E.Coli with a level of 71CFMU was detected at the Council office on 29/06/16.
It was suspected that that the sample water was contaminated, since E.Coli was not detected at other sites. There were also reported issues with the PaCl dosing at the WTP which were reported as a potential cause. Further follow up investigations in December revealed that water was being samped from property tanks rather than the mains, because the mains water was typically only turned on 1 day per week to fill the tanks. This incorrect procedure was corrected while the desal plant was operating, because this was constantly pumping water into the mains.
The Boil Water Alert at Erub was removed on 26/08/16
“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