Wintgens, Thomas

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Wintgens, Thomas

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  • Kein Vorschaubild vorhanden
    Publikation
    Microbial communities and processes in biofilters for post-treatment of ozonated wastewater treatment plant effluent
    (Elsevier, 15.01.2023) Sauter, Daniel; Steuer, Andrea; Wasmund, Kenneth; Hausmann, Bela; Szewzyk, Ulrich; Sperlich, Alexander; Gnirss, Regina; Cooper, Myriel; Wintgens, Thomas
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Vorschaubild
    Publikation
    Tradeoff between micropollutant abatement and bromate formation during ozonation of concentrates from nanofiltration and reverse osmosis processes
    (Elsevier, 2022) Wünsch, Robin; Hettich, Timm; Prahtel, Marlies; Thomann, Michael; Wintgens, Thomas; Von Gunten, Urs
    Water treatment with nanofiltration (NF) or reverse osmosis (RO) membranes results in a purified permeate and a retentate, where solutes are concentrated and have to be properly managed and discharged. To date, little is known on how the selection of a semi-permeable dense membrane impacts the dissolved organic matter in the concentrate and what the consequences are for micropollutant (MP) abatement and bromate formation during concentrate treatment with ozone. Laboratory ozonation experiments were performed with standardized concentrates produced by three membranes (two NFs and one low-pressure reverse osmosis (LPRO) membrane) from three water sources (two river waters and one lake water). The concentrates were standardized by adjustment of pH and concentrations of dissolved organic carbon, total inorganic carbon, selected micropollutants (MP) with a low to high ozone reactivity and bromide to exclude factors which are known to impact ozonation. NF membranes had a lower retention of bromide and MPs than the LPRO membrane, and if the permeate quality of the NF membrane meets the requirements, the selection of this membrane type is beneficial due to the lower bromate formation risks upon concentrate ozonation. The bromate formation was typically higher in standardized concentrates of LPRO than of NF membranes, but the tradeoff between MP abatement and bromate formation upon ozonation of the standardized concentrates was not affected by the membrane type. Furthermore, there was no difference for the different source waters. Overall, ozonation of concentrates is only feasible for abatement of MPs with a high to moderate ozone reactivity with limited bromate formation. Differences in the DOM composition between NF and LPRO membrane concentrates are less relevant than retention of MPs and bromide by the membrane and the required ozone dose to meet a treatment target.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Vorschaubild
    Publikation
    Anaerobic digestion of biowaste in Indian municipalities. Effects on energy, fertilizers, water and the local environment
    (Elsevier, 07/2021) Gross, Thomas; Breitenmoser, Lena; Hugi, Christoph; Wintgens, Thomas
    Anaerobic digestion (AD) of biowaste seems promising to provide renewable energy (biogas) and organic fertilizers (digestate) and mitigate environmental pollution in India. Intersectoral analyses of biowaste management in municipalities are needed to reveal benefits and trade-offs of AD at the implementation-level. Therefore, we applied material flow analyses (MFAs) to quantify effects of potential AD treatment of biowaste on energy and fertilizer supply, water consumption and environmental pollution in two villages, two towns and two cities in Maharashtra. Results show that in villages AD of available manure and crop residues can cover over half of the energy consumption for cooking (EC) and reduce firewood dependency. In towns and cities, AD of municipal biowaste is more relevant for organic fertilizer supply and pollution control because digestate can provide up to several times the nutrient requirements for crop production, but can harm ecosystems when discharged to the environment. Hence, in addition to energy from municipal biowaste - which can supply 4-6% of EC - digestate valorisation seems vital but requires appropriate post-treatment, quality control and trust building with farmers. To minimize trade-offs, water-saving options should be considered because 2-20% of current groundwater abstraction in municipalities is required to treat all available biowaste with 'wet' AD systems compared to <3% with 'dry' AD systems. We conclude that biowaste management with AD requires contextualized solutions in the setting of energy, fertilizers and water at the implementation-level to conceive valorization strategies for all AD products, reduce environmental pollution and minimize trade-offs with water resources.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Vorschaubild
    Publikation
