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Papers by Ekaterina Sokolova

Research paper thumbnail of Hydrodynamic modelling of the microbial water quality in a drinking water source as input for risk reduction management

Citation for the published paper: Sokolova, E. ; Pettersson, T. ; Bergstedt, O. (2013) "Hydrodyna... more Citation for the published paper: Sokolova, E. ; Pettersson, T. ; Bergstedt, O. (2013) "Hydrodynamic modelling of the microbial water quality in a drinking water source as input for risk reduction management".

Research paper thumbnail of Hydrodynamic modelling and forecasting of microbial water quality in a drinking water source

ABSTRACT Faecal contamination often enters drinking water sources through emergency discharges, w... more ABSTRACT Faecal contamination often enters drinking water sources through emergency discharges, which occur as a result of technical malfunctions or a hydraulic overload of the sewer system during periods of heavy rain. In October-November 2012, several emergency discharges entered Lake Radasjon - a drinking water source for Gothenburg, Sweden. To describe and forecast the influence of these emergency discharges on the microbial water quality, the spread of Escherichia coli ( E. coli) within the lake was simulated using a three-dimensional hydrodynamic model. The model was run for a period of 4 months using the observed data, and for a period of 9 days using meteorological forecast data. The modelling results showed how much every contamination source contributed to the total E. coli concentrations at the water intakes. The agreement between the modelling results and the measured concentrations was satisfactory. The results of this study led to the decision to use the lake for drinking water production. This study demonstrated that the proposed modelling approach can be used to provide short-term forecasts of the microbial water quality in drinking water sources.

Research paper thumbnail of Estimation of pathogen concentrations in a drinking water source using hydrodynamic modelling and microbial source tracking

Journal of Water and Health, 2012

Citation for the published paper: Sokolova, E. ; Åström, J. ; Pettersson, T. (2012) "Estimation o... more Citation for the published paper: Sokolova, E. ; Åström, J. ; Pettersson, T. (2012) "Estimation of pathogen concentrations in a drinking water source using hydrodynamic modelling and microbial source tracking".

Research paper thumbnail of Decay of Bacteroidales Genetic Markers in Relation to Traditional Fecal Indicators for Water Quality Modeling of Drinking Water Sources

Environmental Science & Technology, 2012

The implementation of microbial fecal source tracking (MST) methods in drinking water management ... more The implementation of microbial fecal source tracking (MST) methods in drinking water management is limited by the lack of knowledge on the transport and decay of host-specific genetic markers in water sources. To address these limitations, the decay and transport of human (BacH) and ruminant (BacR) fecal Bacteroidales 16S rRNA genetic markers in a drinking water source (Lake Radasjon in Sweden) were simulated using a microbiological model coupled to a three-dimensional hydrodynamic model. The microbiological model was calibrated using data from outdoor microcosm trials performed in March, August, and November 2010 to determine the decay of BacH and BacR markers in relation to traditional fecal indicators. The microcosm trials indicated that the persistence of BacH and BacR in the microcosms was not significantly different from the persistence of traditional fecal indicators. The modeling of BacH and BacR transport within the lake illustrated that the highest levels of genetic markers at the raw water intakes were associated with human fecal sources (onsite sewers and emergency sewer overflow). This novel modeling approach improves the interpretation of MST data, especially when fecal pollution from the same host group is released into the water source from different sites in the catchment.

Research paper thumbnail of Microbial risk assessment of drinking water based on hydrodynamic modelling of pathogen concentrations in source water

Science of The Total Environment, 2015

Norovirus contamination of drinking water sources is an important cause of waterborne disease out... more Norovirus contamination of drinking water sources is an important cause of waterborne disease outbreaks. Knowledge on pathogen concentrations in source water is needed to assess the ability of a drinking water treatment plant (DWTP) to provide safe drinking water. However, pathogen enumeration in source water samples is often not sufficient to describe the source water quality. In this study, the norovirus concentrations were characterised at the contamination source, i.e. in sewage discharges. Then, the transport of norovirus within the water source (the river Göta älv in Sweden) under different loading conditions was simulated using a hydrodynamic model. Based on the estimated concentrations in source water, the required reduction of norovirus at the DWTP was calculated using quantitative microbial risk assessment (QMRA). The required reduction was compared with the estimated treatment performance at the DWTP. The average estimated concentration in source water varied between 4.8×10(2) and 7.5×10(3) genome equivalents L(-1); and the average required reduction by treatment was between 7.6 and 8.8 Log10. The treatment performance at the DWTP was estimated to be adequate to deal with all tested loading conditions, but was heavily dependent on chlorine disinfection, with the risk of poor reduction by conventional treatment and slow sand filtration. To our knowledge, this is the first article to employ discharge-based QMRA, combined with hydrodynamic modelling, in the context of drinking water.

