2018 February Chinchilla (Queensland) – E.coli

Boil drinking water at Chinchilla

https://www.dalbyherald.com.au/news/boil-drinking-water-at-chinchilla/3346393/

CHINCHILLA residents will need to boil their drinking water for at least three days, after the council issued a warning yesterday afternoon.

A rise in E. Coli levels triggered the boil-water notice.

E. Coli is a bacterium which can make people sick however most strains are harmless.

The rise in levels was blamed on heavy rainfall in the area, which collected the bacteria in its run-off, Mayor Paul McVeigh said.

“We discovered yesterday elevated levels of E. Coli (and) what we have done is immediately raised the levels of chlorine in the water,” Cr McVeigh said.

This is the third boil-water notice the council has issued since November.

On November 4, Condamine residents were told to boil water. That notice was lifted 11 days later.

Last month, Miles residents had to boil drinking water after quality issues were discovered at the town water treatment plant.

Cr McVeigh said there had been a “run” of issues in Western Downs communities but stated the council was doing a good job detecting problems.

Reaction to the announcement on social media was less than positive, with many frustrated at another such notice.

Many on the council Facebook paged questioned how the water quality could be classified as undrinkable, less than a year after the completion of the multi-million dollar upgrade of the Chinchilla water treatment plant.

The water is expected to be given the all-clear to drink by Queensland Health in the next three days.

2017/18 – Chinchilla (Queensland) – E.coli

2017/18: Chinchilla (Queensland) 15/239 samples non-compliant for 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

2013/17 – Chinchilla (Queensland) Trihalomethanes

2015 April: Chinchilla (Queensland) Trihalomethanes ~380μg/L (av 2013/17 ~190μg/L)

Trihalomethanes Australian Guideline Level 250μg/L (0.25mg/L)

Why and how are THMs formed?
“When chlorine is added to water with organic material, such as algae, river weeds, and decaying leaves, THMs are formed. Residual chlorine molecules react with this harmless organic material to form a group of chlorinated chemical compounds, THMs. They are tasteless and odourless, but harmful and potentially toxic. The quantity of by-products formed is determined by several factors, such as the amount and type of organic material present in water, temperature, pH, chlorine dosage, contact time available for chlorine, and bromide concentration in the water. The organic matter in water mainly consists of a) humic substance, which is the organic portion of soil that remains after prolonged microbial decomposition formed by the decay of leaves, wood, and other vegetable matter; and b) fulvic acid, which is a water soluble substance of low molecular weight that is derived from humus”. US EPA

2015/16 – Chinchilla (Queensland) – pH (alkaline)

2015/16 – Chinchilla (Queensland) – pH 8.53 (av. 2015/16)

Based on the need to reduce corrosion and encrustation in pipes and fittings, the pH of
drinking water should be between 6.5 and 8.5.

New concrete tanks and cement-mortar lined pipes can significantly increase pH and
a value up to 9.2 may be tolerated, provided monitoring indicates no deterioration in
microbiological quality.

pH is a measure of the hydrogen ion concentration of water. It is measured on a logarithmic scale from 0 to 14. A pH of 7 is neutral, greater than 7 is alkaline, and less than 7 is acidic.

One of the major objectives in controlling pH is to minimise corrosion and encrustation in pipes and fittings. Corrosion can be reduced by the formation of a protective layer of calcium carbonate on the inside of the pipe or fitting, and the formation of this layer is affected by pH, temperature, the availability of calcium (hardness) and carbon dioxide. If the water is too alkaline (above pH 8.5), the rapid deposition and build-up of calcium carbonate that can result may eventually block the pipe.