    Micropollutants as internal probe compounds to assess UV fluence and hydroxyl radical exposure in UV/H2O2 treatment
    (Elsevier, 18.02.2021) Wünsch, Robin; Mayer, Carina; Plattner, Julia; Eugster, Fabienne; Wülser, Richard; Gebhardt, Jens; Hübner, Uwe; Canonica, Silvio; von Gunten, Urs; Wintgens, Thomas
    Organic micropollutants (MPs) are increasingly detected in water resources, which can be a concern for human health and the aquatic environment. Ultraviolet (UV) radiation based advanced oxidation pro- cesses (AOP) such as low-pressure mercury vapor arc lamp UV/H2O2 can be applied to abate these MPs. During UV/H2O2 treatment, MPs are abated primarily by photolysis and reactions with hydroxyl radicals (•OH), which are produced in situ from H2O2 photolysis. Here, a model is presented that calculates the applied UV fluence (Hcalc) and the •OH exposure (CT•OH,calc) from the abatement of two selected MPs, which act as internal probe compounds. Quantification of the UV fluence and hydroxyl radical exposure was generally accurate when a UV susceptible and a UV resistant probe compound were selected, and both were abated at least by 50 %, e.g., iopamidol and 5-methyl-1H-benzotriazole. Based on these key parameters a model was developed to predict the abatement of other MPs. The prediction of abatement was verified in various waters (sand filtrates of rivers Rhine and Wiese, and a tertiary wastewater efflu- ent) and at different scales (laboratory experiments, pilot plant). The accuracy to predict the abatement of other MPs was typically within ±20 % of the respective measured abatement. The model was further as- sessed for its ability to estimate unknown rate constants for direct photolysis (kUV,MP) and reactions with •OH (k•OH,MP). In most cases, the estimated rate constants agreed well with published values, considering the uncertainty of kinetic data determined in laboratory experiments. A sensitivity analysis revealed that in typical water treatment applications, the precision of kinetic parameters (kUV,MP for UV susceptible and k•OH,MP for UV resistant probe compounds) have the strongest impact on the model’s accuracy
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Kein Vorschaubild vorhanden
    Publikation
    Detection of SARS-CoV-2 in raw and treated wastewater in Germany – Suitability for COVID-19 surveillance and potential transmission risks
    (Elsevier, 10.01.2021) Westhaus, Sandra; Weber, Frank-Andreas; Schiwy, Sabrina; Linnemann, Volker; Brinkmann, Markus; Widera, Marek; Greve, Carola; Janke, Axel; Hollert, Henner; Wintgens, Thomas; Ciesek, Sandra
    Wastewater-based monitoring of the spread of the new SARS-CoV-2 virus, also referred to as wastewater-based epidemiology (WBE), has been suggested as a tool to support epidemiology. An extensive sampling campaign, including nine municipal wastewater treatment plants, has been conducted in different cities of the Federal State of North Rhine-Westphalia (Germany) on the same day in April 2020, close to the first peak of the corona crisis. Samples were processed and analysed for a set of SARS-CoV-2-specific genes, as well as pan-genotypic gene sequences also covering other coronavirus types, using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Additionally, a comprehensive set of chemical reference parameters and bioindicators was analysed to characterize the wastewater quality and composition. Results of the RT-qPCR based gene analysis indicate the presence of SARS-CoV-2 genetic traces in different raw wastewaters. Furthermore, selected samples have been sequenced using Sanger technology to confirm the specificity of the RT-qPCR and the origin of the coronavirus. A comparison of the particle-bound and the dissolved portion of SARS-CoV-2 virus genes shows that quantifications must not neglect the solid-phase reservoir. The infectivity of the raw wastewater has also been assessed by viral outgrowth assay with a potential SARS-CoV-2 host cell line in vitro, which were not infected when exposed to the samples. This first evidence suggests that wastewater might be no major route for transmission to humans. Our findings draw attention to the need for further methodological and molecular assay validation for enveloped viruses in wastewater.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Vorschaubild
    Publikation
    Deep-bed filters as post-treatment for ozonation in tertiary municipal wastewater treatment. Impact of design and operation on treatment goals
    (Royal Society of Chemistry, 2021) Wintgens, Thomas; Sauter, Daniel; Dabrowska, Agata; Bloch, Robert; Stapf, Michael; Miehe, Ulf; Sperlich, Alexander; Gnirss, Regina
