2015/20 – Mathinna (Tasmania) – E.coli, Colour, Temperature, Turbidity, Haloacetic Acids

BOIL WATER ALERT

Mathinna (Tasmania) – E.coli

July 21 2015: Mathinna (Tasmania) Regatta Point – 1 MPN100/mL

August 18 2015: Mathinna (Tasmania) Regatta Point – 2 MPN100/mL

September 15 2015: Mathinna (Tasmania) Regatta Point – 5.2 MPN100/mL

January 19 2016: Mathinna (Tasmania) Regatta Point – 6.3 MPN100/mL

May 17 2016: Mathinna (Tasmania) Regatta Point – 4.1 MPN100/mL

June 21 2016: Mathinna (Tasmania) Regatta Point – 2 MPN100/mL

2016/17: 10 E.coli exceedences. Poor microbiological performance can be attributed to a lack of barriers and the susceptibility to changes in quality from the South Esk River. The risk to public health is mitigated through the communication of the Permanent BWA to customers.

19/9/2017: Mathinna (Tasmania) E.coli of 1 MPN/100mL in monthly compliance sample. System subject to PHA.

17/10/17: Mathinna E.coli of 11 MPN/100mL in monthly compliance sample. System subject to PHA.

15/11/17: Mathinna E.coli of 2 MPN/100mL in monthly compliance sample. System subject to PHA.

20/2/18: Mathinna E.coli of 3.1 MPN/100mL in monthly compliance sample. System subject to PHA.

20/3/18: Mathinna E.coli of 3.1 MPN/100mL in monthly compliance sample. System subject to PHA.

17/4/18: Mathinna E.coli of 9.8 MPN/100mL in monthly compliance sample. System subject to PHA.

Escherichia coli should not be detected in any 100 mL sample of drinking water. If detected
in drinking water, immediate action should be taken including investigation of potential
sources of faecal contamination.

“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

Mathinna –  (Tasmania) – Colour

August 20 2015: Mathinna (Tasmania) – Colour Apparent 38 PCU

November 30 2015: Mathinna (Tasmania) – Colour Apparent 21 PCU

March 8 2016: Mathinna (Tasmania) – Colour Apparent 34 PCU

June 8 2016: Mathinna (Tasmania) – Colour Apparent 73 PCU

2016/17: Mathinna (Tasmania) – Colour 41 HU (max), 28.5 HU (mean)

2017/18: Mathinna (Tasmania) – Colour 28 HU

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…

Mathinna – Tasmania – Temperature

February 23 2016: Cressy (Tasmania) – Temperature 20.4C

GUIDELINE

“No guideline is set due to the impracticality of controlling water temperature.
Drinking water temperatures above 20°C may result in an increase in the number of
complaints.

Temperature is primarily an aesthetic criterion for drinking water. Generally, cool water is more palatable than warm or cold water. In general, consumers will react to a change in water temperature. Complaints are most frequent when the temperature suddenly increases.

The turbidity and colour of filtered water may be indirectly affected by temperature, as low water temperatures tend to decrease the efficiency of water treatment processes by, for instance, affecting floc formation rates and sedimentation efficiency.

Chemical reaction rates increase with temperature, and this can lead to greater corrosion of pipes and fittings in closed systems. Scale formation in hard waters will also be greater at higher temperatures…

Water temperatures in major Australian reticulated supplies range from 10°C to 30°C. In some long, above-ground pipelines, water temperatures up to 45°C may be experienced…

The effectiveness of chlorine as a disinfectant is influenced by the temperature of the water being dosed. Generally higher temperatures result in more effective disinfection at a particular chlorine dose, but this may be counterbalanced by a more rapid loss of chlorine to the atmosphere (AWWA 1990).

Mathinna (Tasmania) – Turbidity

2016/17: Mathinna (Tasmania) – Turbidity 26.3 NTU (max), 4.43 NTU (mean)

Chlorine-resistant pathogen reduction: Where filtration alone is used as the water treatment
process to address identified risks from Cryptosporidium and Giardia, it is essential
that filtration is optimised and consequently the target for the turbidity of water leaving
individual filters should be less than 0.2 NTU, and should not exceed 0.5 NTU at any time
Disinfection: A turbidity of less than 1 NTU is desirable at the time of disinfection with
chlorine unless a higher value can be validated in a specific context.

Aesthetic: Based on aesthetic considerations, the turbidity should not exceed 5 NTU at the
consumer’s tap

Mathinna (Tasmania) – HAA’s

14/8/19: Mathinna (Tasmania) Total Haloacetic Acid (HAA7): 128ug/L

6/11/20: Mathinna (Tasmania) Total Haloacetic Acid (HAA7): 171ug/L

Australian Guidelines Trichloroacetic Acid 0.100mg/L, Dichloroacetic Acid 0.100mg/L

“Chloroacetic acids are produced in drinking water as by-products of the reaction between chlorine and naturally occurring humic and fulvic acids. Concentrations reported overseas range up to 0.16mg/L and are typically about half the chloroform concentration. The chloroacetic acids are used commercially as reagents or intermediates in the preparation of a wide variety of chemicals. Monochloroacetic acid can be used as a pre-emergent herbicide, dichloroacetic acid as an ingredient in some pharmaceutical products, and trichloroacetic acid as a herbicide, soil sterilant and antiseptic.” Australian Drinking Water Guidelines – National Health and Medical Research Council…