The management of urban wastewater systems and the associated modelling of these systems has become indispensable in today's world. In order for these models to represent reality as accurately as possible, a reliable calibration is essential. Water level data is used as a standard, but due to expensive sensors and harsh conditions in the sewer, data can only be collected at a few key points of the system. One novel solution, that has experienced an upswing in recent years, is collecting data using low-cost temperature sensors. Two sensors are needed; one is placed in the stream; the other is placed at the crest of the weir. In the case of dry weather, the sensor measures the air phase, whereas, in the case of Combined Sewer Overflow (CSO), the discharged storm and wastewater is measured. The start and end of a CSO event can be determined via the merging of measured temperature values in both points of the overflow structure. Due to this method, the duration of CSO events in a sewer system can be detected.

In this work, the potential benefits of this novel method for model calibration are assessed. Therefore, autocalibration runs with water level data and fictional temperature data were carried out via OSTRICH for a SWMM model located in Berlin. Furthermore, calibration runs with a different number of measuring sites were performed, to evaluate the amount of necessary measuring sites for a reliable calibration. In order to be able to compare the different approaches, a calibration period of 19 events was first required for the respective datatype. Next, a validation period which consisted of 18 events was carried out and evaluated by the R² of three water level measuring sites for both approaches to ensure comparability. It was revealed that the calibration with duration data based on temperature sensors was able to achieve results as good as the conventional approach using water level data. Due to low spatial distribution of the measuring sites in the model, it could not be finally answered if more measuring sites would yield to even better results. However, already with one measuring site, promising calibration outcomes could be achieved and thus, offers an alternative for water utilities and practitioners.

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.

An innovative tool for modeling the specific flood volume was presented that can be applied to assess the need for stormwater network modernization as well as for advanced flood risk assessment. Field measurements for a catchment area in Kielce, Poland, were used to apply the model and demonstrate its usefulness. This model extends the capability of recently developed statistical and machine learning hydrodynamic models developed from multiple runs of the US Environmental Protection Agency (EPA) Storm Water Management Model (SWMM). The extensions enable the inclusion of (1) the characteristics of the catchment and its stormwater network, calibrated model parameters expressing catchment retention, and the capacity of the sewer system; (2) extended sensitivity analysis; and (3) risk analysis. Sensitivity coefficients of calibrated model parameters include correction coefficients for percentage area, flow path, depth of storage, and impervious area; Manning roughness coefficients for impervious areas; and Manning roughness coefficients for sewer channels. Sensitivity coefficients were determined with respect to rainfall intensity and characteristics of the catchment and stormwater network. Extended sensitivity analysis enabled an evaluation of the variability in the specific flood volume and sensitivity coefficients within a catchment, in order to identify the most vulnerable areas threatened by flooding. Thus, the model can be used to identify areas particularly susceptible to stormwater network failure and the sections of the network where corrective action should be taken to reduce the probability of system failure. The simulator developed to determine the specific flood volume represents an alternative approach to the SWMM that, unlike current approaches, can be calibrated with limited topological data availability; therefore, the aforementioned simulator incurs a lower cost due to the lower number and lower specificity of data required.

This report summarises the theoretical design of a degasification plant to recover ammonia and carbon dioxide from organic residues, such as agricultural digestates, manure and municipal/industrial wastewater. Heat and water management had been identified as one crucial factor to optimise during this research. The chemical and physical parameters reveal the high tendency of ammonia towards water phase and underline the difficulty in ammonia stripping. Besides temperature, the volumetric gas-liquid ratio had been identified as most important factors. Regarding pH-value it had been observed, that a further increase is not sufficient once pH 9 is reached. Applied absolute pressure also has been identified of lower importance, compared to temperature and volumetric gas-liquid ratio. The latter three parameters are influencing evaporation and heat management in the desorption stage. A design model from literature according to Onda showed good correlation with the practical experiments including packings. Other column fillings as cones lead to operational problems. The understanding of the exact relations in column design are further used to design a cost-efficient process with low carbon footprint. The practical tests, as such, were reproducible, however the batch operation and limitations in the column design resulted in a limited transferability towards large scale plants. In terms of the absorption stage, the pilot needs to be further optimised to reach sufficient recovery rates. An absorption of ammonia and carbon dioxide under use of gypsum is favoured to also recover carbon dioxide and to avoid sulfuric acid dosing. In that term further tests and optimisation is needed, to have a fully quantifiable pilot system. The integration of a measure-control system is a further development step. In conclusion, the degasification process with low pressure (vacuum) reveals benefits compared to conventional air stripping in terms of heat management and the necessary gas-liquid-ratio, which has effects on column diameter and eventually column height. The necessity of aggressive chemicals dosage (as caustic in desorption) or acid (in absorption) is in view of the authors not given, hence cheap and safe alternatives (e.g. CO2 stripping) and gypsum dosage as alternative sulphur source work sufficient.