Kompetenzzentrum Wasser Berlin gGmbH (KWB) would like to voluntarily draw up a greenhouse gas balance sheet for the year 2023. The aim is to develop a better awareness of the main emitters and options for action to reduce them. The higher travel volume before covid 19 pandemic and the influences of the change of location within Berlin are to be highlighted. The Greenhouse Gas Protocol is used for balancing. Depending on the data situation for the applicable category, calculation methods such as fuel-based calculation for Scope 1 (direct emissions from the vehicle fleet), supplier- and average-based methods for Scope 2 (indirect emissions from purchased electricity and heat) and spend-, average- and distance-based methods for Scope 3 (upstream and downstream emissions) are used. The data comes from the administration, supplier information, Exiobase at Climatiq, Ecoinvent, the Umweltbundesamt, an employee survey via Jotform and individual inquiries. The operating cost statements were used from the previous year. The KWB's overall balance in the 2023 financial year resulted in 148 t of CO2e emissions at the old location. Scope 1 is the third smallest emitter of all sub-categories with approx. 4.5 t CO2e emissions. Scope 2 is in the middle of the emitters with approx. 10.6 t CO2e emissions. Scope 3 is the largest emitter with 133 tons of CO2e emissions and thus accounts for almost 90% of the total balance. Unexpectedly, employee commuting is not a major emitter, as the use of bicycles and local public transport is very high. Business travel, on the other hand, is the second largest emitter, contributing a significant 19 % to the balance sheet, with 23 flights representing the main emitter of business travel with 15.2 t CO2e emissions, 74,500 km traveled and over 50 % of CO2e emissions. In comparison, 114 train journey segments account for only 15% of CO2e emissions from business trips. At almost twice the distance traveled, approximately 134,500 km, the amount of CO2e is only 4.2 tons. Trip segments refer to individual parts of a trip that were recorded separately due to different means of transportation or travel times. The pilot systems and samplers are the KWB's largest source of CO2e emissions, accounting for approx. 35% and approx. 50 tons of CO2e emissions in the overall balance due to their high electricity consumption. IT is the third largest emitter in the overall balance with 15.2 tons of CO2e emissions and 10%. A reduction in air travel in favor of train travel would have reduced the overall GHG balance by 5 % in 2023. As a result of the change of location, the energy consumed for heating and cooling at the site is only a third of the previous requirement despite 50% more office space. At almost 3 tons of CO2e emissions, the GHG emissions at both sites are almost the same, although the supplier-specific CO2e emission factor is three times higher at the new site. With 3.8 tons of CO2e emissions per employee, KWB emits slightly more than half the emissions of other companies in the service sector.

Die Wiederverwendung von gereinigtem Abwasser zur landwirtschaftlichen Bewässerung ist eine vielversprechende Lösung, um die landwirtschaftliche Produktivität in Zeiten des Klimawandels zu erhalten. Allerdings sind mit dieser Praxis auch Umweltrisiken verbunden, da gereinigtes Abwasser, Rückstände von Krankheitserregern und Schadstoffen, darunter vor allem Spurenstoffen enthalten kann. Eine weitergehende Abwasserreinigung ist daher entscheidend, um potentielle Risiken zu minimieren. Forschungsprojekte wie FlexTreat arbeiten an technischen Lösungen zur sicheren Wasserwiederverwendung. Diese Szenarienanalyse zeigt, dass die Bewässerungsmenge und die Art der Abwasserbehandlung wesentliche Faktoren für den Eintrag von Spurenstoffen ins Grundwasser sind. Eine bedarfsgerechte Bewässerung während der Vegetationsperiode kann die benötigte Wassermenge reduzieren und den Spurenstoffeintrag in das Grundwasser verringern. Zusätzlich kann eine höhere Bewässerungsfrequenz den Spurenstoffeintrag weiter reduzieren, wobei sich die Summe der verwendeten Bewässerungsmenge nicht erhöht. Diese Erkenntnisse unterstreichen die Bedeutung von Managementansätzen, die sowohl technische Lösungen als auch angepasste Bewässerungspraktiken umfassen, um eine sichere Wasserwiederverwendung zu gewährleisten und Grundwasserbelastungen zu minimieren.

