Microbial risk management in water systems HARTEMANN P. NANCY-UNIVERSITY Department Environment & Public Health Uni

1. Microbial risk management in water systems HARTEMANN P. NANCY-UNIVERSITY Department Environment & Public Health United Arab Emirates Conference Sunday November 30th - DUBAI

2. Production and Transport of drinking water Network

3. 1.Microbial characteristics of drinking water

4. Bacteria Negatively charged 1 µm Hydrophobic zones 0.2 pg For facing constantly changing environment, life principles (perception/action) implie optimization of recognition systems : - sensors, probes. - communication. - nutrient search - morphogenic cycles

5. Colony forming units on agar medium Strong underestimation of the real number of alive bacteria

6. Ciliés Flagellés Amibes Amibes

7. Microcrustacae: genus Asellus few mm to 1 cm

8. Other bugs 100 µm

9. Microorganisms in drinking water - highly diversified flora (bacteria, fungi, yeasts,…) - 107 to 108 bacteria cells / L (1 to 10% are viable) - protozoa : around 105 / L - macroinvertebrates : around 103 / L • oligotrophic environment (1mg TOC/L with 0.3 mg biodegradable organic carbon) • No analysis of the bacterial population (pathogens ?)

10. 2.Is public drinking water safe ?

11. Water consumptionTotal ingesta : 3 L / d x capitaDrinks and water daily intake : 2 to 2,5 L / d x capitaRaw tap water daily intake : 47 to 322 mL / d x capita( to 1L in countries where bottled waters are rare )

12. Epidemiological studies Monto and Koopman (1980) - USA Payment et al. (1991 et 1997) - Canada Zmirou et al. (1986) - France Gofti and Zmirou (2001) - France Hellard et al. (2001) - Australia Drinking water meeting microbiological standards may be cause of GI symptoms (excess of risk : 20 to 35 % of the exposed population)

13. 0.2 gastrointestinal illness/person-year with 10 to 30% associated to the consumption of potable tap water 10% of the contaminated people lost at least 1 day of work around 1 million of working-days lost in EU due to waterborne illness in relation with potable drinking water

14. 3. Microbial risk management in water systems

15. Vulnerability of drinking water systems: Intrusion of microorganisms Back-contamination Treated water Water distribution systems The major source of pathogens comparatively to breakthroughs (Westrell et al., 2003) Bacterial growth (70 to 90% of the biomass is produced in the biofilm) Breakthrough

16. Hospital with 800 beds 200 L water/bed.day (all uses) Around 10 km of pipes (iron, galvanized, cupper, PVC ) Around 5,000 points of use

17. Epidemiological evidences There is a potential health risk from intrusion of microorganisms into the hospital distribution systems Drinking (water and ice), bathing and shower, contacting medical equipment rinsed with tap water, direct contact with the patients from tap water outlets Pseudomonas aeruginosa (and others), Mycobacterium, Legionella, Acinetobacter, K,E,S, Sphingomonas, fungi…

18. Action 1 : Controlling drinking water quality before entering the building No cultivable E. coli, no cultivable Pseudomonas aeruginosa but pathogens and opportunistic pathogens + Biodegradable organic matter

19. ( ) CAP ( ) CAP ( ) CAP ( ) CAP Coaguant Coagulation sur filtre Coagulant Clarification complète : colloids and particles removal Coagulant Charbon actif en premier étage : pollutant sorption Coagulant Charbon actif en deuxième étage Coagulant Ozone Clarification - ozonation Charbon actif organic matter removal oxidation/desinfection (0.3 mg/L residual chlorine) Membrane filtration !!!

20. Action 2 Network structure organisation Separation of the network into independant subsections, Preventing backflow (valves), No dead-ends, Clean softeners, Choice of material pipes (uncorrodable metallic pipes , no organic leaching from plastic pipes)

21. Action 3 Limiting biofilm activity and production

23. Biofilm in drinking water system Simultaneous hybridization of a colony with the FLUOS-labeled probe (green) specific for the gamma subclass and TRITC-labeled probe (yellow red) specific for the beta subclass of Proteobacteria shown by epifluorescence (Manz et al. 1993)

24. Diatom associated with surfaces in potable water (Percival et al. 2000)

25. Biofilm accumulation on plastic pipes in drinking water at 20°C (adapted from Batté et al. 2003) Cells stained with DAPI Bacterial density (Cells or CFU) cm-2 Culturable bacteria on R2A agar Time of colonisation (weeks)

26. Biofilms on materials(water velocity: 1 m s-1; température: 20oC; 6 weeks)

27. Action 4 Effective dose of disinfectant ?

28. HClO HClO HClO Cell response Diffusion limitation in the biofilm

29. 12.5 10 7.5 5 2.5 0 Comparison at initial time of the rate of chlorine consumption ( [Cl2] 0 = 5 mg L-1; T= 20°C; pH = 9 ) Chlorine consumption (mg Cl2 L-1 h-1) Water Biofilm Cement

30. Almost no diffusion of chlorine in the biofilm Chlorine (mg/l) Chlore dans l’eau 10 matériau Cl02 > NH2Cl > Cl2 ?? (Srinivasan et al., 2003) (Heffelfinger et al., 2003) 1 0 Biofilm 400 µm DeBeer et al., 1994

31. Bacteria Chlorine in the distribution system Nutrients : 1 - 5 mg L-1 DOC 30% BDOC Chlorine concentration Particule Protozoa Biofilm : 103 to 107 cells cm-2 1 to 5 % cultivables cement Cast iron

32. HClO HClO HClO Cell response Diffusion limitation in the biofilm Diffusion limitation in the cells

33. Injured Viable bacteria C A B HClO - culturable - respiratory activity DAPI-stained E. coli observed by epifluorescence microscopy. (A): Initial suspension. (B): +15 mg of chlorine/L during 90 min. (C): +25 mg of chlorine/L during 90 min. low - high fluorescence after DNA staining by DAPI Staining E. coli by 4’,6-diamidino-2-phenylindole (DAPI)

34. HClO HClO HClO Cell response Diffusion limitation in the biofilm Diffusion limitation in the cells Resistance to the oxidative stress

35. Around 40 different mechanisms of resistance to oxidate stress inE. coli (Storz and Hengge-Aronis, 2000) Key example : Glutathion Glutamate + ATP + Cystéine = ADP + Pi+ Gamma glutamylcystéine + ATP + Glycine = ADP + Pi +

36. Survival of prechlorinated Escherichia coli to a second chlorination

37. Resistance to chlorine after sublethal exposure to chlorine Chlorine (mg/l) Chlore dans l’eau 10 matériau 1 0 Biofilm 400 µm DeBeer et al., 1994

38. Action 5 Decentralized water treatment (filtration at the point of use)

41. Action 6 Develop a programme for rapid and frequent monitoring of water systems Quantitative PCR, FISH, … versus bacterial culture

42. CONCLUSIONS

43. Network = bioreactor DOC : 1 to 5 mg/L BDOC : 30% DOC Cells : 107/L Bacterial growth 1 2 Total cells : 108 /L OXIDATIVE STRESS (O2 ; chlorine) HPC : 104 /L VNC : 106 cells/L BIOFILM

44. Recommendations for preventing nosocomial waterborne infections Don’t go near the water (minimize patient exposure) Improved technical quidelines (some of the recommendations are sometimes unappropriateex: TOC<0.2 mg/Lor too general ex: effective disinfectant Cl2, Cl02, NH2Cl, Peracetic acid+H2O2,…?): in situ testing needed ? Improved infection control measures : decentralized actions (water filtration, …) Routine rapid surveillance of water systems (including temperature)