Microbial degradation represents the key process for pollutant elimination in groundwater and soi... more Microbial degradation represents the key process for pollutant elimination in groundwater and soil. A careful and site-specific evaluation and monitoring is a prerequisite for the responsible application of the intrinsic bioremediation (natural attenuation) concept. In this paper, a case study focussing on tar oil pollutants is presented. Intrinsic biodegradation of PAH, BTEX, and heterocyclic aromatics was demonstrated by analysis of pollutant profiles, groundwater hydrochemistry, composition of the microflora, and microcosm studies. Aerobic as well as anaerobic processes in the presence of nitrate, Fe(lll), or sulfate, contributed to microbial pollutant elimination.
Heterocyclic hydrocarbons (NSO-HET) containing nitrogen (N), sulphur (S) or oxygen (O) atoms are ... more Heterocyclic hydrocarbons (NSO-HET) containing nitrogen (N), sulphur (S) or oxygen (O) atoms are constitutes of tar oil, commonly found downstream of former gasworks sites (Zamfirescu & Grathwohl, 2001, Piepenbrink et al. 2005). Typical NSO-HET ́s are benzofuran, methyl-benzofurans, methylquinolines, acridine or carbazole. Different field studies indicate that most NSO-HET are highly mobile due to their high water solubility. The low anaerobic biodegradation rates cause long contaminant plumes. Some NSO-HET are highly toxic and carcinogenic (Sagner et al. 2007, Eisenträger et al. 2008). Aerobic biological degradation was found to be effective in batch and column experiments. Based on the hydro-geology of the quartenary aquifer and the contaminant situation along the plume (800 m long, 70 m wide) downstream of a former gasworks site (Testfeld Süd, TFS) in Stuttgart, Germany, an applicable technology to enhance the natural degradation of PAH and NSO-HET was selected. The technology wa...
The detection of fecal viral pathogens in water is hampered by their great variety and complex an... more The detection of fecal viral pathogens in water is hampered by their great variety and complex analysis. As traditional bacterial indicators are poor viral indicators, there is a need for alternative methods, such as the use of somatic coliphages, which have been included in water safety regulations in recent years. Some researchers have also recommended the use of reference viral pathogens such as noroviruses or other enteric viruses to improve the prediction of fecal viral pollution of human origin. In this work, phages previously tested in microbial source tracking studies were compared with norovirus and adenovirus for their suitability as indicators of human fecal viruses. The phages, namely those infecting human-associated Bacteroides thetaiotaomicron strain GA17 (GA17PH) and porcine-associated Bacteroides strain PG76 (PGPH), and the human-associated crAssphage marker (crAssPH), were evaluated in sewage samples and fecal mixtures obtained from different animals in five Europea...
In recent months, wastewater-based epidemiology (WBE) has been shown to be an important tool for ... more In recent months, wastewater-based epidemiology (WBE) has been shown to be an important tool for early detection of SARS-CoV-2 circulation in the population. In this study, a detection methodology for SARS-CoV-2 RNA (wild-type and variants of concern) in wastewater was developed based on the detection of different target genes (E and ORF1ab) by PEG precipitation and digital droplet PCR. This methodology was used to determine the SARS-CoV-2 concentration and the proportion of N501Y mutation in raw sewage of the wastewater treatment plant of the city of Karlsruhe in southwestern Germany over a period of 1 year (June 2020 to July 2021). Comparison of SARS-CoV-2 concentrations with reported COVID-19 cases in the catchment area showed a significant correlation. Viral RNA titre trends appeared more than 12 days earlier than clinical data, demonstrating the potential of wastewater-based epidemiology as an early warning system. Parallel PCR analysis using seven primer and probe systems reve...
Chloroethenes belong to the most widely distributed groundwater contaminants. Since 2014, it has ... more Chloroethenes belong to the most widely distributed groundwater contaminants. Since 2014, it has been known that trichloroethene (TCE) can be degraded aerobically and metabolically as growth substrate by a mixed bacterial enrichment culture (named SF culture). In this study, the degradation capabilities under a range of field-relevant conditions were investigated in fixed-bed reactors as well as in batch experiments. Aerobic metabolic TCE degradation was stable over the long term, with degradation optima at 22 °C and pH 7. Degradation of up to 400 μM TCE was observed. The longest starvation period after which degradation of TCE was regained was 112 days. The possible co-contaminants perchloroethene, trans-1,2-dichloroethene, and cis-1,2-dichloroethene did not inhibit TCE degradation, even though they were not degraded themselves. The presence of equimolar amounts of 1,1-dichloroethene and vinyl chloride inhibited TCE degradation. Experiments with groundwater from different chloroethene-contaminated field sites proved the potential of the SF culture for bioaugmentation. Thus, aerobic metabolic TCE degradation should be considered as a promising method for the bioremediation of field sites with TCE as the main contaminant.