This bachelor thesis examines the influence of precipitation events and urban stormwater runoff on the concentrations of persistent and mobile substances (PM) in Berlin's surface waters. The analysis includes concentrations of 69 substances from four substance groups (VOCs, PAHs, PFAS, pesticides) that were recorded at 24 surface water sampling sites. Using precipitation data from 32 locations in Berlin, the concentrations were categorized according to dry weather, rain, and heavy rain influence. Statistical analyses for comparing these categories were performed using the Kruskal-Wallis and Dunn tests. Additionally, the concentrations in the surface waters were compared to those in Berlin's stormwater runoff using box-whisker plots.

13 of the investigated substances show significantly higher concentrations during rainfall or heavy rain events. This can be attributed to the input of these substances into surface waters through rainwater runoff. Particularly PAHs show notable concentration increases in Berlin's surface waters during precipitation events. PFOA and PFOS, two representatives of the PFAS group, exhibit a more complex behavior pattern depending on precipitation events. During light rainfall, their concentrations in surface waters decrease, while heavy rain events lead to increased concentrations. For pesticides and VOCs, the results are less conclusive, partly due to limited data availability.

This analysis provides valuable insights into the transport of various substance groups within the urban water cycle. The findings expand the scientific basis for developing targeted protection measures for urban waters.

A new generation of integrated fixed-film activated sludge (IFAS) systems, merging the biofilm of the root zone from aquatic plants into the activated sludgeprocess, has increasingly gained attention in recent years as a potential alternative to conventional wastewater treatment systems. However, there is a lack of understanding of the broader environmental impact of this emerging technology and how it compares to traditional concepts of wastewater treatment. In this research, we address this gap by conducting a comparative Life Cycle Assessment (LCA) with three reference scenarios, based on design simulations in seven midpoint impact categories. The entire novel wastewater treatment system at a small to medium-sized brewery in the Netherlands, including sludge disposal, resulted in net values of 29.2 MJ, 1.9 kg CO2-eq., 3.4 g  OX-eq., 0.1 mg CFC11- eq., 4.0 g SO2-eq., 0.3 g P-eq., and 1.9 N-eq. per m3 wastewater treated, under categories CED, GWP, POFP, ODP, TAP, FEP, and MEP, respectively. Compared to aerated SBR systems, the new system demonstrated higher environmental burdens in CED (120%), GWP (122%), POFP (125%), ODP (123%), and TAP (133%). This study provides evidence that these impacts on the environment mainly depend on the technology’s current electricity demand, while additional improvements can also be achieved by lowering the chemical and nutrient demand of the system. The comparison to a potential anaerobic treatment opportunity for the brewery wastewater with an EGSB reactor, exacerbated the previously identified shortcomings of the new technology, since the crediting of biogas allowed a complete offset of the total environmental impact measured by the GWP, CED, and ODP. Our findings suggest that additional water recovery concepts with subsequent nanofiltration systems, aimed at preserving natural water resources, may offer no competitive advantage for the GWP, CED, POFP, OPD, and TAP, if the electricity demand (1.17 kWh per provided m3 reused water) surpasses the benefit of water reuse. However, it is important to note that the new technologies provide their own set of benefits, such as a reduced impact on freshwater and marine eutrophication, due to the high  nutrient uptake capability. Our research provides implications for practitioners and researchers seeking to understand the environmental impact associated with plant root equipped IFAS, while implicit design assumptions may limit the ability to generalise findings on real-world scenarios.

