Session 11 The Incomplete Coliform Rule Maine Water Utilities Association February Show

Transcription

1 Session 11 The Incomplete Coliform Rule 2011 Maine Water Utilities Association February Show

2 Outline for Session Topic 1 - Biofilms and Distribution System Microbiology Presenter Jeff Musich P.E. Wright-Pierce Topic 2 The Total Coliform Rule (TCR) Revisions Presenter Jennifer Grant Maine Drinking Water Program

3 Biofilms and the Prevalence of Microbiological Contaminants in Water Distribution Systems 2011 Maine Water Utilities Association February Show Presenter: Jeff Musich P.E. Wright-Pierce

4 Outline Current Regulatory Basis for Disinfection Scientific Basis for TCR Future Regulations EPA s CCL 3 New Research on Prevalence of Microbes in Distribution Systems Biofilm Science Questions

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6 Scientific Basis for Water Disinfection in US Waterborne Disease from Pathogens Found in Fecal Contamination Provide Dual Barrier Treatment Systems: Filtration Disinfection (Ozone, Chlorine, UV, Chlorine Dioxide) Provide Disinfectant Residual for Microbial Inactivation: Giardia, Viruses, Cryptosporidium Provide Adequate CT (Contact Time x Conc.)

7 Scientific Basis for Total Coliform Rule (TCR) Total Coliforms (TC) are Non-Pathogenic Organisms found in Soil TC are Indicator Organisms Protect Distribution Systems from Breaches: Cross-Connection Control Sound Design Practices Treatment and Disinfection Routine Monitoring and Testing

8 Emerging Concerns Biofilm Research and Characterization Non-Fecal Human Pathogens Validity of Use of TC as a Surrogate Organism for Pathogens Are Current Disinfection Practices Adequate? Disinfectant Residual CT Pathogen Resistance

9 New Research Other Non-Fecal Organisms Live in Water Distribution Systems New Research: Other Organisms Can Cause Human Illness Current Disinfection Strategies May Not Apply Knowledge is Growing Biofilm Studies and Evaluations EPA s CCL 3 Emerging Microbiological Contaminants

10 EPAs Candidate Contaminant List (CCL 3) Draft List Published in October 2010 Public Comment on New Microbes: Viruses (4) Bacteria (7) Protozoa (1) What May be Regulated in the Future?

11 Potential Microbial Contaminants for Regulation by EPA (CCL 3) Viruses Adenovirus Causes Respiratory/Gastro. Illness Hepatitis A Liver Disease Enterovirus Respiratory Illness Bacteria Campylobacter jejuni Gastrointestinal Illness Legionella pneumophilia Lung Disease Salmonella enterica - Gastrointestinal Illness Mycobacterium avium Lung Infections

12 Ongoing Research on E. coli Efficacy E. coli may Remain Dormant in Pipe Tubercles Ferric Oxides in Anaerobic Conditions May Increase E. coli Viability (Apenzeller, et.al. 2005) Iron may Actually be a Nutrient 0.2 mg/l May be Inadequate for Distribution Systems (H.M. Murphy, et. al. 2005) OK for HPC, May not be OK for Pathogens

13 Colilert Test

14 E. coli in Biofilm from Active Cast Iron Water Main in England after Culturing in Laboratory using a Blue Filter E. coli in Biofilm from Active Cast Iron Water Main in England after Culturing in Laboratory using a Yellow Filter Ref: AEM, T. Juhna, Et. al., 2011)

15 Legionella and Mycobacterium Grow Naturally In Distribution Systems Non-Fecal Pathogens Increasing Public Health Concern Under Consideration for Regulation (CCL3) Where do they Come from?

16 Legionella and Mycobacterium Can Enter Distribution Systems Inside FLA FLA - Free-Living Amoebae Legionella/Mycobacterium Known as ARM ARM Amoeba Resistant Microorganisms ARM Can Resist Digestion by FLA FLA Grow and Proliferate in Biofilms FLA are Host Organisms which Release ARMs Not Well Understood Yet

17 To help protect your privacy, PowerPoint prevented this external picture from being automatically downloaded. To download and display this picture, click Options in the Message Bar, and then click Enable external content. Bacteria Viability in Amoebae Viable Campylobacter jejuni inside Protozoan in Drinking Water

18 Example Viable Legionella Bacteria inside a Free Living Amoeba (FLA) Legionella Bacteria Source: EPA 2011

19 BioFilms Definition Collection of Microorganisms and Slime Secretions on a Pipe Surface Depth and Quality of Biofilm Varies Different Organisms at Different Biofilm Depths Pipe Wall Organisms More Robust than Free Floating Organisms Flushing Can be Helpful or Detrimental to Water Quality

20 More on BioFilms Microorganisms Adhere to Pipe Walls Multiply and Form Colonies when Conditions are Conducive (high temps, high phs, low disinfectant residuals, nutrients) Flow Provides Nutrients Aerobic and Anaerobic Bacteria, Protozoa, Fungi Biofilms Cause: Frictional Drag Microbiologically-Induced (MIC) Corrosion

21 Biofilm Development

22 Biofilm Composition with Depth

23 Biofilm Maturity and Complexity

24 Flushing Impacts to Water Quality Can Remove Organisms Deep in Biofilms?? Temporary Increase in HPCs How do you Mitigate Impacts? Increase Chlorination Test Before and After Conclusion: Flushing is Beneficial Impacts can be Managed

25 Agitation of Biofilms

26 What Can You Do as a Water Utility? Is Your System Susceptible to Biofilm Growth? Evaluate Disinfection Practices in Your Distribution System Unidirectional Flushing Institute Practices that Discourage Biofilm Growth Manage and Reduce Water Age Modifications to Storage Tanks Consider Disinfectant Concentration

27 What Does the Future Hold? Expect More Biofilm Research Emerging Microbial Contaminants New Regulations Changes in Disinfection Practices? Management of Nutrients into Distribution Systems New Emphasis on Distribution Water Quality

28 Questions and Comments Thank you