Perfluoroalkyl and polyfluoroalkyl substances (PFASs) represent hazardous pollutants and are freq... more Perfluoroalkyl and polyfluoroalkyl substances (PFASs) represent hazardous pollutants and are frequently detected in the environment, e.g. in contaminated groundwater. PFASs are persistent to biodegradation and conventional oxidation processes such as ozonation. In this study electrochemical degradation of PFASs on boron-doped diamond (BDD) electrodes is demonstrated. Experiments were performed with model solutions and contaminated groundwater with a dissolved organic carbon (DOC) content of 13 mg/L. The perfluorinated carboxylic acids (PFCAs) perfluorobutanoate, perfluoropentanoate, perfluorohexanoate, perfluoroheptanoate and perfluorooctanoate, and the perfluorinated sulfonic acids (PFSAs) perfluorobutane sulfonate, perfluorohexane sulfonate, perfluorooctane sulfonate and 6:2 fluorotelomer sulfonate were detected in the groundwater samples. At PFAS concentrations ranging from 0.26 to 34 mg/L (0.7 to 79 μM), the degradation of PFASs was achieved despite of the high DOC background. P...
Waterborne viruses are increasingly being considered in risk assessment schemes. In general, viru... more Waterborne viruses are increasingly being considered in risk assessment schemes. In general, virus detection by culture methods is time consuming. In contrast, detection by quantitative polymerase chain reaction (qPCR) is more rapid and therefore, more suitable for monitoring. At present, qPCR lacks the essential ability for discriminating between infectious and non-infectious viruses, thus limiting its applicability for monitoring disinfection processes. In this study, a method was developed to quantify UV inactivation by long amplicon (LA)-qPCR. Bacteriophage phiX174 was used as a surrogate for human pathogenic viruses. A qPCR protocol was developed with new sets of primers, resulting in amplicon lengths of 108, 250, 456, 568, 955, 1063, 1544, and 1764 nucleotides. The log reduction of gene copies increased with increasing amplicon length. Additional treatment with the intercalating dye, PMA, had no effect, indicating that the bacteriophage capsids were not damaged by low pressure...
The Tai Hu (Tai Lake) is used as a raw water reservoir for approximately ten million inhabitants ... more The Tai Hu (Tai Lake) is used as a raw water reservoir for approximately ten million inhabitants predominantly in Jiangsu province, China. Algal/cyanobacterial blooms occur frequently in the eutrophic shallow lake and present a challenge for drinking water treatment. Furthermore, occasionally taste and odor (T&O) problems have been reported in drinking water. Due to the impacts of wastewater and surface water runoff, pesticides and emerging pollutants such as pharmaceutical compounds must be considered as well.
A full scale funnel-and-gate biobarrier is developed for the removal of tar oil pollutants at an ... more A full scale funnel-and-gate biobarrier is developed for the removal of tar oil pollutants at an abandoned tar factory site near the city of Offenbach, Germany. Laboratory and on-site column studies were done to determine the operation parameters for microbiological clean-up of the groundwater polluted with 12,000 µg/L BTEX, 4,800 µg/L PAH, and 4,700 µg/L heterocylic compounds. In the laboratory study, a residence time of approx. 70 h proved to be sufficient for aerobic pollutant biodegradation. Up to 180 mg/L hydrogen peroxide (H2O2) were added and did not lead to any toxic effects to the degrading bacteria. The feasibility of the concept was confirmed in the on-site pilot study performed with a sedimentation tank (removal of ferric iron) and two bioreactors. In the bioreactors, >99.5 % of the pollutants were degraded. Biodegradation activity corresponded to a significant increase in numbers of pollutant degrading bacteria. In the bioreactors, a fast dissociation of H2O2 was obs...
Polyether sulfone Multibore® ultrafiltration membranes were modified using polyelectrolyte multil... more Polyether sulfone Multibore® ultrafiltration membranes were modified using polyelectrolyte multilayers via the layer-by-layer (LbL) technique in order to increase their rejection capabilities towards salts and antibiotic resistance genes. The modified capillary membranes were characterized to exhibit a molecular weight cut-off (at 90% rejection) of 384 Da. The zeta-potential at pH 7 was −40 mV. Laboratory tests using single-fiber modified membrane modules were performed to evaluate the removal of antibiotic resistance genes; the LbL-coated membranes were able to completely retain DNA fragments from 90 to 1500 nt in length. Furthermore, the pure water permeability and the retention of single inorganic salts, MgSO4, CaCl2 and NaCl, were measured using a mini-plant testing unit. The modified membranes had a retention of 80% toward MgSO4 and CaCl2 salts, and 23% in case of NaCl. The modified membranes were also found to be stable against mechanical backwashing (up to 80 LMH) and chemica...
