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EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 1 Microbiological Risk Assessment.

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Presentation on theme: "EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 1 Microbiological Risk Assessment."— Presentation transcript:

1 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 1 Microbiological Risk Assessment A scientific basis for managing drinking water safety from source to tap www.microrisk.com MICRORISK

2 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 2 Microbiologically safe drinking water Council directive 98/83/EC Article 1. Objective is to protect human health from the adverse effects of any contamination by ensuring that it is wholesome and clean. Article 4. Water is wholesome and clean if it is free from any micro-organisms and parasites and from any substances which, in numbers or concentrations, constitute a potential danger to human health Operationally translated (Article 4) into meeting the requirements in Annex I. Microbiological safety: E.coli 0/100ml(Clostridium perfringens 0/100ml) enterococci 0/100ml

3 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 3 E.coli as quality standard Milestone 1: culture media for bacteria 1885 - 1908 Professor Hygiene Berlin 1879: first proof of bacteria (anthrax) as agents of disease 1881: solid culture media for isolation of bacteria 1883: isolation of causative agent of cholera 1905: Nobelprice Physiology and Medicine Robert Koch (1843-1910)

4 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 4 E.coli as quality standard Milestone 2: indicator-bacteria 1898 -1929 Professor Hygiene RU Utrecht 1904: Method for detection of fecal contamination of water with test at 46°C (Eijkman- test) 1929: Nobelprice Physiology and Medicine (discovery of role of vitamins) Christiaan Eijkman (1858-1930)

5 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 5 The indicator concept Presence of bacteria that are abundant in human and animal feces (E.coli, enterococci) in water indicates health risk (pathogens may be present) Absence of indicator bacteria are indication of safety

6 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 6 Connections to water supply and incidence of typhoid % connection to mains supply Cases of typhoid per 100000

7 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 7 E. coli has served us well, but…. Too late Outbreaks in absence of E. coli “New” pathogens more resistant Demonstrate due diligence: not retrospective but proactive Consumer health & safety moving towards risk approach (food safety) Scientific development of QMRA WHO: Water Safety Plans IWA: Bonn charter

8 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 8 Microbiological Risk Assessment A scientific basis for managing drinking water safety from source to tap www.microrisk.com MICRORISK

9 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 9 Objective Provide scientific basis for QMRA Develop a harmonised, evaluated and validated framework for risk assessment, providing adequate information for risk management

10 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 10 Consortium Basic science - applied science - end users Kiwa Water Research Ondeo Services Centre for Water and Wastewater Technology, Australia Water Technology Centre Technical University Delft University of East Anglia Anjou Recherche Vivendi Water Partnership Insitute for Hygiene, Univ. Bonn Water Research Centre NSF Institute for Infectious Disease Control

11 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 11 Microrisk results Scientific data on pathogen occurrence, efficiency of treatment processes, distribution system integrity, consumption of drinking water QMRA using these data, (un)certainty assessment Comparison between QMRA and epidemiological data on GI-illness/waterborne outbreaks Protocol for QMRA, esp. exposure assessment

12 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 12

13 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 13 Waterborne outbreaks in Europe 1990-2004

14 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 14 Fault tree analysis

15 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 15 Factors causing the outbreaks Source failure Rainfall 44% livestock activity 41% Sewage discharge10% Treatment Chronic filtration failure38% Distribution Backflow/cross connection15% Detection Failure to recognize problem18%

16 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 16 CTS Locations 1 2 3 4 5 7 6 8 9 10

17 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 17 Source water

18 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 18 WP2 Source water quality Objective: design monitoring strategy for pathogens in raw water Peak events are risk events, so include peak events in the strategy First know your catchment, then design monitoring strategy. Catchment survey (sources, contamination level, indicators for peak events) Design and test monitoring strategy Several catchments, several pathogens

19 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 19 12 “Catchment to Tap Systems”

20 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 20 Pathogens of interest Parasites Cryptosporidium parvum Giardia intestinalis Bacteria Campylobacter Escherichia Coli O157:H7 Virus Enterovirus Norovirus

21 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 21 Catchment Survey Objectives : Identification of pathogen sources and occurrence of peak events Methodology: Location Description of water abstraction Description of the catchment -Hydrogeology & Hydrology -Climate -Land use Location & description of potential sources of faecal contamination Human Origin Animal Origin

22 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 22 Example for catchment description : CTS 3 Physical characteristics 0 40 80 120 JanMarchMayJulySeptNov Precipitation 0 5 10 15 20 Temperature Average precipitation (mm) Average temperature (°C) 45 m 910 m Impervious Pervious River 1 River 2 Forests & meadows Crops River 1 River 2 20 Km N