Durch eine mehrstufige Behandlung von Biomasse unter Luftabschluss, kommt es in Biogasanlagen zur Produktion von Biogas. Als Nebenprodukt entstehen dabei ebenso Biogasgärreste, welche durch die stoffliche Zusammensetzung hochwertiges Düngemittel darstellen. Eine verbesserte Gärrestenutzung kann zur Steigerung des Nährstoffmanagements führen. Der wichtigste Nährstoff für Nutzpflanzen ist Stickstoff. Deshalb macht es Sinn Ammoniumstickstoff aus Abwässern, Gülle und anderen Gärresten zurückzugewinnen. Eine Möglichkeit ist die sogenannte AmmoniakStrippung. In der Nachbehandlung wird Ammoniumstickstoff in einem Gaswäscher erneut aufkonzentriert und somit das Ammoniak in wieder verwertbarer Form zurückgewonnen. Um die Inbetriebnahme eines Gaswäschers zu realisieren, wurde ein Messprogramm erstellt. Durch sieben Versuchsreihen und einer Variation von Stellparametern wurden zunächst die Eliminationsraten in einer Stripp-Kolonne betrachtet. Des Weiteren wurde die Anreicherung im Gegenstromverfahren durch absorptive Prozesse von Ammoniumstickstoff und Kohlenstoffdioxid in einem Gaswäscher bilanziert und durch Gegenüberstellung der Verfahren Auswertungen hinsichtlich der quantitativen Rückgewinnung erzielt. Außerdem wurde als Optimierungsoption eine theoretische Kolonnenauslegung betrachtet. Der Schwerpunkt lag dabei auf der Bestimmung der Füllkörperhöhe und des nassen Druckverlusts. Weiterhin wurden auf Basis dieser Ergebnisse Untersuchungen zu unterschiedlichen Füllkörpermaterialien durchgeführt.

Um die Trennleistung einer Vakuumentgasungsanlage zu optimieren, wurde mit dem Einsatz von Füllkörpern der Ammoniumstickstoffanteil von separiertem Gärrest im Gegenstromverfahren mit Strippluft abgereichert. Drei Füllkörperarten unterschiedlicher Hersteller wurden bei gleichen Betriebsbedingungen untersucht. Die Effizienz konnte so bei einer stabilen Prozessführung gesteigert werden. Außerdem wurde eine theoretische Kolonnenauslegung durchgeführt, die die Bestimmung der Füllkörperhöhe und des nassen Druckverlusts umfasste. Aus diesen Ergebnissen lassen sich Vorhersagen hinsichtlich der Ausgangskonzentrationen von Ammoniumstickstoff prognostizieren. Aus den Experimenten und der theoretischen Kolonnenauslegung konnte eine optimierte Anlagenkonfiguration abgeleitet werden.

Technical nitrogen (N) recovery from biogas digestate via vacuum degasification (VD) of ammonia is an important task with regards to environmental issues and economic reasons. There has not yet been much research on VD, but compared to conventional stripping methods energy costs might be reduced. In the frame of the EU project ”Circular Agronomics” a VD pilot plant for N recovery from biogas digestate was built. This study aims on optimizing the pilot plant with special regards to the scrubber, where the N fertilizer is formed. The plant was operated at 310 mbar absolute pressure, 150 L · h−1 recirculation rate and 35 kg total water mass. Two different conditions were examined: condition 1) 70◦C, gas to liquid ratio (G/L) 20:1, pH 9 and condition 2) 50◦C, G/L 33:1, pH 10. A total ammonium nitrogen (TAN) elimination of 93% for condition 1 and 73% for condition 2 was achieved. Conducting the experiments a high amount of water was evaporated (25% for condition 1 and 5% for condition 2). The high water evaporation leads to a low TAN/water ratio in the gas stream of 0.4−1.2 (condition 1) and 1.6−2.8 mol · L−1 (condition 2) respectively. A low TAN/water ratio is disadvantageous, as it results in a dilution of the N fertilizer, that is being formed in the subsequent scrubber. Besides, it was found, that the plant loses high amounts of energy in form of latent heat due to water evaporation and requires more favorable energy recovery.