Publications

Abstract

Micropollutants (MPs) in wastewater pose a growing concern for their potential adverse effects on the receiving aquatic environment, and some countries have started requiring that wastewater treatment plants remove them to a certain extent. Broad spectrum advanced treatment processes, such as ozonation, activated carbon or their combination, are expected to yield a significant reduction in the toxicity of effluents. Here we quantify the reduction of effluent toxicity potentially achieved by implementing these advanced treatment solutions in a selection of the European wastewater treatment plants. To this end, we refer to a list of “total pollution proxy substances” (TPPS) composed of 1337 chemicals commonly found in wastewater effluents according to a compilation of datasets of measured concentrations. We consider these substances as an approximation of the “chemical universe” impinging on the European wastewater system. We evaluate the fate of the TPPS in conventional and advanced treatment plants using a compilation of experimental physicochemical properties that describe their sorption, volatilization and biodegradation during activated sludge treatment, as well as known removal efficiency in ozonation and activated carbon treatment, while filling the gaps through in silico prediction models. We estimate that the discharge of micropollutants with wastewater effluents in the European Union has a cumulative MP toxicity to the environment equal to the discharge of untreated wastewater of ca. 160 million population equivalents (PE), i.e. about 30 % of the generated wastewater in the EU. If all plants above a capacity of 100,000 PE were equipped with advanced treatment, we show that this load would be reduced to about 95 million PE. In addition, implementing advanced treatment in wastewater plants above 10,000 PE discharging to water bodies with an average dilution ratio smaller than 10 would yield a widespread improvement in terms of exposure of freshwater ecosystems to micropollutants, almost halving the part of the stream network exposed to the highest toxic risks. Our analysis provides background for a cost-effectiveness appraisal of advanced treatment “at the end of the pipe”, which could lead to optimized interventions. This should not be regarded as a stand-alone solution, but as a complement to policies for the control of emissions at the source for the most problematic micropollutants.

Abstract

The zeolite clinoptilolite (CLI) is known to be a very good ion exchanger, as it consists of a three-dimensional structure formed of AlO4− and SiO4 tetrahedral, which are connected by a common oxygen atom. The micropores formed by this structure (with free diameters in the range of 0.40 nm and 0.72 nm) are fine enough to allow cations and water molecules to enter and be exchanged. CLI is a suitable, inexpensive, and globally available material for removing ammonium from highly-concentrated wastewater and is proven to be selective in ammonium uptake and regeneration since no effect of the provenance of the ammonium (matrix-free NH4Cl solution or sludge water) could be found. However, regeneration of the clinoptilolite is necessary to recover the adsorbed ammonium for further use and restore its capability for ion exchange. Within this work, the method by which clinoptilolite, loaded with ammonium (q = 8.1–16.6 mg/g) from different sludge waters and ammonium chloride solution, can be regenerated to yield a stoichiometric ammonium sulfate solution (ASS), that could be used, e.g., as a fertilizer, was investigated. A regeneration solution containing Na2SO4 (0.25 n(Na2SO4)/n(NH4+ads)) with a varying NaOH ratio (0–2.14 n(NaOH)/n(NH4+ads)) was tested. To obtain a high ammonium concentration in the eluate, a large mass fraction ω of 284 g/kg of CLI in the regeneration solution was applied. The effects of different ammonium loads, different origins of the ammonium, and residual moisture on the necessary components of the regeneration solution, in which an ASS is obtained within a contact time of 10 min at 22 °C, were studied. A stoichiometric ASS from CLI loaded up to a maximum of 13.5 mg/g was obtained with a mixture of 0.25 n(Na2SO4)/n(NH4+ads) together with 0.8–1.0 n(NaOH)/n(NH4+ads) for dry CLI, and 0.75 n(NaOH)/n(NH4+ads) for CLI with residual moisture.