23 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 23 Example for catchment description : CTS 3 Human activities 0 10 20 30 40 50 Nuclear power plant IndustryAgricultureDrinking water Mm 3 /an Surface waterGround water Water uses Pathogen sources : animal breeding & WWTP Bovine Caprine Poultry Porcine Ovine WWTP 30 000 PE WWTP 25 000 PE WWTP 285 000 PE WWTP 160 000 PE Drinking water treatment plant N 20 Km

24 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 24 Example for catchment description : CTS 3 Occurrence of peak events Daily flow and turbidity 2002-2004 0 200 400 600 800 July-02Jan-03July-03Jan-04 m 3 /s 0 50 100 150 200 NTU Flow Turbidity r²=0,7 Peak  relatively rare event (9 peaks per year # 25%) Criteria : Q threshold =147 m 3 /s & T threshold =12 NTU

25 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 25 Raw water monitoring: what do we sample? CTS 3 France CTS 7 Germany Peak contamination monitoring

26 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 26 High bird loads

27 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 27 Campylobacter in off-stream storage reservoir water (1994 & 2001)

28 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 28 Bird counts on reservoir

29 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 29 Pathogens in source water summary

30 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 30 Conclusion Quantitative Microbiological Risk Assessment (QMRA) Know your catchment (survey it) in order to: Identify pathogen sources Occurrence and frequency of peak events Monitor your catchment in order to assess: Chronic contamination Magnitude of peak events

31 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 31 WP3 Treatment efficiency Objective: design strategy to describe and control treatment efficiency (QMRA and Water Safety Plan) Describe treatment efficiency (QMRA) Collect and review state-of-the-art Full scale indicator bacteria Full scale porcess parameters Pilot plant research

32 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 32 Treatment framework Literature review Mean Elimination Capacity MEC Reduction credits Based on unit processes Estimated pathogen elimination 4.2.2 4.2.34.2.44.2.54.2.6 4.2.7

33 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 33 Tier 1: Log credits MIN DECMAX DECMEC Efficacy of treatment process in literature (7 studies for one pathogen and one process) No site info Not disinfection

34 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 34 Tier 1: Log credits Quantify UNCERTAINTY MIN DECMAX DECMEC Apply triangular PDF No site info Not disinfection

35 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 35 Tier 2: Refine based on turb or design MIN DECMAX DECMEC POOR GOOD

36 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 36 Treatment framework Literature review Mean Elimination Capacity MEC Reduction credits Based on unit processes Estimated pathogen elimination Design Characteristics Specific MEC 4.2.2 4.2.34.2.44.2.54.2.6 4.2.7

37 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 37 Model from pilots and literature

38 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 38 Treatment models Temperature Ct DE (log removal) Coli untreated Coli treated & = * =

39 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 39 Treatment framework Literature review Mean Elimination Capacity MEC Full-scale measurements Variation of process Conditions at full scale Reduction credits Based on unit processes (On-line) Residuals Model Disinfection + Identify events Estimated pathogen elimination Design Characteristics Specific MEC (On-line) Surrogate Refine MEC+ Identify events 4.2.2 4.2.34.2.44.2.54.2.6 4.2.7

40 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 40

41 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 41 Clostridium spore removal over time 0,1 1,0 10,0 100,0 020040060080010001200 -> days SSRC per 100ml Influent Effluent Coagulation Ozone

42 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 42 Lab is not practice: ozone example Ozonation CT 2 mg.min/l Expected E. coli inactivation: >>5 logs Full scale E. coli data: -E. coli present in 4% of samples after ozone -Removal 2.7 log

43 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 43 Bad days: example of chlorination: inactivation modelled on CT, hydraulics and temperature

44 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 44 Pilot studies: Cryptosporidium removal by pilot slow sand filter

45 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 45 Treatment processeslog removal Coagulation-Sedimentation-Filtration-GAC filtration-Chlorination-4.3 Coagulation-Sedimentation-Filtration-GAC filtration-Ozone-Chlorination-4.3 Coagulation-Sedimentation-Filtration-GAC filtration-Chlorination-3.4 Coagulation-Sedimentation-Filtration-GAC filtration-Chlorination-3.3 Impoundment-Coagulation-Sedimentation-Dissolved Air Flotation-Filtration-GAC filtration-Chlorination- 3.2 Impoundment-Coagulation-Sedimentation-Filtration-GAC filtration-Chlorination-3.2 Coagulation-Sedimentation-GAC filtration-Ozone-Chlorination-3.1 Coagulation-Sedimentation-Filtration-GAC filtration-Chlorination-2.6 UK Crypto data: Treatment

