2009/15 – Yarrabah (Queensland) – E.coli, Colour

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2009/15 – Yarrabah – (Queensland) – E.coli

29/7/09: Yarrabah (Queensland). E. coli detections at multiple points in the reticulation. Boil Water Alert was issued. Creek was put back into use following sufficient water flow. Free chlorine levels were low. Free chlorine levels increased and E.coli testing increased to weekly frequency. Only one chlorine dose point at that time.

15/12/10: Yarrabah (Queensland). E. coli detected at the Police station. Proper flushing was not done prior to sample collection. Station can be subject to low flow and turnover which dissipates chlorine. One chlorine pump was not working, which was then changed and chlorine residual increased. Longer flushing to be also done. Only one chlorine dose point at that time.

29/3/12: Yarrabah (Queensland). E. coli detections at multiple points. Boil Water Alert issued. Fault with chlorine dosing pipe. Pipe replaced and mains flushed. Consecutive sampling showed no E. coli detections. Only one chlorine dose point at that time. Two more dose points were then subsequently installed.

18/8/15: Yarrabah (Queensland). Ran out Chlorine Hydroxide 10%, Boil Water Alert issued. Investigation report has sent to DEWS

“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

2011 – Yarrabah – (Queensland) – Colour

September 2011: Colour 29 True Colour Hazen

Based on aesthetic considerations, true colour in drinking water should not exceed 15 HU.

“… Colour is generally related to organic content, and while colour derived from natural sources such as humic and fulvic acids is not a health consideration, chlorination of such water can produce a variety of chlorinated organic compounds as by-products (see Section 6.3.2 on disinfection by-products). If the colour is high at the time of disinfection, then the water should be checked for disinfection by-products. It should be noted, however, that low colour at the time of disinfection does not necessarily mean that the concentration of disinfection by-products will be low…