Microbial risk assessment of drinking water based on hydrodynamic modelling of pathogen concentrations in source water.
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.
Chalmers University of Technology, Department of Civil and Environmental Engineering, Water Environment Technology, SE-412 96 Gothenburg, Sweden. Electronic address: ekaterina.sokolova@chalmers.se.
Ekaterina
E
Sokolova
Norwegian University of Life Sciences NMBU, Department of Mathematical Sciences and Technology, P.O. Box 5003, NO-1432 Ås, Norway; Water & Health Pty Ltd. P.O. Box 648 Salamander Bay, 2317, Australia.
Susan R
SR
Petterson
Ryhov County Hospital, Medical Services, Clinical Microbiology, SE-551 85 Jönköping, Sweden.
Olaf
O
Dienus
Ryhov County Hospital, Medical Services, Clinical Microbiology, SE-551 85 Jönköping, Sweden; Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology, SE-581 85 Linköping, Sweden.
Fredrik
F
Nyström
Ryhov County Hospital, Medical Services, Clinical Microbiology, SE-551 85 Jönköping, Sweden; Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology, SE-581 85 Linköping, Sweden.
Per-Eric
PE
Lindgren
Chalmers University of Technology, Department of Civil and Environmental Engineering, Water Environment Technology, SE-412 96 Gothenburg, Sweden.
Thomas J R
TJ
Pettersson
D060766:Drinking Water / Q000469:parasitology*; D004784:Environmental Monitoring; D057446:Hydrodynamics; D008962:Models, Theoretical; D018570:Risk Assessment / Q000379:methods; D014871:Water Microbiology; D060753:Water Quality / Q000592:standards*
D060766:Drinking Water
Discharge-based QMRA; Norovirus; QMRA; Quantitative microbial risk assessment; Water quality modelling