Universität Stuttgart
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Item Open Access Batch studies of phosphonate and phosphate adsorption on granular ferric hydroxide (GFH) with membrane concentrate and its synthetic replicas(2020) Reinhardt, Tobias; Veizaga Campero, Adriana Noelia; Minke, Ralf; Schönberger, Harald; Rott, EduardPhosphonates are widely used as antiscalants for softening processes in drinking water treatment. To prevent eutrophication and accumulation in the sediment, it is desirable to remove them from the membrane concentrate before they are discharged into receiving water bodies. This study describes batch experiments with synthetic solutions and real membrane concentrate, both in the presence of and absence of granular ferric hydroxide (GFH), to better understand the influence of ions on phosphonate and phosphate adsorption. To this end, experiments were conducted with six different phosphonates, using different molar Ca:phosphonate ratios. The calcium already contained in the GFH plays an essential role in the elimination process, as it can be re-dissolved, and, therefore, increase the molar Ca:phosphonate ratio. (Hydrogen-)carbonate ions had a competitive effect on the adsorption of phosphonates and phosphate, whereas the influence of sulfate and nitrate ions was negligible. Up to pH 8, the presence of CaII had a positive effect on adsorption, probably due to the formation of ternary complexes. At pH > 8, increased removal was observed, with either direct precipitation of Ca:phosphonate complexes or the presence of inorganic precipitates of calcium, magnesium, and phosphate serving as adsorbents for the phosphorus compounds. In addition, the presence of (hydrogen-)carbonate ions resulted in precipitation of CaCO3 and/or dolomite, which also acted as adsorbents for the phosphorus compounds.Item Open Access Impact of combined sewer systems on the quality of urban streams : frequency and duration of elevated micropollutant concentrations(2020) Dittmer, Ulrich; Bachmann-Machnik, Anna; Launay, Marie A.Water quality in urban streams is highly influenced by emissions from WWTP and from sewer systems particularly by overflows from combined systems. During storm events, this causes random fluctuations in discharge and pollutant concentrations over a wide range. The aim of this study is an appraisal of the environmental impact of micropollutant loads emitted from combined sewer systems. For this purpose, high-resolution time series of river concentrations were generated by combining a detailed calibrated model of a sewer system with measured discharge of a small natural river to a virtual urban catchment. This river base flow represents the remains of the natural hydrological system in the urban catchment. River concentrations downstream of the outlets are simulated based on mixing ratios of base flow, WWTP effluent, and CSO discharge. The results show that the standard method of time proportional sampling of rivers does not capture the risk of critical stress on aquatic organisms. The ratio between average and peak concentrations and the duration of elevated concentrations strongly depends on the source and the properties of the particular substance. The design of sampling campaigns and evaluation of data should consider these characteristics and account for their effects.Item Open Access Metabolism of 2-chloro-4-methylphenoxyacetate by Alcaligenes eutrophus JMP 134(1993) Pieper, Dietmar Helmut; Stadler-Fritzsche, Karin; Engesser, Karl-Heinrich; Knackmuss, Hans-Joachim2-Chloro-4-methylphenoxyacetate is not a growth substrate for Alcaligenes eutrophus JMP 134 and JMP 1341. It is, however, being transformed by enzymes of 2,4-dichlorophenoxyacetic acid metabolism to 2-chloro-4-methyl-cis, cis-muconate, which is converted by enzymatic 1,4-cycloisomerization to 4-carboxymethyl-2-chloro-4-methylmuconolactone as a dead end metabolite. Chemically, only 3,6-cycloisomerization occurs, giving rise to both diastereomers of 4-carboxychloromethyl-3-methylbut-2-en-4-olide. Those lactones harbonring a chlorosubstituent on the 4-carboxymethyl side chain were surprisingly stable under physiological as well as acidic conditions.Item Open Access Detoxification of pesticide-containing wastewater with FeIII, activated carbon and Fenton reagent and its control using three standardized bacterial inhibition tests(2017) Rott, Eduard; Pittmann, Timo; Wasielewski, Stephan; Kugele, Amélie; Minke, RalfDischarge of toxic industrial wastewaters into biological wastewater treatment plants may result in inhibition of activated sludge bacteria (ASB). In order to find an appropriate method of detoxification, the wastewater of a pesticide-processing plant in Vietnam was treated with three