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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, Thomas01A - Beitrag in wissenschaftlicher ZeitschriftPublikation 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, ThomasOzonation 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 ZeitschriftPublikation 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, SandraWastewater-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 ZeitschriftPublikation 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, ThomasWe 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 ZeitschriftPublikation Phosphorus recovery in an acidic environment using layer-by-layer modified membranes(Elsevier, 15.07.2019) Remmen, Kirsten; Müller, Barbara; Köser, Joachim; Wintgens, ThomasPhosphorus (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 ZeitschriftPublikation Anaerobic digestion of biowastes in India: Opportunities, challenges and research needs(Elsevier, 15.04.2019) Breitenmoser, Lena; Gross, Thomas; Huesch, Ragini; Rau, Julius; Hugi, Christoph; Wintgens, ThomasThe quest for improved living conditions in rapidly growing Indian communities puts pressure on natural resources and produces emissions which harm the environment, society and the economy. Current municipal solid waste (MSW) practices are an important example, as most waste remains untreated and is often deposited on unsafe dumpsites or burned on open fires. Anaerobic digestion (AD) is an option to treat the large biodegradable fraction ('biowaste'). In rural parts of India, the technology to supply energy from biogas has been promoted for 30 years. Biowaste treatment in urban MSW management and organic fertilizer ('digestate') production for agriculture via AD have more recently gained attention but with limited success so far. Recent environmental policies in waste, energy, agricultural and other sectors have, however, set important cornerstones for a broader diffusion in the coming years. On the basis of peer-reviewed literature and governmental reports, we identify barriers and enabling factors along the AD chain (biowaste to technology to product utilization), and analyse relevant boundary conditions for the new multi-sector policies. We show that AD implementation has repeatedly failed due to unrealistic assumptions on biowaste quantity and quality, underestimation of the complex biowaste supply chain, unsuitable AD designs and overestimation of economic returns from biogas and digestate. Local knowledge and capacities for planning and process control are lacking in many places and resources required for operation and maintenance in the long run have often been ignored. We found that the multi-facetted value propositions of AD - including biowaste treatment, energy and fertilizer products - have only been partially tapped due to the exclusive focus on biogas. The new sector policies provide important enabling factors for change. Decentralized AD plants operating on a few tons biowaste per day from reliable and manageable sources (e.g. fruit and vegetable markets) could be a more promising step forward than large-scale investments which rely on large biowaste volumes from various sources. The parallel development of biowaste management, planning tools for municipalities, standardized digestate monitoring protocols and studies on simple, low-cost optimization measures for methane recovery from a wide range of biowastes and innovative high-solid AD digester designs will be prerequisites for the long-term future of AD projects.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Poseidon—Decision Support Tool for Water Reuse(Elsevier, 2019) Oertlé, Emmanuel; Hugi, Christoph; Wintgens, Thomas01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Layer-by-layer membrane modification allows scandium recovery by nanofiltration(Royal Society of Chemistry, 07/2019) Remmen, Kirsten; Lenz, Markus; Hedwig, Sebastian; Wintgens, ThomasAluminium 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 ZeitschriftPublikation Comparison of methods to assess the integrity and separation efficiency of ultrafiltration membranes in wastewater reclamation processes(Elsevier, 06/2018) Krahnstöver, Thérèse; Hochstrat, Rita; Wintgens, ThomasMembrane filtration is used in many water reuse applications, thanks to its high separation efficiency with regard to particles, bacteria, cysts and in the case of ultrafiltration even viruses. However, the separation performance of a membrane system can be affected and the permeate quality can be reduced or increased by phenomena such as membrane damage, membrane fouling or microbiological regrowth on both permeate and retentate side of the membrane. Thus, in order to guarantee a sufficiently high permeate quality, the separation efficiency of a membrane system has to be assessed sensitively, reliably and, if possible, continuously. In the here presented study, a variety of different analytical methods was tested to assess the separation efficiency of ultrafiltration membranes in a pilot-scale wastewater reclamation system. After intentionally damaging the membrane to different degrees, its integrity was monitored by pressure decay testing and permeate turbidity measurements, and by continuously monitoring the concentration of micro- and nanoparticles in the permeate stream. The microbiological permeate quality was not only assessed by plate counting, but also by flow cytometric measurements. The results showed that the membrane integrity is primarily affected by physical damaging, as detectable by pressure decay testing, while the permeate quality strongly depends on particle-membrane interactions such as formation of a fouling layer or clogging of membrane defects. Nanoparticle counting was found to be a very sensitive method to continuously monitor the membrane’s separation efficiency. Additionally, flow cytometry revealed that bacterial regrowth on the permeate side can affect the microbiological permeate quality in particular.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation UV/H2O2 before biological treatment in drinking water: effects on the removal of micropollutants and biodegradability(09/2018) Wünsch, Robin; Cayon, David; Eugster, Fabienne; Plattner, Julia; Gebhardt, Jens; Wülser, Richard; von Gunten, Urs; Wintgens, Thomas06 - Präsentation