Microbial degradation represents the key process for pollutant elimination in groundwater and soi... more Microbial degradation represents the key process for pollutant elimination in groundwater and soil. A careful and site-specific evaluation and monitoring is a prerequisite for the responsible application of the intrinsic bioremediation (natural attenuation) concept. In this paper, a case study focussing on tar oil pollutants is presented. Intrinsic biodegradation of PAH, BTEX, and heterocyclic aromatics was demonstrated by analysis of pollutant profiles, groundwater hydrochemistry, composition of the microflora, and microcosm studies. Aerobic as well as anaerobic processes in the presence of nitrate, Fe(lll), or sulfate, contributed to microbial pollutant elimination.
Heterocyclic hydrocarbons (NSO-HET) containing nitrogen (N), sulphur (S) or oxygen (O) atoms are ... more Heterocyclic hydrocarbons (NSO-HET) containing nitrogen (N), sulphur (S) or oxygen (O) atoms are constitutes of tar oil, commonly found downstream of former gasworks sites (Zamfirescu & Grathwohl, 2001, Piepenbrink et al. 2005). Typical NSO-HET ́s are benzofuran, methyl-benzofurans, methylquinolines, acridine or carbazole. Different field studies indicate that most NSO-HET are highly mobile due to their high water solubility. The low anaerobic biodegradation rates cause long contaminant plumes. Some NSO-HET are highly toxic and carcinogenic (Sagner et al. 2007, Eisenträger et al. 2008). Aerobic biological degradation was found to be effective in batch and column experiments. Based on the hydro-geology of the quartenary aquifer and the contaminant situation along the plume (800 m long, 70 m wide) downstream of a former gasworks site (Testfeld Süd, TFS) in Stuttgart, Germany, an applicable technology to enhance the natural degradation of PAH and NSO-HET was selected. The technology wa...
The detection of fecal viral pathogens in water is hampered by their great variety and complex an... more The detection of fecal viral pathogens in water is hampered by their great variety and complex analysis. As traditional bacterial indicators are poor viral indicators, there is a need for alternative methods, such as the use of somatic coliphages, which have been included in water safety regulations in recent years. Some researchers have also recommended the use of reference viral pathogens such as noroviruses or other enteric viruses to improve the prediction of fecal viral pollution of human origin. In this work, phages previously tested in microbial source tracking studies were compared with norovirus and adenovirus for their suitability as indicators of human fecal viruses. The phages, namely those infecting human-associated Bacteroides thetaiotaomicron strain GA17 (GA17PH) and porcine-associated Bacteroides strain PG76 (PGPH), and the human-associated crAssphage marker (crAssPH), were evaluated in sewage samples and fecal mixtures obtained from different animals in five Europea...
In recent months, wastewater-based epidemiology (WBE) has been shown to be an important tool for ... more In recent months, wastewater-based epidemiology (WBE) has been shown to be an important tool for early detection of SARS-CoV-2 circulation in the population. In this study, a detection methodology for SARS-CoV-2 RNA (wild-type and variants of concern) in wastewater was developed based on the detection of different target genes (E and ORF1ab) by PEG precipitation and digital droplet PCR. This methodology was used to determine the SARS-CoV-2 concentration and the proportion of N501Y mutation in raw sewage of the wastewater treatment plant of the city of Karlsruhe in southwestern Germany over a period of 1 year (June 2020 to July 2021). Comparison of SARS-CoV-2 concentrations with reported COVID-19 cases in the catchment area showed a significant correlation. Viral RNA titre trends appeared more than 12 days earlier than clinical data, demonstrating the potential of wastewater-based epidemiology as an early warning system. Parallel PCR analysis using seven primer and probe systems reve...
Chloroethenes belong to the most widely distributed groundwater contaminants. Since 2014, it has ... more Chloroethenes belong to the most widely distributed groundwater contaminants. Since 2014, it has been known that trichloroethene (TCE) can be degraded aerobically and metabolically as growth substrate by a mixed bacterial enrichment culture (named SF culture). In this study, the degradation capabilities under a range of field-relevant conditions were investigated in fixed-bed reactors as well as in batch experiments. Aerobic metabolic TCE degradation was stable over the long term, with degradation optima at 22 °C and pH 7. Degradation of up to 400 μM TCE was observed. The longest starvation period after which degradation of TCE was regained was 112 days. The possible co-contaminants perchloroethene, trans-1,2-dichloroethene, and cis-1,2-dichloroethene did not inhibit TCE degradation, even though they were not degraded themselves. The presence of equimolar amounts of 1,1-dichloroethene and vinyl chloride inhibited TCE degradation. Experiments with groundwater from different chloroethene-contaminated field sites proved the potential of the SF culture for bioaugmentation. Thus, aerobic metabolic TCE degradation should be considered as a promising method for the bioremediation of field sites with TCE as the main contaminant.