different methods (FeIII, powdered activated carbon (PAC), Fenton (FeII/H2O2)) analyzing the detoxification effect with the nitrification inhibition test (NIT), respiration inhibition test (RIT) and luminescent bacteria test (LBT). The heterotrophic ASB were much more resistant to the wastewater than the autotrophic nitrificants. The NIT turned out to be more suitable than the RIT since the NIT was less time-consuming and more reliable. In addition, the marine Aliivibrio fischeri were more sensitive than the nitrificants indicating that a lack of inhibition in the very practical and time-efficient LBT correlates with a lack of nitrification inhibition. With 95%, the Fenton method showed the highest efficiency regarding the chemical oxygen demand (COD) removal. Although similar COD removal (60–65%) was found for both the FeIII and the PAC method, the inhibitory effect of the wastewater was reduced much more strongly with PAC. Both the NIT and the LBT showed that the PAC and Fenton methods led to a similar reduction in the inhibitory effect.Item Open Access Influence of ammonium ions, organic load and flow rate on the UV/chlorine AOP applied to effluent of a wastewater treatment plant at pilot scale(2018) Rott, Eduard; Kuch, Bertram; Lange, Claudia; Richter, Philipp; Minke, RalfThis work investigates the influence of ammonium ions and the organic load (chemical oxygen demand (COD)) on the UV/chlorine AOP regarding the maintenance of free available chlorine (FAC) and elimination of 16 emerging contaminants (ECs) from wastewater treatment plant effluent (WWTE) at pilot scale (UV chamber at 0.4 kW). COD inhibited the FAC maintenance in the UV chamber influent at a ratio of 0.16 mg FAC per mg COD (kHOCl–COD = 182 M−1s−1). An increase in ammonium ion concentration led to a stoichiometric decrease of the FAC concentration in the UV chamber influent. Especially in cold seasons due to insufficient nitrification, the ammonium ion concentration in WWTE can become so high that it becomes impossible to achieve sufficiently high FAC concentrations in the UV chamber influent. For all ECs, the elimination effect by the UV/combined Cl2 AOP (UV/CC) was not significantly higher than that by sole UV treatment. Accordingly, the UV/chlorine AOP is very sensitive and loses its effectiveness drastically as soon as there is no FAC but only CC in the UV chamber influent. Therefore, within the electrical energy consumption range tested (0.13–1 kWh/m3), a stable EC elimination performance of the UV/chlorine AOP cannot be maintained throughout the year.Item Open Access Neue Ansätze zur Umgestaltung der Hausmüllentsorgung(2006) Kranert, Martin; Fischer, Klaus; Hafner, Georg; Escalante Mora, NicolásDie Hausmüllentsorgung soll in der Zukunft einfacher und kostengünstiger werden. Die bestehenden hohen Umweltstandards sollen beibehalten, die Nutzung von Wertstoffen optimiert werden. Am Lehrstuhl für Abfallwirtschaft und Abluft des Instituts für Siedlungswasserbau, Wassergüte- und Abfallwirtschaft wurde im Jahr 2006 ein Forschungsprojekt abgeschlossen, in dem neue konzeptionelle Ansätze für Baden-Württemberg untersucht wurden. Ziel des Forschungsprojektes war die Erarbeitung von Empfehlungen für eine nachhaltige Abfallwirtschaft. Hierbei sollten einerseits die bestehenden Umweltstandards aufrecht erhalten und andererseits eine Vereinfachung der Abfallwirtschaft insbesondere für die Haushalte erreicht werden.Item Open Access Dosage concentration and pulsing frequency affect the degradation efficiency in simulated bacterial polycyclic aromatic hydrocarbon-degrading cultures(2023) Vogel, Anjela L.; Thompson, Katharine J.; Kleindienst, Sara; Zarfl, ChristianeA major source of anthropogenic polycyclic aromatic hydrocarbon (PAH) inputs into marine environments are diffuse emissions which result in low PAH concentrations in the ocean water, posing a potential threat for the affected ecosystems. However, the remediation of low-dosage PAH contaminations through microbial processes remains largely unknown. Here, we developed a process-based numerical model to simulate batch cultures receiving repeated low-dosage naphthalene pulses compared to the conventionally used one-time high-dosage. Pulsing frequency as well as dosage concentration had a large impact on the degradation efficiency. After 10 days, 99.7%, 97.2%, 86.6%, or 83.5% of the 145 mg L −1 naphthalene was degraded when given as a one-time high-dosage or in 2, 5, or 10 repeated low-concentration dosages equally spaced throughout the experiment, respectively. If the simulation was altered, giving the system that received 10 pulses time to recover to 99.7%, pulsing patterns affected the degradation of naphthalene. When pulsing 10 days at once per day, naphthalene