    Ozonation followed by biological post-treatment is an established technology for abatement of organic micropollutants (OMP) from municipal wastewater. Although the necessity of biological post-treatment for oxidation by-product (OBP) removal is widely accepted, there is still discussion about the appropriate design and operation. The presented pilot-study investigates the impact of filter material and contact time on the removal efficiency of bulk organics, OMP, and OBP in three different deep-bed filters operated in parallel as post-treatment after ozonation (biological activated carbon (BAC) filter, dual-media filter sand/BAC and dual-media filter sand/anthracite). The use of BAC instead of non-adsorptive filter material resulted in higher removal of DOC and dissolved oxygen which indicates increased biological activity. Moreover, both BAC containing filters showed additional removal for a number of OMP even at high treated bed volumes of >50 000 whereas no removal was observed in the sand/anthracite filter. Analysis of N-nitrosodimethylamine (NDMA) and several carbonyl compounds revealed a clear formation of these biodegradable OBP during ozonation. A strong correlation was found between carbonyl formation and the specific ozone dose. Removal of OBP in the sand/BAC and the sand/anthracite filter was tested at different empty bed contact times (EBCT). While NDMA was efficiently removed independent of EBCT changes, there was a slightly negative impact of shorter EBCT on the reduction of carbonyl compounds. Furthermore, it was demonstrated that the integration of enhanced phosphorus removal into post-treatment is feasible with relatively low efforts by inline coagulant dosing (FeCl3) in the filter influent.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Kein Vorschaubild vorhanden
    Publikation
    Impact of ozonation and biological post. Treatment of municipal wastewater on microbiological quality parameters
    (Royal Society of Chemistry, 2021) Sauter, Daniel; Stange, Claudia; Schumacher, Vera; Tiehm, Andreas; Gnirrs, Regina; Wintgens, Thomas
    Ozonation is an established process for advanced wastewater treatment, with a dose-dependent degree of disinfection. It is generally followed by biological post-treatment with the main objective of oxidation by- product abatement. However, there is little research on the impact of the combination of ozonation and biological post-treatment on microbiological quality parameters. This long-term study investigated pilot- scale ozonation with six different filtration processes (4 deep-bed filter systems and 2 vertical flow constructed wetlands) as biological post-treatment. A broad spectrum of microbial parameters has been monitored for a comprehensive evaluation of the disinfection performance. While vegetative bacteria (Escherichia coli and enterococci) were inactivated to a large extent by ozone, spore-forming Clostridium perfringens and viral indicator somatic coliphages exhibited a high ozone tolerance and could only be effectively retained in subsequent filtration steps. Extended hydraulic retention times as well as fine filter materials in post-treatment proved to be beneficial for faecal indicator abatement. In deep-bed filters, coagulant dosing was an additional important factor for the disinfection performance. Post-treatment also played a crucial role in the reduction of the antibiotic resistance gene sul1 and the indicator genes intl1 (mobile genetic element) and 16S rRNA (total bacterial number), whereas inactivation of antibiotic resistant bacteria was dominated by the ozonation process. In summary, the combined disinfection mechanisms of ozonation (chemical) and filtration (physical) resulted in an effective abatement of a wider range of microbial parameters than the individual processes. Regrowth during post-treatment has only been observed for the parameters intact cell counts and Pseudomonas aeruginosa with mean concentration increases of 0.5–1 log units.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Kein Vorschaubild vorhanden
    Publikation
    Improved phosphoric acid recovery from sewage sludge ash using layer-by-layer modified membranes
    (Elsevier, 01.10.2019) Paltrinieri, Laura; Remmen, Kirsten; Müller, Barbara; Köser, Joachim; Wintgens, Thomas
    We report an advanced treatment method for phosphoric acid recovery from leached sewage sludge ash. Layer-by-layer (LbL) polyelectrolyte deposition has been used as a tool to modify and convert a hollow ultrafiltration membrane into a nanofiltration (NF) LbL membrane for H3PO4 recovery. To build the LbL membrane, poly(styrenesulfonate) PSS was chosen as polyanion, while three different polycations were used: a permanently charged polyelectrolyte, poly(diallyldimethylammonium chloride), PDADMAC; a pH-dependent charged polyelectrolyte poly(allylamine hydrochloride), PAH; and a PAH modified with guanidinium groups (PAH-Gu). Based on detailed surface characterizations (AFM, XPS and Zeta-potential) it was concluded that both charge density