April 21-24 2015: Morwell – E.coli BOIL WATER ALERT
Morwell High Level Water Reticulation. Boil Water Advisory E. coli detected in drinking water (Maximum value = 3 organisms/100mL).
Department of Health and Human Services (DHHS) Notification under section 22 SDWA.
Boil water advisory initiated on 4th day when positive low level E.coli results from sampling
were reported. Extensive flushing undertaken throughout the reticulation network and additional monitoring of water quality parameters undertaken duringand after the event.
A cross connection between untreated and treated water systems identified as the cause and was isolated as soon as located.
Boil Water Advisory initiated and in place for 3 days until additional monitoring of water quality parameters confirmed no E.coli present in drinking water supply.
Alternative water supplies provided to sensitive customers (schools, child care, aged care and hospitals). Media engaged to deploy messages (including radio, newspaper, twitter, Facebook)
All subsequent reticulation monitoring was compliant. Field activities undertaken to remove cross connection and ongoing investigations to identify and remove any additional cross connections that may exist within the drinking water supply system
November 5 2015: Morwell – E.coli
Morwell High Level Water Reticulation. Boil Water Advisory E. coli detected in drinking water (Maximum value = 2 organisms/100mL).
Human Services (DHHS) Notification under section 22 SDWA. Extensive flushing undertaken
throughout the reticulation network and additional monitoring of water quality parameters undertaken during and after the event. Additional disinfection undertaken at storage.
All subsequent reticulation monitoring was compliant. The investigation report was
submitted to DHHS, with the initial detection being determined to be a false positive, as per the Regulations (2015) Refresher training of sampling staff undertaken.
Escherichia coli should not be detected in any 100 mL sample of drinking water. If detected
in drinking water, immediate action should be taken including investigation of potential
sources of faecal contamination.
“Coliforms are Gram-negative, non-spore-forming, rod-shaped bacteria that are capable of aerobic and facultative anaerobic growth in the presence of bile salts or other surface active agents with similar growth-inhibiting properties. They are found in large numbers in the faeces of humans and other warm-blooded animals, but many species also occur in the environment.
Thermotolerant coliforms are a sub-group of coliforms that are able to grow at 44.5 ± 0.2°C. E. coli is the most common thermotolerant coliform present in faeces and is regarded as the most specific indicator of recent faecal contamination because generally it is not capable of growth in the environment. In contrast, some other thermotolerant coliforms (including strains of Klebsiella, Citrobacter and Enterobacter) are able to grow in the environment and their presence is not necessarily related to faecal contamination. While tests for thermotolerant coliforms can be simpler than for E. coli, E. coli is considered a superior indicator for detecting faecal contamination…” ADWG 2011