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

Clunes (Victoria) – Bromate

2009/10: Clunes (Victoria) – Bromate 0.02mg/L.

In 2010/11: the highest Bromate level in Victoria was detected at Clunes – Central Highlands Water 0.03mg/L.

4 August 2011 (41 days) Clunes Customer Tap Bromate – 0.03 mg/L Clunes Reticulation

2013/14: Clunes Customer Tap Bromate – 0.02 mg/L

5/8/21 : Clunes (customers tap) Bromate 0.03mg/L (max). Informed DH. Exceedence occurred during a short treatment trial of an existing back-up bore, to ensure it can be successfully utilised over summer periods, as a contingency option. The different water chemistry in this back-up bore, together with the ozone dose applied during the trial, causeda slight elevation in bromate formation for a portion of the ~3 week trial period. Thorough investigations were conducted, in conjunction with the treatment contractor. Information was gathered to inform future treatment conditions of back- up source water (if required) in terms of optimising ozone
dosing while assessing impacts on sulphide/manganese removal capability and THM formation potential. Bromate levels reduced to historic levels once the treatment trial was complete, and the usual water source was reintroduced.

Bromate: Regulatory Standard = 0.02mg/L (Also see section of desalination). A suspected carcinogen. Bromate is formed when ozone used to disinfect drinking water reacts with naturally occurring bromide found in source water. Bromate formation in disinfected drinking water is influenced by factors such as bromide ion concentration, pH of the source water, the amount of ozone and the reaction time used to disinfect the water.

Clunes (Victoria) – Trihalomethanes

2015/16: Clunes Trihalomethanes 240ug/L

2019/20: Clunes Trihalomethanes 240ug/L (max) 149ug/L (av.)

Trihalomethanes Australian Guideline Level 250μg/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

Clunes –  Victoria – Iron

2009/10: Clunes (Victoria)  – Iron 0.46mg/L (Highest level only)

Based on aesthetic considerations (precipitation of iron from solution and taste),
the concentration of iron in drinking water should not exceed 0.3 mg/L.
No health-based guideline value has been set for iron.

Iron has a taste threshold of about 0.3 mg/L in water, and becomes objectionable above 3 mg/L. High iron concentrations give water an undesirable rust-brown appearance and can cause staining of laundry and plumbing fittings, fouling of ion-exchange softeners, and blockages in irrigation systems. Growths of iron bacteria, which concentrate iron, may cause taste and odour problems and lead to pipe restrictions, blockages and corrosion. ADWG 2011