and pH-responsiveness of the polycations are key parameters to control the final membrane surface structure and transport properties. The surface properties of LbL-coated membranes were correlated with the membrane filtration performance, when exposed to the real leached sewage sludge ash solution. The highest permeability was recorded for (PDADMAC/PSS)6, a result that was rationalized on its loose, and possibly less interpenetrated, structure, followed by (PAH-Gu/PSS)6 characterized by a more dense, compact layer. H3PO4 recovery was the highest in the case of (PDADMAC/PSS)6, but the retention of multivalent metals (Fe3+ and Mg2+) was low, leading to a more contaminated permeate. The opposite trend was observed for (PAH-Gu/PSS)6, resulting in a less metal-contaminated, but also a less H3PO4-concentrated permeate. Our LbL-modified membranes were found to improve the permeability and H3PO4 recovery compared to a commercially available acid-resistant NF membrane.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Kein Vorschaubild vorhanden
    Publikation
    Phosphorus recovery in an acidic environment using layer-by-layer modified membranes
    (Elsevier, 15.07.2019) Remmen, Kirsten; Müller, Barbara; Köser, Joachim; Wintgens, Thomas
    Phosphorus (P) is a limited natural resource and essential for global food supply, particularly given our ever-growing world population. However, natural P deposits are restricted to just a few countries and the quality of exploited primary sources is declining. Phosphorus recovery from sewage sludge or sewage sludge ash leached by acids is hence gaining importance. During P recovery the removal of impurities is a challenge that can be addressed by nanofiltration retaining e. g. multivalent metals and allowing phosphoric acid to pass. However, currently available membranes show low permeability and limit this process option economically. Layer-by-layer (LbL) membrane synthesis is a technology that allows membrane performance to be tailored to individual filtration tasks. Little is known for such membranes with respect to acid resistance, acid permeability and impurity rejection. We show that LBL membranes based on PDADMAC/PSS show the desired passage of phosphoric acid with retentions values below 10%, aluminum retention was always above 95%. Permeabilities up to 4 L/(m2 h bar) were reached even up to a phosphorous recovery of 75%. Overall permeabilities were 16 times higher than a commercial benchmark membrane. Initial stability tests and upscaling into a larger module show the viability of the proposed modification approach.
    01A - Beitrag in wissenschaftlicher Zeitschrift
  • Kein Vorschaubild vorhanden
    Publikation
    Layer-by-layer membrane modification allows scandium recovery by nanofiltration
    (Royal Society of Chemistry, 07/2019) Remmen, Kirsten; Lenz, Markus; Hedwig, Sebastian; Wintgens, Thomas
    Aluminium scandium (Sc) alloys are stronger, more corrosion resistant and more heat tolerant than classical aluminium alloys and allow for 3D printing. In particular, the aerospace industry benefits from better fuel efficiency due to lighter materials as well as the advantages of additive manufacturing. However, Sc is currently not available in sufficient quantities and has recently been identified as a raw material critical to the economy. Due to the recentness of the demand, technologies for recovery of Sc from secondary sources are in their infancy. In this study, Sc recovery from titanium dioxide pigment production waste by nanofiltration was investigated. Custom-made layer-by-layer (LbL) modified membranes were optimized with regards to their elemental retention (i.e., selectivity towards Sc) as well as their acid resistance. In model solutions, the optimized membrane retained up to 64% ± 4% Sc, removing the major impurity, iron (Fe), efficiently (12% ± 7% retention) while achieving high flux [32 L m−2 h−1] at a low transmembrane pressure of 5 bar. Acid resistance was shown down to a pH of 0.1, which could be even further increased (up to ≤3 M HCl) by adding more bi-layers and changing the coating conditions. In real wastes, the optimized LbL membrane showed higher Sc retention (60% vs. 50%) compared to a commercial acid resistant membrane, while achieving considerably higher fluxes [27 L m−2 h−1 versus 1 L m−2 h−1, respectively at 5 bar]. It was possible to operate filtration at low transmembrane pressure with up to 70% permeate recovery and flux that was still high [∼10 L m−2 h−1]. In a nutshell, titanium dioxide pigment wastes contained sufficient amounts to satisfy the growing demand for Sc and can be exploited to their full extent by LbL nanofiltration due to the proven advantages of acid stability, Sc retention and selectivity and high achievable fluxes at low pressures.
    01A - Beitrag in wissenschaftlicher Zeitschrift