and dry-weather-period. As rainfall is usually reported to fall in events and is separated by rainless intervals of a certain duration, the minimum interevent time (MIT) plays a major role within the criteria for defining such rain events. Surprisingly little attention has been paid to the importance of rain event definitions in similar published works, which limits the significance of the results and their comparability to other researches. That is why this work aims to identify independent rain events from a pluviograph record with the help of further hydraulic data. It is also the goal to examine rainfall characteristics of (5) sub-catchments within in the larger catchment Berlin and their sensibility through the variation of rain event definitions, like the very important Minimum-Inter-event Time Definition (MITD). Several rain gauges close-by as well as sensors to measure the water level and the flow inside a storm water sewer of a separated sewage system supply the necessary data. Additionally a number of criteria, found in literature, help to identify the most stable definition of a rain event for these catchments. It is also the intention to set the basis for further analysis (within the project this thesis is realized in) in order to generate the most adequate concentration data of micro pollutants in Berlin’s urban rain water runoff, as this definition will play a major role for further project analysis. Moreover this work intents to emphasize the relevance of the selection and documentation of rain event criteria in studies that apply event-based data analysis.

Die europäische Wasserrahmenrichtlinie (EU-WRRL) aus dem Jahr 2000 schreibt eine Verbesserung der Gewässerqualität auf einen „guten ökologischen Zustand“ vor. Bis 2015 konnte dieses Ziel jedoch nicht erreicht werden. Der Überschuss an Nährstoffen in Oberflächengewässern ist ein Aspekt, der zum Misserfolg des Vorhabens beitrug. Eine Rolle spielen hierbei die Nährstofffrachten, die aus urbanen Gebieten über die Kanalisation in die Gewässer gelangen. In dieser Arbeit werden daher Maßnahmen untersucht, die zur Reduktion der Nährstoffemissionen aus dem Kanalnetz dienen. Es wird eine Ökobilanz zu ausgewählten Maßnahmen der zentralen Regenwasserbewirtschaftung durchgeführt. Die Maßnahmen werden hinsichtlich ihres ökologischen Aufwandes (Materialbedarf, Transport, Energiebedarf, etc.) und ihres ökologischen Nutzens (Nährstoffreduktion) analysiert. Dabei wird zwischen Maßnahmen im Trenn- und Mischsystem unterschieden. Im Trennsystem wer-den ein Retentionsbodenfilter (RBF), drei unterschiedliche Regenklärbecken (RKB), ein Lamellenab-scheider (LA) und eine Nachrüstung eines RKB mittels Lamellen untersucht. Im Mischsystem erfolgt eine Analyse von einem Regenüberlaufbecken (RÜB), einem Stauraumkanal (SK) und drei Stauraum-aktivierungsmaßnahmen. Zu diesen gehören eine Abflusssteuerung durch eine eingebaute Drossel-anlage und zwei Umbaumaßnahmen zur Nutzung des Speichervolumens von Überlaufkanälen. Der Vollständigkeit halber wurden ein vereinfachtes Modell einer Großkläranlage, einer Schlammbehand-lung sowie einer Klärschlammverbrennungsanlage (KSVA) in die Betrachtung miteinbezogen. Um eine Aussage über potentielle Umweltauswirkungen treffen zu können, werden für die Wirkungsab-schätzung unter anderem das Treibhauspotential (GWP), die marine (MEP) und Süßwasser Eutro-phierung (FEP) sowie zwei Toxizitätspotentiale betrachtet. Zudem erfolgt eine Analyse zum kumulier-ten Energieaufwand (KEA) fossiler und nuklearer Energieträger. In den Ergebnissen stellt sich die Infrastruktur als maßgeblicher Faktor für den ökologischen Aufwand heraus. Zudem spielt insbesondere im Mischsystem die zusätzlichen Aufwendungen auf der Kläranla-ge eine große Rolle. Der Aufwand für den Betrieb und die Wartung der Maßnahmen hingegen ist vergleichsweise gering. Im Trennsystem besitzen der Retentionsbodenfilter und der Lamellenab-scheider die geringsten negativen Umweltauswirkungen. Der Bau von Regenklärbecken geht diesbe-züglich mit weitaus höheren Auswirkungen einher. Im Mischsystem sind die Maßnahmen der Stau-raumaktivierung mit geringeren Umweltauswirkungen behaftet, als die Maßnahmen zum Bau neuer Speichervolumina.

The Wilmersdorf Catchment, part of the Berlin combined sewer system, faces severe problems regarding combined sewer overflows (CSO) and flooding which might worsen due to climate change and ongoing urbanisation. Rather than investing in costly adaptations, the goal of this study is to improve the utilisation of the existing storage capacity of the network in order to reduce CSO and flooding. The potential for optimisation was investigated by means of performance criteria (CSO volume, overflow peak and duration, flood volume and duration, number of flooded nodes) defined to assess the severity of CSO and flood events. This study takes a double interest in including dynamic and static adaptive measures to examine on one hand the potential improvement of the real-time control (RTC) strategy, and on the other hand the possible adaptation of existing structures in the network. To investigate these measures, a 1D-hydrodynamic model of the sewer network planned for 2020 was provided within the modelling package InfoWorks CS. The indicators were used to characterise the performance of the status-quo network as well as each implemented measure under a range of design storms. Three successful measures – the increase of a throttle pipe diameter and the elevation of two different overflow crests were identified to be effective for CSO reduction. On the other hand, adaptations of the RTC strategy did not lead to an improvement of the CSO aspect. The results of the simulations involving individual measures revealed that an optimisation of the network by making minor adjustments is possible. Indeed, CSO volume is almost halved under a 3-month rainfall after one overflow crest was elevated of 80 cm. Furthermore, a combination of the three best measures could reduce CSO volume by almost 60% for the same rainfall intensity. However, even though no significant worsening of flooding occurs, the main limitation of this type of measures is their inability to cope with flooding issues. Additional research should be conducted to complete the preliminary results that constitute this thesis and to fully determine the potential of the catchment, especially regarding the flooding aspect. In particular, decentralised measures that increase the pervious fraction of the surface could supplement this study.