Research paper thumbnail of Hydrodynamic modelling of the microbial water quality in a drinking water source as input for risk reduction management

Citation for the published paper: Sokolova, E. ; Pettersson, T. ; Bergstedt, O. (2013) "Hydrodyna... more Citation for the published paper: Sokolova, E. ; Pettersson, T. ; Bergstedt, O. (2013) "Hydrodynamic modelling of the microbial water quality in a drinking water source as input for risk reduction management".

Research paper thumbnail of Hydrodynamic modelling and forecasting of microbial water quality in a drinking water source

ABSTRACT Faecal contamination often enters drinking water sources through emergency discharges, w... more ABSTRACT Faecal contamination often enters drinking water sources through emergency discharges, which occur as a result of technical malfunctions or a hydraulic overload of the sewer system during periods of heavy rain. In October-November 2012, several emergency discharges entered Lake Radasjon - a drinking water source for Gothenburg, Sweden. To describe and forecast the influence of these emergency discharges on the microbial water quality, the spread of Escherichia coli ( E. coli) within the lake was simulated using a three-dimensional hydrodynamic model. The model was run for a period of 4 months using the observed data, and for a period of 9 days using meteorological forecast data. The modelling results showed how much every contamination source contributed to the total E. coli concentrations at the water intakes. The agreement between the modelling results and the measured concentrations was satisfactory. The results of this study led to the decision to use the lake for drinking water production. This study demonstrated that the proposed modelling approach can be used to provide short-term forecasts of the microbial water quality in drinking water sources.

Research paper thumbnail of Estimation of pathogen concentrations in a drinking water source using hydrodynamic modelling and microbial source tracking

Journal of Water and Health, 2012

Citation for the published paper: Sokolova, E. ; Åström, J. ; Pettersson, T. (2012) "Estimation o... more Citation for the published paper: Sokolova, E. ; Åström, J. ; Pettersson, T. (2012) "Estimation of pathogen concentrations in a drinking water source using hydrodynamic modelling and microbial source tracking".

Research paper thumbnail of Decay of Bacteroidales Genetic Markers in Relation to Traditional Fecal Indicators for Water Quality Modeling of Drinking Water Sources

Environmental Science & Technology, 2012

The implementation of microbial fecal source tracking (MST) methods in drinking water management ... more The implementation of microbial fecal source tracking (MST) methods in drinking water management is limited by the lack of knowledge on the transport and decay of host-specific genetic markers in water sources. To address these limitations, the decay and transport of human (BacH) and ruminant (BacR) fecal Bacteroidales 16S rRNA genetic markers in a drinking water source (Lake Radasjon in Sweden) were simulated using a microbiological model coupled to a three-dimensional hydrodynamic model. The microbiological model was calibrated using data from outdoor microcosm trials performed in March, August, and November 2010 to determine the decay of BacH and BacR markers in relation to traditional fecal indicators. The microcosm trials indicated that the persistence of BacH and BacR in the microcosms was not significantly different from the persistence of traditional fecal indicators. The modeling of BacH and BacR transport within the lake illustrated that the highest levels of genetic markers at the raw water intakes were associated with human fecal sources (onsite sewers and emergency sewer overflow). This novel modeling approach improves the interpretation of MST data, especially when fecal pollution from the same host group is released into the water source from different sites in the catchment.

Research paper thumbnail of Microbial risk assessment of drinking water based on hydrodynamic modelling of pathogen concentrations in source water

Science of The Total Environment, 2015

Norovirus contamination of drinking water sources is an important cause of waterborne disease out... more Norovirus contamination of drinking water sources is an important cause of waterborne disease outbreaks. Knowledge on pathogen concentrations in source water is needed to assess the ability of a drinking water treatment plant (DWTP) to provide safe drinking water. However, pathogen enumeration in source water samples is often not sufficient to describe the source water quality. In this study, the norovirus concentrations were characterised at the contamination source, i.e. in sewage discharges. Then, the transport of norovirus within the water source (the river Göta älv in Sweden) under different loading conditions was simulated using a hydrodynamic model. Based on the estimated concentrations in source water, the required reduction of norovirus at the DWTP was calculated using quantitative microbial risk assessment (QMRA). The required reduction was compared with the estimated treatment performance at the DWTP. The average estimated concentration in source water varied between 4.8×10(2) and 7.5×10(3) genome equivalents L(-1); and the average required reduction by treatment was between 7.6 and 8.8 Log10. The treatment performance at the DWTP was estimated to be adequate to deal with all tested loading conditions, but was heavily dependent on chlorine disinfection, with the risk of poor reduction by conventional treatment and slow sand filtration. To our knowledge, this is the first article to employ discharge-based QMRA, combined with hydrodynamic modelling, in the context of drinking water.