Perfluoroalkyl and polyfluoroalkyl substances (PFASs) represent hazardous pollutants and are freq... more Perfluoroalkyl and polyfluoroalkyl substances (PFASs) represent hazardous pollutants and are frequently detected in the environment, e.g. in contaminated groundwater. PFASs are persistent to biodegradation and conventional oxidation processes such as ozonation. In this study electrochemical degradation of PFASs on boron-doped diamond (BDD) electrodes is demonstrated. Experiments were performed with model solutions and contaminated groundwater with a dissolved organic carbon (DOC) content of 13 mg/L. The perfluorinated carboxylic acids (PFCAs) perfluorobutanoate, perfluoropentanoate, perfluorohexanoate, perfluoroheptanoate and perfluorooctanoate, and the perfluorinated sulfonic acids (PFSAs) perfluorobutane sulfonate, perfluorohexane sulfonate, perfluorooctane sulfonate and 6:2 fluorotelomer sulfonate were detected in the groundwater samples. At PFAS concentrations ranging from 0.26 to 34 mg/L (0.7 to 79 μM), the degradation of PFASs was achieved despite of the high DOC background. P...
Waterborne viruses are increasingly being considered in risk assessment schemes. In general, viru... more Waterborne viruses are increasingly being considered in risk assessment schemes. In general, virus detection by culture methods is time consuming. In contrast, detection by quantitative polymerase chain reaction (qPCR) is more rapid and therefore, more suitable for monitoring. At present, qPCR lacks the essential ability for discriminating between infectious and non-infectious viruses, thus limiting its applicability for monitoring disinfection processes. In this study, a method was developed to quantify UV inactivation by long amplicon (LA)-qPCR. Bacteriophage phiX174 was used as a surrogate for human pathogenic viruses. A qPCR protocol was developed with new sets of primers, resulting in amplicon lengths of 108, 250, 456, 568, 955, 1063, 1544, and 1764 nucleotides. The log reduction of gene copies increased with increasing amplicon length. Additional treatment with the intercalating dye, PMA, had no effect, indicating that the bacteriophage capsids were not damaged by low pressure...
The Tai Hu (Tai Lake) is used as a raw water reservoir for approximately ten million inhabitants ... more The Tai Hu (Tai Lake) is used as a raw water reservoir for approximately ten million inhabitants predominantly in Jiangsu province, China. Algal/cyanobacterial blooms occur frequently in the eutrophic shallow lake and present a challenge for drinking water treatment. Furthermore, occasionally taste and odor (T&O) problems have been reported in drinking water. Due to the impacts of wastewater and surface water runoff, pesticides and emerging pollutants such as pharmaceutical compounds must be considered as well.
A full scale funnel-and-gate biobarrier is developed for the removal of tar oil pollutants at an ... more A full scale funnel-and-gate biobarrier is developed for the removal of tar oil pollutants at an abandoned tar factory site near the city of Offenbach, Germany. Laboratory and on-site column studies were done to determine the operation parameters for microbiological clean-up of the groundwater polluted with 12,000 µg/L BTEX, 4,800 µg/L PAH, and 4,700 µg/L heterocylic compounds. In the laboratory study, a residence time of approx. 70 h proved to be sufficient for aerobic pollutant biodegradation. Up to 180 mg/L hydrogen peroxide (H2O2) were added and did not lead to any toxic effects to the degrading bacteria. The feasibility of the concept was confirmed in the on-site pilot study performed with a sedimentation tank (removal of ferric iron) and two bioreactors. In the bioreactors, >99.5 % of the pollutants were degraded. Biodegradation activity corresponded to a significant increase in numbers of pollutant degrading bacteria. In the bioreactors, a fast dissociation of H2O2 was obs...
Polyether sulfone Multibore® ultrafiltration membranes were modified using polyelectrolyte multil... more Polyether sulfone Multibore® ultrafiltration membranes were modified using polyelectrolyte multilayers via the layer-by-layer (LbL) technique in order to increase their rejection capabilities towards salts and antibiotic resistance genes. The modified capillary membranes were characterized to exhibit a molecular weight cut-off (at 90% rejection) of 384 Da. The zeta-potential at pH 7 was −40 mV. Laboratory tests using single-fiber modified membrane modules were performed to evaluate the removal of antibiotic resistance genes; the LbL-coated membranes were able to completely retain DNA fragments from 90 to 1500 nt in length. Furthermore, the pure water permeability and the retention of single inorganic salts, MgSO4, CaCl2 and NaCl, were measured using a mini-plant testing unit. The modified membranes had a retention of 80% toward MgSO4 and CaCl2 salts, and 23% in case of NaCl. The modified membranes were also found to be stable against mechanical backwashing (up to 80 LMH) and chemica...
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