Abstract

With the 2030Agenda for Sustainable Development, the United Nations have established a catalog of 17 Sustainable Development Goals (SDGs) to achieve a better and more sustainable future for all by 2030. One important aspect, formulated as Goal 6, is ensuring the availability and sustainable management of water and sanitation for all. Achieving SDG 6 represents a chal-lenge for planning, governance, and water management, especially in prosperous water-scarce regions, where water demand rises steadily and outgrows sustainable supply.Over a 3,5-year period, the joint project TRUST (“Sustainable, fair and environmentally sound drinking water supply for prosperous regions with water shortage: Developing solutions and plan-ning tools for achieving the Sustainable Development Goals using the river catchments of the region Lima/Peru as an example”) has developed inter- and transdisciplinary concepts for drin-king water use, safe wastewater disposal and water reuse to support achieving SDG 6 in water scarce regions, using the example of the catchment area of the Río Lurín, Peru. This report presents the approaches and results developed in the TRUST project. The approaches combine natural, engineering and social science expertise from research and practice, starting at the local level and scaled up to the level of catchment areas. They are structured along the do-mains of “water resources”, “water use” and “water management”. The domains are closely inter-linked and support working towards the development of integrated water management concepts. Each of these domains begins with the set-up of an information base, followed by the conduction of analysis and the development of concepts. It concludes with the derivation of lessons learned and recommendations for each of the domains. Generating a sound multidisciplinary information base is key for water resources planning and conduction of analysis. Installing a small number of monitoring stations at the right locations allows to get important insights on water quantity. Establishing and maintaining a monitoring network for water quantity is a challenging task in remote and mountainous areas, requiring long-term efforts and commitment. However, long time series are important to run hydrological models and even more if trends regarding climate change or land use change are to be considered in management decisions. Evaluating water quality and associated risks still requires conventio-nal lab analyses, both physical-chemical and microbiological. Test kits that allow simple water analyses to be carried out by specifically trained local actors can provide an additional means to acquire water quality data. Remote sensing techniques can be applied for the classification of land use, the detection of land cover changes, and the estimation of soil moisture. They provide a basis for methodological solutions by establishing a land cover change detection approach with deep learning methods on multi-temporal satellite data. A newly developed decision support system based on the WHO Water Safety Plan concept (WSP) enables the recording and evaluation of risks in the catchment area as well as the documentation of measures for risk control. As an online application with Web-GIS geodata processing, it is usa-ble for users without own GIS access. The tool visualizes the results quickly, thereby supporting the communication about the aims of risk analysis and helping to achieve a common understan-ding of which information is relevant. Regarding governance issues and conflict analysis, stakeholder analysis is important to obtain an overview on roles and relations. It allows to develop a participation strategy that identifies whom to involve during what project activity and in what intensity. Repeated field trips and interviews with key actors are required to achieve a full understanding and detailed overview of the of stakeholders’ positions regarding the project’s goals, and of the interrelations between stakeholder groups.The newly developed policy- and conflict analysis allows identifying central (latent) water use related conflicts as well as developing and assessing possible integrated policy-solutions for an improved and sustainable water management. The approach makes diverging goals and policy alternatives of different water user groups explicit. It reveals how non-intended side-effects of policies affect the effectiveness of other policies and allows identifying consistent, synergetic and sustainable policy mixes. For the development of integrated concepts for water supply and sanitation, an inter- and trans-disciplinary process, where scientists, water and sanitation engineers, social scientists as well as local actors and stakeholders collaborate closely, proves to be very helpful. Participatory assess-ment allows identifying the evaluation criteria that are relevant for local stakeholders and taking them into account in the further development of the concepts. Bringing actors from the upper and lower catchment together in joint multi-stakeholder workshops leads to more dialogue and fosters cooperation between catchment parts. Overall, the integrated approach allows to take the social-embeddedness of technological concepts into account and to co-construct concepts together with local stakeholders. Furthermore, involving stakeholders with different perspectives still requires ensuring the same level of information and knowledge. Stakeholders need to be enabled and empowered regularly to participate in the integrated planning processes – to this end, capacity building workshops are valuable. Using SDG 6 as a point of reference assured that our results are linkable to international debates and standards through the comparability of indicators.Central conditions to transfer our integrated approaches include the active interest of stakehol-ders, a continuous and/or repeated collaboration between local actors, researchers and NGOs, as well as sufficient data, a common problem awareness, and comparable boundary conditions (regarding, e.g., hydrology, geochemistry, sociology, culture, education, urban water manage-ment, etc.). Local contexts, however, can be very specific, so the approaches need to be carefully contextualized.