accumulated following each pulse and if the degradation was allowed to continue until the recovered state was reached, the incubation time was prolonged to 17 days with a generation time of 3.81 days. If a full recovery was conditional before the next pulse was added, the scenario elongated to 55 days and generation time increased to 14.15 days. This indicates that dissolution kinetics dominate biodegradation kinetics, and the biomass concentration of PAH-degrading bacteria alone is not a sufficient indicator for quantifying active biodegradation. Applying those findings to the environment, a one-time input of a high dosage is potentially degraded faster than repeated low-dosage PAH pollution and repeated low-dosage input could lead to PAH accumulation in vulnerable pristine environments. Further research on the overlooked field of chronic low-dosage PAH contamination is necessary.Item Open Access Enhanced composting as a way to a climate-friendly management of coffee by-products(2020) San Martin Ruiz, Macarena; Reiser, Martin; Kranert, MartinThis study investigated the performance of aerobic windrow systems by using coffee by-products and green waste to reduce gaseous emissions. Thereafter, a comparison with the current treatment and gaseous emissions at a Coffee Mill in Costa Rica was made. Two different studies where performed in Germany (pile I and II) and one study in a Coffee Mill in Costa Rica (pile III). Temperature, water content, and pH were the key parameters controlled over 35 days in all the systems. Moreover, CH4 emission rates were quantified by a FTIR and by a portable gas detector device where the emissions reached values 100 times higher when coffee by-products as a unique material for the composting process was used. Results show that highest emission rates during the composting process for pile I was 0.007 g(m2)-1 h-1, for pile II 0.006 g(m2)-1 h-1, and for pile III 3.1 g(m2)-1 h-1. It was found that CH4 emissions could be avoided if the mixture and the formation of the windrow piles were performed following the key parameter for composting, and the usage of additional material is used. With this, the reduction of CH4 emissions at the Mill in Costa Rica could be achieved in the future.Item Open Access Food waste generation in Germany in the scope of European legal requirements for monitoring and reporting(2021) Leverenz, Dominik; Schneider, Felicitas; Schmidt, Thomas; Hafner, Gerold; Nevárez, Zuemmy; Kranert, MartinThe European Commission and the German government are committed to the United Nations SDG target 12.3 of reducing food waste along production chains and halving it at retail and consumer levels by 2030. European member states are required to monitor national food waste levels and report annual progress to the European Commission from 2020 onward. In this regard, the main objective of our study is to provide food waste quantities for Germany by applying methods meeting the legal requirements for monitoring and reporting within Europe-wide harmonized methodology. Our results refer to 2015 and are based on the best available data, using a combination of official statistics, surveys, and literature. We found that approx. 11.9 ± 2.4 million tonnes (144 ± 28 kg/(cap·year)) of food waste were generated in Germany, while the reduction potentials varied throughout the different sectors. Even though the underlying data show uncertainties, the outcome of the study represents a starting point for the upcoming monitoring activities in Germany by uncovering data and knowledge gaps. To meet the political reduction targets, a national food waste strategy was launched in 2019 by the German Federal Ministry of Food and Agriculture, which is an important step toward cooperation and exchange between actors along the entire food chain, raising awareness, and improving data quality, monitoring, and implementation of prevention measures in practice.Item Open Access Emission von Pilzsporen in Müllverarbeitungsanlagen(1994) Göttlich, Elke; Engesser, Karl-Heinrich; Bardtke, DieterDie Häufigkeit und Sporendichte verschiedener Pilzarten in der Luft von Kompostwerken, bei der Sortierung, Müllverbrennung und auf Deponien wurden in einer Studie in 11 Betrieben untersucht. Außer A. fumigatus, über dessen klinische und allergologische Bedeutung die meisten Kenntnisse vorliegen, wurden verschiedene Pilzarten, die als potentiell gesundheitlich relevant angesehen werden,in Keimdichten über den derzeitigen Orientierungswerten für Pilzbelastungen der Luft nachgewiesen. Obwohl vergleichbare Daten zumeist fehlen und daher gesicherte Richtgrenzwerte gegenwärtig nicht festgelegt werden können, sind die gesundheitlichen Risiken der Beschäftigten an den Arbeitsplätzen als erheblich anzusehen.