Wintgens, Thomas
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Microbial communities and processes in biofilters for post-treatment of ozonated wastewater treatment plant effluent
2023-01-15, Sauter, Daniel, Steuer, Andrea, Wasmund, Kenneth, Hausmann, Bela, Szewzyk, Ulrich, Sperlich, Alexander, Gnirss, Regina, Cooper, Myriel, Wintgens, Thomas
Detection of SARS-CoV-2 in raw and treated wastewater in Germany – Suitability for COVID-19 surveillance and potential transmission risks
2021-01-10, 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.
Tradeoff between micropollutant abatement and bromate formation during ozonation of concentrates from nanofiltration and reverse osmosis processes
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.
Impact of ozonation and biological post. Treatment of municipal wastewater on microbiological quality parameters
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.
Anaerobic digestion of biowaste in Indian municipalities. Effects on energy, fertilizers, water and the local environment
2021-07, 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.