Water Quality Incident. Lessons Learned from a Boil Water Incident 2016

Transcription

1 Water Quality Incident Lessons Learned from a Boil Water Incident 2016

2 Drinking Water Legislation NSW Public Health Act and Regulations Australian Drinking Water Guidelines NSW Guidelines for Drinking Water Management Systems Council Drinking Water Quality Management Plan DPI Water Circular 18

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4 Background Large regional centre in NSW Positive low level e-coli detection in a regular reticulation monitoring sample Corresponded to low free chlorine residual Boil water notice issued after consultation with NSW Health

5 Incident Timetable Initial Detection Response Date 1 November to 3 November 2016 Activity Routine reticulation sample taken, result E.coli = 4 (MPN/100mL), free chlorine 0.06 L (mg/l), followed by re-test Investigation and Identification 3 November to 9 November 2016 Isolation and Treatment 10 November to 11 November 2016 Rectification and Restoration 12 November to 15 November 2016 Flushing, chlorine testing, reservoir tablet dosing and preliminary reviews of reservoirs. Liaison continued with NSW Health. Boil water notice issued at am, 7 November 2017 for Newtown and Myall zones. Isolation of Newtown Zone from the Myall Street Zone Myall Street Reservoir No 2 identified as potential source of the contamination subsequently taken off line. Boundary change issued for the boil water notice area (Myall Zone only) (on the morning AM of 10 November 2016) as Newtown zone cleared of contamination. Myall Street Reservoir No 1 isolated and chlorinated overnight and used as the active supply reservoir. Both Myall Street Reservoirs inspected and cleaned. Conference call with NSW Health held on 15 November and boil water notice lifted at 3pm. No 2 Reservoir remained off-line while further cleaning and repairs undertaken (completed 13 December 2016).

6 Overall Approach Incident Management Team formed Operations Logistics Public Relations Planning/strategy Systematic approach WTP Reservoirs reticulation Site visits, meetings, discussions with operational personnel Eliminate likely causes Ensuring Safe Drinking Water. Steve and Elizabeth Hrudey. (AWWA, p. 6)

7 Initial Response Mains replacement work Reservoirs were deemed clean but were they really? Communication was mostly well managed, 600 calls in 3 days Social media comments and questions Confusion in the media (e.coli vs e.bola) Dubbo Regional Council was aware of social media comments from angry and concerned residents this week who demanded to know (mistakenly) how the ebola (yes, ebola) virus could get into Dubbo s water supply.

8 What the Divers Found

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15 Post Incident Debrief workshop Root cause analysis Incident report

16 Root Cause Assessment Fishbone Analysis (Ishikawa diagram) Define problem micro-biological contamination of drinking water Potential causes 1. Lack of understanding of the system configuration 2. Mains replacement 3. Reservoir inspections 4. Water quality data response and management

17 Recommendations 44 recommended actions Operational management Undertake practice drills Training CCP limits and response requirements Data management more robust review and clear responsibilities Review and update previous water quality risk assessments Document system configuration, need change management process Follow emergency response procedures Improve procedures

18 Recommendations (continued) Operational Management Manage water age (eg modify system configuration for low flow periods Address resourcing shortages Develop reservoir inspection checklist and train operators in detection and escalation Ensure action identified from this investigation are captured in a Council system (eg Drinking Water Quality committee) Asset management (scheduling, recording, actions)

19 Recommendations (continued) Communication/procedures Prepare media release template, boil water notice and information for customer enquiries (eg Q & A) Better map of water quality zones needed for social media Review and update critical customers list and roles and responsibilities for who is contacted and how contact occurs (eg letters, phone calls, etc) Review BCP, other procedures and update, document responsibilities for each role

20 Recommendations (continued) Capital Works Reservoir access, security, more bird proofing, tree trimming (Myall site) Mixers in reservoirs Result Continuous improvement

21 Thank you

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