2016 March – Sparkes Hill Reservoir 2 (Queensland) – E.coli

Sparkes Hill Reservoir 2 (Queensland): E.coli
Sparkes Hill Reservoir 2, Brisbane (E.coli 1 MPN/100 mL, 24/03/2016). This non-routine sample was collected from the reservoir hatch in response to a detection of E.coli in the downstream distribution system. Chlorine levels were low in this chloraminated system at the time of sampling with Total Chlorine 0.37 mg/L. Seqwater confirmed that there were no operational issues through reservoir inspections and extensive follow up sampling on the reservoir inlet, outlet and nearby Aspley Reservoir. The system was also operated to increase chlorine levels to 1.5- 2.0 mg/L through the blending of water supplied from North Pine WTP. Further testing confirmed that that normal chlorine levels in the system were restored…

“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