Abstract

Magnetic microparticles functionalized with tailored ZnFeZr oxyhydroxide adsorbent were used for the reversible sorption of orthophosphate and recalcitrant organo-phosphonates from wastewater. The loaded particles were harvested magnetically from water, regenerated in an alkaline solution and reused numerous times. The applicability of the technology to treat brackish water reverse osmosis concentrates was tested under controlled synthetic conditions by investigating the influence of typical metals (Ca2+, Pb2+, Cu2+) on the removal of common phosphonates (HEDP, NTMP, EDTMP), and vice versa. When present at equimolar concentrations, metal cations enhanced the adsorption of phosphonates and were co-adsorbed at pH 4.0–4.5 (with removals of 83–93% for Pb2+ and 53–73% for Cu2+), likely through ternary complex formation. In the absence of metals, at pH > pHPZC ∼7 (the material point of zero charge), a drop in adsorption efficiency was observed for orthophosphate and all phosphonates. Thus, at pH 7, an increased adsorbent dose (>0.1 g/L) was necessary to remove 1 mg/L NTMP-P in 30 min. The reusability and effluent polishing potential of the ZnFeZr particles was demonstrated in a pilot test with municipal wastewater throughout 55 adsorption/desorption cycles without any drop in performance. Consistent removal of the non-reactive phosphorus species to ultra-low concentrations (<0.05 mg/L Ptot) and complete orthophosphate elimination (<0.005 mg/L PO4-P) was maintained under optimal conditions.

Abstract

Sludge water (SW) arising from the dewatering of anaerobic digested sludge causes high back loads of ammonium, leading to high stress (inhibition of the activity of microorganisms by an oversupply of nitrogen compounds (substrate inhibition)) for wastewater treatment plants (WWTP). On the other hand, ammonium is a valuable resource to substitute ammonia from the energy intensive Haber-Bosch process for fertilizer production. Within this work, it was investigated to what extent and under which conditions Carpathian clinoptilolite powder (CCP 20) can be used to remove ammonium from SW and to recover it. Two different SW, originating from municipal WWTPs were investigated (SW1: c0 = 967 mg/L NH4-N, municipal wastewater; SW2: c0 = 718–927 mg/L NH4-N, large industrial wastewater share). The highest loading was achieved at 307 K with 16.1 mg/g (SW1) and 15.3 mg/g (SW2) at 295 K. Kinetic studies with different specific dosages (0.05 gCLI/mgNH4-N), temperatures (283–307 K) and pre-loaded CCP 20 (0–11.4 mg/g) were conducted. At a higher temperature a higher load was achieved. Already after 30 min contact time, regardless of the sludge water, a high load up to 7.15 mg/g at 307 K was reached, achieving equilibrium after 120 min. Pre-loaded sorbent could be further loaded with ammonium when it was recontacted with the SW.

Abstract

Indicators are essential to monitor the progress of the Agenda 2030. An indicator summarizes information and helps policy makers to take important decisions regarding the implementation of measures to achieve the Sustainable Development Goals (SDGs). However, this requires data that is not available in many places. In order to fill this data gap, a transect walk with lo-cal stakeholders can contribute to the collection of additional qualitative data. This instrument was applied in San Andrés de Tupicocha, a village in the Peruvian Andes, in order to collect the necessary and missing data for assessing the situation regarding SDG 6.1 on drinking water and SDG 6.2 on sanitation and hygiene. The analysis of this data revealed a deeper insight into the exciting conditions concerning drinking water and sanitation. The integration of the newly gathered data in the evaluation of SDG 6.1 and 6.2 leads to more realistic results in comparison with the exclusive use of statistic data of the Peruvian national census.

Abstract

Phosphonates are widely used in various industries. It is desirable to remove them before discharging phosphonate-containing wastewater. This study describes a large number of batch experiments with adsorbents that are likely suitable for the removal of phosphonates. For this, adsorption isotherms for four different granular ferric hydroxide (GFH) adsorbents were determined at different pH values in order to identify the best performing material. Additionally, the influence of temperature was studied for this GFH. A maximum loading for nitrilotrimethylphosphonic acid (NTMP) was found to be $\sim$12 mg P/g with an initial concentration of 1 mg/L NTMP-P and a contact time of 7 days at room temperature. Then, the adsorption of six different phosphonates was investigated as a function of pH. It was shown that GFH could be used to remove all investigated phosphonates from water and, with an increasing pH, the adsorption capacity decreased for all six phosphonates. Finally, five adsorption-desorption cycles were carried out to check the suitability of the material for multiple re-use. Even after five cycles, the adsorption process still performed well.