Due to intensive aeration in the activated sludge basins, a significant part of the organic matter in the wastewater often expressed as chemical oxygen demand (COD) is mineralized to the greenhouse gas CO2. Therefore the organic content in municipal wastewater is yet a widely untapped source of renewable energy. The Carismo project vision is to reduce the specific energy demand with a new treatment scheme based on a low energy microsieve separation process and at the same time, increase the specific energy recovery with an advanced separation of the organic fraction which is valorized in a digester. Therefore two treatment schemes were evaluated at lab scale and pilot scale with real wastewater. The raw wastewater contained a high COD concentration of 1000 mg/l. The first scheme treated the raw wastewater with a coagulation and flocculation step before a microsieve separation with a drum filter at 100 µm. The second scheme was similar to the first one with an additional MBBR (Moving Bed Biofilm Reactor) installed upstream the coagulation tank. The specific goal of the microsieve process was to increase the organic carbon extraction rate in scheme 1 to 60–80 %. The Pilot trial results showed an average COD extraction of 73–81 %. The average suspended solids (SS) removal was > 95 %. The soluble phosphorus removal was between 15 % and 70 % depending on the coagulant type and dose. With 20 mg Al/l, the effluent phosphorous concentration was around 2 mg/l. The MBBR upstream increased the COD transfer in the sludge by 3–8 %, but simultaneously the mineralization decreased the yield for the biogas process. This and the additional energy consumption of the aeration speaks against the separation process with an upstream MBBR.

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.

Annually, about two million mega grams of dry solids (DS) of sewage sludge accumulate in wastewater treatment in Germany. According to the Statistical Federal Office (Destatis, 2013), 1,846,441 mega grams DS of sewage sludge were utilized in 2012. Besides incineration, the exploitation of sewage sludge in agriculture as fertilizer plays a significant role. In 2012, about 600,000 (544,065) mega grams of dry sewage sludge were applied on agriculturally or horticulturally used soils, which corresponds to 30.0 % of total amount (Bundesamt, 2011, AbfKlärV, 1992). Before disposing, the sewage sludge must be dewatered which is usually executed using synthetic flocculation aids like polyacrylamide (PAM) and its derivatives (Tuan et al., 2012). According to the fertilizer ordinance, as of 01/01/2017 20 % of all compounds as well as the end product of the used synthetic flocculation aids must be degraded two years after agricultural application (DüMV, 2012). Despite this regulation, an accumulation of polyacrylamide in the soil can be expected, since it is allowed to apply 5 mega grams DS of sewage sludge per hectare in 5 years (AbfKlärV, 1992). Seybold (1994) suggests that PAM is mostly resistant to microbial decomposition and mainly physically degraded. Not the PAM but its monomer (acrylamide) is known for its neurotoxicity (LoPachin and Gavin, 2012). Even if it does not permanently accumulate in soil, a potential toxicity exists. Therefore it is desirable to substitute the synthetic polyelectrolyte by a natural based and easily bio-degradable alternative flocculation aid. Several studies investigating the flocculation properties of cationic starch have been carried out (Rath and Singh, 1997, Khalil and Aly, 2001, Haack et al., 2002, Schwarz et al., 2006, Hebeish et al., 2010, Wang et al., 2013) but not in combination as nutrient incorporating fertilizer. The scarcity of phosphate rock sources has been an important issue in the last decades (Pinnekamp et al., 2007, Kabbe, 2013) as phosphate is a key nutrient for life on earth. As Kabbe (2013) states: “It is the key element in our genome, cellular membranes, skeleton and molecule adenosine triphosphate (ATP), the organism’s main energy storage.” Phosphorus is a non-substitutable nutrient in agriculture. An application of phosphorus fertilizer manufactured from non-renewable phosphate rock due to high crop yields is inevitable (Syers et al., 2011). Approximately 80 % of mined phosphorus are used for the fertilizer industry worldwide, in Germany even 85 % (Pinnekamp et al., 2007). Cordell et al. (2009) points out that the current global resources will be depleted in 50 to 100 years. For that reason, fostering of phosphorus recovery has become a current topic in the last years. So the European project P-REX – Sustainable Sewage Sludge Management fostering Phosphorus Recovery and Energy Efficiency was coined in September 2012. 16 European partners managed by project leader Dr Christian Kabbe from Berlin Centre of Competence for Water gGmbH work on 6 different working areas trying to close the phosphorus loop (shown in Fig. 1). Besides phosphorus recovery technologies from sludge processes or incineration ash out of sewage sludge, direct application on arable land is one branch of the phosphorus cycle. Within the working area 3 (WA3), the demonstration of applicability of green polymers for sludge dewatering step is one working package (P-REX, 2013). Within P-REX, this research attempts to combine phosphorus recovery and substitution of synthetic flocculation aids using natural based (green) polymers within sewage sludge treatment. The flocculation properties of a starch based cationic green polymer will be examined by measuring selected dewaterability indicators. Diverse sludge types from 3 different German wastewater treatment plants will be analysed after applying polyacrylamide/starch blends with defined ratios. As to phosphorus recovery, the phosphate contents of treated sludge water will be measured and a possible nutrient incorporation will be surveyed.