Wangaratta (Victoria) E.coli
11/11/10- < 24hr Wangaratta (Cox rd tank) E.coli :1org/100mL Investigations could not identify the source.Chlorine residuals were increased. Resample was clear.
22/03/11 Wangaratta (Omaru Rd tank) E.coli :>200orgs/mL Initial inspection of the tank could not identify a contamination source, however vigilance was escalated when resample was also positive (24/3). Despite not identifying a specific contamination source, a series of actions were undertaken (including cleaning of the tank, relocation of the sample site tap, fix flashing around roof of tank) to mitigate further contamination risk. Residual disinfection was present. Further resample was clear.
24/03/11 Wangaratta (Omaru Rd tank) E.coli : 18 orgs/100mL
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
Wangaratta – Victoria – Turbidity
2010/11: Wangaratta Turbidity 6.5NTU (max)
2015/16 Wangaratta Turbidity 5.9NTU (max)
2016/17 Wangaratta Turbidity 5.9NTU (max)
2018/19 Wangaratta Turbidity 7NTU (max), 1.2NTU (av.)
Bushfires: In late February 2013, over 100 mm of rain fell at the head of the catchment over a short period which caused land slips and a major dirty water event. Turbidity levels of >30,000 NTU were recorded at the Bright offtake and >3,000 NTU a few days later at Wangaratta.
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.
Wangaratta – Victoria – Iron
2015/16: Wangaratta Iron 0.45mg/L
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
https://newater.com.au/Portals/0/NE-Water/Sections/What-we-do/Water/PFAS-test-results/PFAS-Drinking-Water-Quality-Report-March-2018.pdf
PFHxS + PFOS
4 samples for month
3 samples <ADWG guideline level for month
Six samples over last 6 months
Results < ADWG guideline level over last 12 months 83%
Per- and poly-fluoroalkyl substances (PFAS) are manufactured chemicals that do not occur naturally in the environment. PFAS chemicals include perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA) and perfluorohexane sulfonate (PFHxS) amongst a large group of other compounds. PFAS are persistent in the environment, show the potential for bioaccumulation and biomagnification, and are toxic in animal studies (potential developmental, reproductive and systemic toxicity). Due to PFAS water and heat resistance, they have been used in a wide range of consumer products including surface treatments such as non-stick cookware, and notably in aqueous film forming foam used to extinguish fires. While the import of some PFAS in Australia has been reduced since 2002 (Environmental Health Standing Committee, 2017), historical use in firefighting foams has resulted in detections of PFAS at a number of sites including airports, firefighting training facilities and federal government sites. PFAS has also been found in groundwater, surface water, sewage treatment plant effluents and landfill leachates in international studies (Ahrens et al., 2016; Banzhaf et al., 2017). (ADWG)
2022/23 – Wangaratta (Victoria) – Chlorine
2022/23: Wangaratta (Victoria). Chlorine 5.5mg/L (max), 0.93mg/L (mean)
GENERAL DESCRIPTION
Chlorine dissociates in water to form free chlorine, which consists of aqueous molecular chlorine, hypochlorous acid and hypochlorite ion. Chlorine and hypochlorites are toxic to microorganisms and are used extensively as disinfectants for drinking water supplies. Chlorine is also used to disinfect sewage and wastewater, swimming pool water, in-plant supplies, and industrial cooling water.
Chlorine has an odour threshold in drinking water of about 0.6 mg/L, but some people are particularly sensitive and can detect amounts as low as 0.2 mg/L. Water authorities may need to exceed the odour threshold value of 0.6 mg/L in order to maintain an effective disinfectant residual.
In the food industry, chlorine and hypochlorites are used for general sanitation and for odour control. Large amounts of chlorine are used in the production of industrial and domestic disinfectants and bleaches, and it is used in the synthesis of a large range of chemical compounds.
Free chlorine reacts with ammonia and certain nitrogen compounds to form combined chlorine. With ammonia, chlorine forms chloramines (monochloramine, dichloramine and nitrogen trichloride or trichloramine) (APHA 2012). Chloramines are used for disinfection but are weaker oxidising agents than free chlorine.
Free chlorine and combined chlorine may be present simultaneously (APHA 2012). The term totalchlorine refers to the sum of free chlorine and combined chlorine present in a sample.
Chlorine (Free) ADWG Guideline: 5mg/L (Chlorine in chloraminated supplies 4.1mg/L). Chlorine dissociates in water to form free chlorine, which consists of aqueous molecular chlorine, hypochlorous acid and hypochlorite ion.
Chlorine (Total) ADWG Guideline 5mg/L (chloraminated supplies 4.1mg/L): The term total chlorine refers to the sum of free chlorine and combined chlorine present in a sample