46 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 46 Treatment framework Literature review Mean Elimination Capacity MEC Full-scale measurements Variation of process Conditions at full scale Reduction credits Based on unit processes (On-line) Residuals Model Disinfection + Identify events Estimated pathogen elimination Full-scale samples Pathogenic and indicator organisms before and after treatment Stochastic model Indicators Translate to Pathogens Direct Analysis Combined Indicators and Pathogens Design Characteristics Specific MEC (On-line) Surrogate Refine MEC+ Identify events 4.2.2 4.2.34.2.44.2.54.2.6 4.2.7 Available data Site specific

47 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 47 Total treatment Monte Carlo

48 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 48 Distribution

49 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 49 Distribution Faecal contamination incidents Netherlands 1994 – 2003 7 water companies 11 million people supplied 50 incidents reported 5 - 50,000 people affected per incident Probability of being affected by incident: 1.7 x 10 -3 pppy

50 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 50 Distribution incidents: duration

51 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 51 Distribution incidents: magnitude

52 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 52 Translation to pathogens E. coli data in distribution network No pathogen data E. coli AND pathogen data in sewage Assume: contamination source is sewage Use pathogen to E. coli ratio’s to translate E. coli to pathogens Sensitivity analysis: Pathogen/E.coli ratío from different matrices

53 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 53 Microrisk WP5: consumption How much cold tap water do we consume? What information is available? How reliable/useful is the available information? How is tap water consumption distributed? Can we come to a useful estimate for QMRA? literature review statistical analysis of data

54 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 54 Literature review Review available studies on tap water consumption > 25 studies found Evaluate design of the studies Way of recording consumption Factors that might influence tap water consumption

55 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 55 Study design (24h-) Dietary recall Retrospective Interview/questionnaire Measures recent consumption Dietary record/diary Prospective Measures current consumption Food frequency questionnaire Retrospective Consumption in general Combination of questionnaire & diary

56 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 56 Literature review: results Tap water consumption average consumer Cold tap water: 0.2 - 1.55 L/day Total tap water: 0.71 - 2.58 L/day Comparibility influenced by: Population participating Year of survey Season of data collection Method of data collection Method to assess volume tap water consumed Types of water included No conclusions regarding effects of age, season, gender on tap water consumption Physical activity, income and perceived health status were reported to increase consumption

57 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 57 Australia Final: case-control study sporadic cryptosporidiosis Melbourne & Adelaide (Q) (N = 950, N = 644) Melbourne best performance Poisson distr. Adelaide: again Poisson best, but poor similarity of shape Nr of non-consumers higher than nr consuming 1 glass Diary study in pilot most valuable

58 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 58 Recommendations for QMRA Use country specific data and distributions (when available) Use mean as conservative approach, instead of median (skewed distribution) Beware for inter-country AND intra-country differences (Adelaide vs Melbourne) Several datasets available? Use data generated with best study design Otherwise: use highest consumption estimates as conservative approach (data Melbourne)

59 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 59 Risk assessment

60 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 60 WP6 Risk assessment Objective: protocol for risk assessment (integration of WP2-5 and dose-response data) and protocol for uncertainty analysis Select most appropriate mathematical techniques for integration of information into risk assessment Include uncertainty analysis into protocol Case studies: evaluate protocol: determine risk and uncertainty level

61 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 61 Conceptual model

62 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 62 QMRA design

63 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 63 Monte Carlo

64 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 64 Statistical data analysis - output Probability of infection

65 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 65 Sensitivity analysis

66 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 66 Factor Sensitivity Results - Adelaide ParameterExpected Value Worst CaseFactor Sensitivity Source Water Concentration (oocyst.L-1) 0.251.40 Flow Rate (m3.s-1) 0.1510.82 EMC (oocyst.L-1) 2.25501.32 Event Volume (ML) 2135000.02 Reservoir Dilution Factor 960.18 Treatment Removal 4.522.50 Consumption 140.60 Event/Nominal 4.26

67 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 67 Effect of chlorination failure time

68 EU-5th Framework program: Energy, environment and sustainable development; project EVK1-CT-2002-00123: MICRORISK © Kiwa 2006 68 Microbiological Risk Assessment A scientific basis for managing drinking water safety from source to tap www.microrisk.com MICRORISK

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