2008 December – Frankston South – Armagh Road (Victoria) – E.coli

Frankston South  – (Victoria) – E.coli

The second E.coli detection was from a sample tap located on an outlet main at the Armagh Road Basin Outlet, in the Frankston South locality, on 3 December 2008 (one E.coli organism per 100mL) with a free chlorine residual of 0.01 mg/L. The Armagh Road Basin is supplied from Humphries Road which is fed from Cardinia Reservoir via the South Frankston Chlorinator. Re-samples were taken from Armagh Road Basin and the reticulation system. Two of these samples were positive for E.coli, thefirst at Armagh Road Basin (one E.coli organism per
100mL) and the other within the reticulation system (two E.coli organisms per 100mL). An incident was immediately declared by South East Water and the Armagh Road Basin taken off-line. Operational adjustments undertaken during the incident included increasing chlorination at South Frankston, changing supplies into the locality, dosing of tanks and basins in the Frankston South locality and flushing of the reticulation system. It was determined that the most likely source of the E.coli was a hole in the floating cover of Armagh Road Basin. Following

operational changes, re-samples taken within the reticulation system were clear of E.coli. Armagh Road Basin remained off-line for a number of weeks, during which time the basin was drained and the cover repaired. Prior to returning Armagh Road Basin back to operation, the basin was sampled and found to be clear ofE.coli. A permanent secondary disinfection plant was installed on the pumped inlet pipeline to Armagh Road Basin to maintain residuals within the basin and reticulation system.


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