Abstract

Ten times at intervals of 1–2 months, individual treatment stages of two wastewater treatment plants (WWTPs) were analyzed for the five quantitatively most widely used phosphonates. The total dissolved concentration of the investigated phosphonates in the influents was between 131 µg/L and 384 µg/L. The nitrogen-free phosphonates 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC) and 1-hydroxyethylidene(1,1-diphosphonic acid) (HEDP) accounted for an average proportion of 83–85%. Diethylenetriaminepenta(methylene phosphonic acid) (DTPMP) contributed with 13–14%, whereas aminotris(methylphosphonic acid) (ATMP) (≤15 µg/L) and ethylenediaminetetra(methylene phosphonic acid) (EDTMP) (≤11 µg/L) contents detected in the WWTP influents were comparatively low. The application of new analytical methods allowed the quantification of phosphonates in the solid fraction of the WWTP influents for the first time. High loads of phosphonates were determined (223–2555 mg/kg), indicating that 20%–80% of the phosphonates are present in the adsorbed state. The removal of total dissolved phosphonate by secondary clarification was between 69.7% and 92.4% (medians: 90.7% and 87.7%). In both WWTPs, HEDP (medians: 89.2% and 86.4%) was slightly better eliminated than PBTC (medians: 87.2% and 82.5%). In the sand filtration stage of a WWTP, the average removal was not further improved. In contrast, an additional removal of dissolved phosphonates could be achieved by activated carbon treatment (median: 96.4%). The proportion of phosphonate-P in the dissolved unreactive phosphorus fraction was consistently between 10% and 40% throughout all treatment stages.

Abstract

Sediment, suspended matter (SM), and water of a large river (Neckar; River1) and a small river (Körsch; River2) were analyzed for the phosphonates 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC), 1-hydroxyethylidene (1,1-diphosphonic acid) (HEDP), aminotris (methylphosphonic acid) (ATMP), ethylenediaminetetra (methylene phosphonic acid) (EDTMP), and diethylenetriaminepenta (methylene phosphonic acid) (DTPMP). Ten samplings were performed at intervals of one to two months during one year, each covering the relevant matrices before and behind the discharge point of a wastewater treatment plant (WWTP). In River1, the total concentration of dissolved phosphonate did not change significantly (2.4–5.8 µg/L before vs. 2.5–6.6 µg/L behind WWTP; p = 0.9360). In River2, it increased significantly from <0.1–1.6 µg/L to 19–39 µg/L (p < 0.0001). Based on the median, the total phosphonate load in River1 sediment increased 1.9-fold (6.7–29.4 mg/kg before vs. 17.8–53.5 mg/kg behind WWTP; p = 0.0033) and in River2 by a factor of eight (1.8–5.0 mg/kg before vs. 18.1–51.4 mg/kg behind WWTP; p < 0.0001). This indicates that phosphonates discharged by WWTPs adsorb onto solid particles and accumulate in the sediment. In the case of River2, the SM load could reach values of 1000–1710 mg/kg behind the WWTP, presumably due to the introduction of insufficiently retained activated sludge particles of >2000 mg/kg phosphonate loads. In general, the nitrogen-free phosphonates PBTC and HEDP were most predominant in both dissolved and adsorbed form, of which HEDP had the highest adsorption affinity.

