Australian Drinking Water Map

2020/21: Calen (Qld) – E.coli.
 
2020/21: Calen Treated (Qld) – E.coli 49MPN/100mL (max), 4 MPN/100mL (mean)
 
December 7 2021: E. coli was detected in a routine sample collected from the Calen treated water sample point. Samples  collected on the following day and from reticulation sample points detected no E. coli. Low chlorine levels  were detected in the original sample. The plant only typically operates during the night, therefore, in order to collect samples it is run in manual mode. In field testing identified that when Bore 2 was operated in manual mode, or when regenerations occurred, chlorine dosing did not always occur. When the Calen reservoir was full, chlorine dosing was not occurring during the regeneration cycle. This could explain
the low free chlorine readings recorded that were recorded at the treatment plant, and not throughout the reticulation system. During the regenerations, chlorine levels in the treated water are elevated as the chlorine dosing rate is constant but the flow rate to distribution is reduced. If the Calen reservoir is full, chlorine dosing will be suspended during the regeneration period. The regeneration cycle typically occurs once a week for a period of 90 minutes. A review of the Calen Water Treatment Plant operational code identified that along with the conflict in the code when pump 2 was run in manual mode, there were other errors in the code which may cause issues with chlorine dosing when the raw water tanks were in operation. Amendments to the code have been made
 
E.coli
 
 

“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

Calen (Qld)  Hardness

2020/21: Calen Reticulation (Qld) – Hardness 262.41mg/L (max), 158.99mg/L (min)

2020/21: Calen Treated (Qld) – Hardness 259.42mg/L (max), 157.85mg/L (min)

GUIDELINE

“To minimise undesirable build‑up of scale in hot water systems, total hardness (as calcium
carbonate) in drinking water should not exceed 200 mg/L.

Hard water requires more soap than soft water to obtain a lather. It can also cause scale to form on hot water pipes and fittings. Hardness is caused primarily by the presence of calcium and magnesium ions, although other cations such as strontium, iron, manganese and barium can also contribute.”

Australian Drinking Water Guidelines 2011

 

2020/21 – Calen (Qld) – E.coli, Hardness

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2020/21: Calen (Qld) – E.coli.
2020/21: Calen Treated (Qld) – E.coli 49MPN/100mL (max), 4 MPN/100mL (mean)
December 7 2021: E. coli was detected in a routine sample collected from the Calen treated water sample point. Samples  collected on the following day and from reticulation sample points detected no E. coli. Low chlorine levels  were detected in the original sample. The plant only typically operates during the night, therefore, in order to collect samples it is run in manual mode. In field testing identified that when Bore 2 was operated in manual mode, or when regenerations occurred, chlorine dosing did not always occur. When the Calen reservoir was full, chlorine dosing was not occurring during the regeneration cycle. This could explain
the low free chlorine readings recorded that were recorded at the treatment plant, and not throughout the reticulation system. During the regenerations, chlorine levels in the treated water are elevated as the chlorine dosing rate is constant but the flow rate to distribution is reduced. If the Calen reservoir is full, chlorine dosing will be suspended during the regeneration period. The regeneration cycle typically occurs once a week for a period of 90 minutes. A review of the Calen Water Treatment Plant operational code identified that along with the conflict in the code when pump 2 was run in manual mode, there were other errors in the code which may cause issues with chlorine dosing when the raw water tanks were in operation. Amendments to the code have been made
E.coli

“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

Calen (Qld)  Hardness

2020/21: Calen Reticulation (Qld) – Hardness 262.41mg/L (max), 158.99mg/L (min)

2020/21: Calen Treated (Qld) – Hardness 259.42mg/L (max), 157.85mg/L (min)

GUIDELINE

“To minimise undesirable build‑up of scale in hot water systems, total hardness (as calcium
carbonate) in drinking water should not exceed 200 mg/L.

Hard water requires more soap than soft water to obtain a lather. It can also cause scale to form on hot water pipes and fittings. Hardness is caused primarily by the presence of calcium and magnesium ions, although other cations such as strontium, iron, manganese and barium can also contribute.”

Australian Drinking Water Guidelines 2011