This paper investigates the robustness of one innovative model-based method for leak detection, namely the Dual Model. We evaluate the algorithm’s performance under various leakage scenarios in the L-Town network, despite uncertainties and model mismatches in (i) base demand, (ii) pipe roughness, (iii) the number of sensors, and (iv) network topology. Our investigation results indicate that the Dual Model is highly sensitive to discrepancies in the first three parameters. However, the impact can be mitigated through sensor-specific calibration, such as adjusting sensor elevations. Moreover, the Dual Model has demonstrated robustness to minor topology mismatches, like those introduced by closed valves.

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.

Der vorliegende Forschungsbericht befasst sich mit den derzeitigen Unsicherheiten bezüglich der technischen Nutzungsdauer und des Alterungsverhaltens der gängigsten Renovierungsmethode in Kanalnetzen, dem Cured in Place Pipe (CIPP) Schlauchlining. Ziel dieser Arbeit ist die Entwicklung einer fundierten Datengrundlage für eine Schlauchliner-Überlebenskurve für die Anwendung in Alterungsmodellen. Das methodische Vorgehen umfasst (i) eine Literaturrecherche, (ii) Interviews mit Kanalsanierungs-Expert:innen sowie (iii) eine Auswertung von Daten der Berliner Wasserbetriebe zur Erstellung einer aktualisierten und geeigneten Datengrundlage für die Überlebenskurven. Dabei zeigen sich in der Auswertung der Literatur und den Interviews mehrheitliche Schätzungen der Nutzungsdauer von Schlauchlinern von über 50 Jahren. Die Untersuchung zeigt jedoch auch, dass diese von vielen Faktoren beeinflusst ist und ein Mangel an belastbaren Daten besteht. Weitere Untersuchungen an langjährig betrieben Schlauchlinern sind daher zwingend notwendig. Der Einbau, insbesondere der Aushärtungsprozess hat sich als Haupteinfluss für Defekte und Mängel an Schlauchlinern gezeigt. Eine Standardisierung der Schadenserfassung und Zustandsbeurteilung von schlauchlinerspezifischen Schäden sowie die Etablierung zerstörungsfreier Inspektionsmethoden sind erforderlich, um das Alterungsverhalten zukünftig besser zu verstehen. Empfehlungen umfassen die Verbesserung der Datenerhebung während des Betriebs, Ein- und Ausbaus von Schlauchlinern, die Erweiterung der Qualitätssicherung beim Einbau, sowie die Untersuchung von Schadenseinflüssen auf die Nutzungsdauer und den Erfahrungsaustausch zwischen Betreibern.

An innovative circular economy (CE) system was implemented at the wastewater treatment plant (WWTP) in Brunswick. The performance of the CE system was evaluated for 4 years: the thermal pressure hydrolysis enhanced the methane production by 18% and increased the digestate dewaterability by 14%. Refractory COD formed in thermal hydrolysis and increased the COD concentration in the WWTP effluent by 4 mg L−1 while still complying with the legal threshold. Struvite production reached high phosphorus recovery rates of >80% with a Mg:P molar ratio ≥0.8. Nitrogen was successfully recovered as ammonium sulfate with high recovery rates of 85–97%. The chemical analyses of secondary fertilizers showed a low pollutant content, posing low risks to soil and groundwater ecosystems. The total carbon footprint of the WWTP decreased due to enhanced biogas production, the recovery of renewable fertilizers and a further reduction of nitrous oxide emissions. Using green energy will be crucial to reach carbon neutrality for the entire WWTP.