Abstract

Phosphonates are increasingly used as water-softening agents in detergents, care products, and industrial processes. Despite poor biodegradability, high removal rates during wastewater treatment (WWT) have been observed, owing to strong adsorption affinity to activated sludge and mineral surfaces. Due to phosphonates representing challenging analytes, no method for the compound-specific quantification of phosphonates from solid samples has hitherto been published. In order to improve the data foundation on the environmental fate of phosphonates, an analytical method based on anion exchange chromatography and detection by electrospray ionization coupled to tandem mass spectrometry (IC-ESI-MS/MS) was developed, allowing the trace quantification of phosphonates from surface water (LOQs between 0.04 and 0.16 $\mu$g/L), wastewater (LOQs between 0.6 and 2.3 $\mu$g/L), sediment and suspended matter of rivers (LOQ <þinspace0.1 mg/kg), and suspended matter of wastewater (LOQ <þinspace1 mg/kg). Specificity and selectivity were enhanced by the implementation of isotope-labeled internal phosphonate standards derived through synthesis. This study describes the development of a comprehensive tool set for the determination of aminotris(methylenephosphonic acid) (ATMP), diethylenetriaminepenta(methylenephosphonic acid) (DTPMP), ethylenediaminetetra(methylenephosphonic acid) (EDTMP), 1-hydroxyethanediphosphonic acid (HEDP), and 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTC) during WWT and in the aqueous environment. In the investigated matrices, HEDP and PBTC were generally present in highest and EDTMP in lowest abundance. The phosphonate contents detected in river water were in the sub to low $\mu$g/L range, depending on the wastewater burden, whereas contents in the low to medium $\mu$g/L range were found in untreated wastewater. The loads of the solid phases exceeded the contents of the corresponding liquid phases by roughly three orders of magnitude. Current data imply that phosphonates undergo significant partitioning to the solid phase during WWT and in natural water bodies.

Abstract

Die optimale Ausnutzung des vorhandenen Speichervolumens im gesamten Abwassernetz ist ein wichtiger Beitrag zum Gewässerschutz. Nicht optimal eingestellte Drosselorgane haben erhebliche Auswirkungen auf die Entlastungsaktivität von Regenüberlaufbecken und somit auf die Belastung der betroffenen Gewässer. Die Optimierung der Drosseleinstellung auf Basis von Niederschlags-Abfluss- und Schmutzfrachtmodellen ist daher ein wesentlicher Arbeitsschritt bei der Erstellung von Regenwasserkonzeptionen. Der vorliegende Beitrag beschreibt eine alternative Methode zur Optimierung der Drosselabflüsse an Regenüberlaufbecken auf der Basis von Messdaten. Die Vorgehensweise wurde an einem einfachen idealisierten Beispielsystem getestet. Dazu wurden Langzeit-Messdaten von zwei realen Regenüberlaufbecken verwendet. Die vorgestellte Methodik zeigt eine gute Anwendbarkeit im fiktiven vereinfachten Einzugsgebiet. Durch die direkte Verwendung der Messdaten können die Unsicherheiten in den Optimierungsergebnissen reduziert werden. Es wurden keine wesentlichen Unterschiede bei der Bestimmung der optimalen Drosselabflüsse für verschiedene Optimierungsziele (Minimierung von Überlaufvolumen, -fracht und Überlaufdauer) festgestellt. Eine Messdatenzeitreihe von vier Monaten mit mindestens 10 Regenereignissen reichte im untersuchten Fall für zuverlässige Optimierungsergebnisse aus. Während Regenwasserkonzeptionen in der Regel auf einen Planungshorizont von etwa 20 Jahren ausgelegt sind, eignet sich die messdatenbasierte Methode für eine regelmäßige Anwendung (z. B. jährlich). Das System kann somit fortwährend an die Entwicklung des Einzugsgebietes angepasst werden. Voraussetzung ist allerdings ist eine sorgfältige Prüfung der Messdaten.

Abstract

Aus verschiedenen Studien liegen Daten zu Konzentrationen von Mik-roschadstoffen in urban geprägten Gewässern vor. Diese stellen jedoch nur mehr oder weniger lange Ausschnitte aus einem dynamischen Gesamtge-schehen dar. Sie lassen keine unmittelbaren Rückschlüsse auf mittlere Kon-zentrationen, Häufigkeit von Grenzwertüberschreitungen oder langfristige Frachtströme zu. In der hier vorgestellten Simulationsstudie wurden am Beispiel eines einfachen idealisierten Einzugsgebiets die Verhältnisse von Regen- und Schmutzwasserabfluss und die Durchmischung mit dem Ba-sisabfluss des Gewässers über einen Zeitraum von 9 Monaten analysiert. Die Ergebnisse machen deutlich, dass sowohl die Überwachung von Grenz-werten im unmittelbar betroffenen Gewässer, als auch die Ermittlung von langfristigen Stofffrachten eine gezielte Berücksichtigung des Regenwetter-abflusses zwingend voraussetzt.

