Harkaway – King Rd – Victoria – E.coli
The eleventh event was a detection of E. coli from a routine sample taken on 5 February 2010 at King Road Tank, Harkaway, (five E. coli organisms per 100 mL) with a free chlorine residual of 0.03 mg/L. The tank, which is located within the Berwick locality, is supplied by Cardinia Reservoir. The tank was immediately isolated, inspected and dosed to a free chlorine residual of
0.5 mg/L. The resamples taken at the reservoir and two taps within the reticulation system were clear of E. coli. The tank was thoroughly inspected and it was determined that it should be drained and cleaned, with adjustments made to the roofing to prevent any further rain from
entering the tank.
The fifteenth event was a detection of E. coli from a routine sample taken on 9 June 2010 at King Road Tank, Harkaway, (one E. coli organism per 100 mL) with a free chlorine residual of
0.28 mg/L. The tank, which is located within the Berwick locality, is supplied by Cardinia Reservoir. The tank was immediately isolated, inspected, flushed and dosed to a free chlorine
residual of 0.5 mg/L. All system checks were clear and resamples taken at the tank and another tap within the reticulation system were clear of E. coli. As the supply area from this tank is only approximately 25 properties, it was decided to make system augmentations to ensure the tank has a higher demand. To achieve this, a bypass between the two supply zones (Narre Warren High Level and King Road Tank) has been installed to ensure that the water is constantly
being turned over through the tank.
https://southeastwater.com.au/SiteCollectionDocuments/LearnAboutWater/WaterQuality/WaterQualityReport200910.pdf
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