Abstract

The water resources of Lima Metropolitan Area are exposed to considerable pressure as a result of climate change, population growth, overexploitation, and pollution. Ensuring a comprehensive supply of hygienically safe drinking water and sanitation throughout the region poses major challenges. Within the framework of the TRUST project, funded by the German Federal Ministry of Education and Research (BMBF), concepts for safe drinking water supply, sanitation and water reuse are being developed together with local actors and national authorities to contribute to the achievement of the Sustainable Development Goals

Abstract

The water resources of Lima Metropolitan Area are exposed to considerable ressure as a result of climate change, population growth, overexploitation, and pollution. Ensuring a comprehensive supply of hygienically safe drinking water and sanitation throughout the region poses major challenges. Within the framework of the TRUST project, funded by the German Federal Ministry of Education and Research (BMBF), concepts for safe drinking water supply, sanitation and water reuse are being developed together with local actors and national authorities to contribute to the achievement of the Sustainable Development Goals.

Abstract

Rivers and lakes in urbanised areas are increasingly appreciated for their high ecological and recreational value. The demand for bathing sites is growing. However, in many German rivers as the Ruhr River, bathing has been prohibited for decades. At Lake Baldeney, an impounded lake of the Ruhr River, located in a densely populated area in North-Rhine-Westphalia, the first bathing place was opened in 2017. Receiving water from combined sewer overflows during heavy rain events, the hygienic quality of the water body could be affected. Due to that an extensive monitoring programme of quality parameters along the Ruhr River has been carried out during the last years and an early warning system has been established to assure a safe bathing environment at all times in a previous research project. In this article highly resolved precipitation data from six rain gauges, overflow data from four combined sewer overflow (CSO) tanks and one storage sewer as well as flow data from the River Ruhr was analysed together with daily measurements of Escherichia coli (E. coli) and intestinal enterococci (Int. E.) to assess the prediction capacity of hygienic contaminations at the bathing site during three swimming seasons. Data evaluation showed a good predictive capability of precipitation data. Overflow data showed less predictive performance when using overflow information from one tank only, indicating that single overflow events not necessarily lead to hygienic contaminations above critical thresholds.

Abstract

Rivers and lakes in urbanised areas are increasingly appreciated for their high ecological and recreational value. The demand for bathing sites is growing. However, in many German rivers as the Ruhr River, bathing has been prohibited for decades. At Lake Baldeney, an impounded lake of the Ruhr River, located in a densely populated area in North-Rhine-Westphalia, the first bathing place was opened in 2017. Receiving water from combined sewer overflows during heavy rain events, the hygienic quality of the water body could be affected. Due to that an extensive monitoring programme of quality parameters along the Ruhr River has been carried out during the last years and an early warning system has been established to assure a safe bathing environment at all times in a previous research project. In this article highly resolved precipitation data from six rain gauges, overflow data from four combined sewer overflow (CSO) tanks and one storage sewer as well as flow data from the River Ruhr was analysed together with daily measurements of Escherichia coli (E. coli) and intestinal enterococci (Int. E.) to assess the prediction capacity of hygienic contaminations at the bathing site during three swimming seasons. Data evaluation showed a good predictive capability of precipitation data. Overflow data showed less predictive performance when using overflow information from one tank only, indicating that single overflow events not necessarily lead to hygienic contaminations above critical thresholds.

Abstract

Journal of Hydrology, 559 (2018) 442-453. doi:10.1016/j.jhydrol.2018.02.046

Abstract

Feststoffe gelten bereits seit geraumer Zeit als Bewertungskri-terium für die stoffliche Belastung von Regenwetterabflüssen. Mit Einfüh-rung des neuen Regelwerkes DWA-A102/BWK-A 3 sollen diese auf die Fein-fraktion \textless 63 mm (AFS63) eingegrenzt werden. Die labortechnische Bestim-mung dieses Parameters ist jedoch derzeit noch nicht definiert. Ziel dieses Beitrages der Hochschulgruppe Simulation (HSGSim) ist es zunächst, den ak-tuellen Stand der Bestimmung anhand einer Umfrage sowie anhand der Auswertung publizierter Studien aufzuzeigen. Davon ausgehend und erwei-tert durch gezielte Untersuchungen werden erste Vorschläge zur Vorge-hensweise bei der labortechnischen Bestimmung des Parameters gegeben. Am Ende des Beitrags werden Schlussfolgerungen abgeleitet und der wei-tere Handlungsbedarf sowie das weitere Vorgehen der HSGSim aufgezeigt.