place. Retests were clear.
Retests were clear .
7/07/09 Tawonga E. coli Hypo-chlorinated tank. Resample was clear.
11/01/10 Tawonga Enterococcus detection 1org/100mL each at Tawonga and Tawonga South reticulation Confirmed Ozone Plant was operating satisfactorily and ongoing monitoring in place. No cause for sporadic contamination could be found. Chlorine dosing due for implementation by mid February.
1/02/10 Tawonga Enterococcus detection 1org/100mL
8/02/10 Tawonga E. coli detection 1org/100mL at Tawonga South WTP
15/03/10 to 29/03/10 Tawonga Various Enterococcus detections at Ranch Rd Tank Disinfection with chlorine was initiated at the Mt. Beauty Water Treatment Plant on Tuesday 16 March 2010. Mains were flushed 22-24 March to remove biofilm and increase the chlorine residuals to the area.
“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
Tawonga (Victoria) – Campylobacter
system in Tawonga.
possible presence of pathogenic Campylobacter. If explicitly sought, Campylobacter spp
should not be detected. If detected, advice should be sought from the relevant health authority.
Thermophilic Campylobacter spp are transmitted by the oral route, and cause gastrointestinal illness. Wild birds and poultry are the most important reservoirs of Campylobacter. Other domestic animals, such as pigs, cattle, dogs and cats, are also reservoirs of thermophilic Campylobacter organisms, and so meat, and particularly poultry products and unpasteurised milk, are important sources of Campylobacter infection. Milk may be contaminated with faeces or by secretion of organisms into the milk of cows with mastitis. Recent studies have shown that raw sewage frequently contains from 10 to 105 thermophilic Campylobacter organisms per 100 mL; high counts can be reduced by wastewater treatment processes. Thermophilic campylobacters have been found in crude sewage sludge, but were not detectable in digested conditioned sludge or filter effluent. Their occurrence in surface waters is dependent on rainfall,
water temperature and the presence of water fowl.
detected in drinking water, immediate action should be taken, including investigation of
potential sources of faecal contamination.
Intestinal enterococci are a functional group of organisms from the Enterococcus and Streptococcus genera that are excreted in human and animal waste. Species include Enterococcus faecalis, E. faecium, E. durans, E. hirae, E. cecorum, E. columbae, E. avium and E. gallinarum together with Streptococcus bovis and S. equinus (ISO 1998, Ashbolt et al. 2001, WHO 2003). Use of the terms intestinal enterococci, faecal streptococci, enterococci and streptococci has been a source of some confusion. This has been exacerbated by revisions of taxonomy. The older taxonomy described faecal streptococci as a subgroup of the genus Streptococcus. The group including S. faecalis, S. faecium, S. bovis, S. equinus, S. avium, and S. gallinarum all possess the Lancefield group D antigen. The enterococci S. faecalis,
S. faecium, S .avium and S. gallinarum represented a smaller subgroup of the faecal streptococci, which was differentiated by an ability to grow in 6.5% sodium chloride, at pH 9.6 and at both 10oC and 45oC (APHA et al. 2005). The nomenclature of this subgroup has been changed and they are now identified as Enterococcus spp: E. faecalis, E. faecium, E. avium and E. gallinarum (LeClerc et al. 1996). These species are principal members of the intestinal enterococci, together with other enterococci of faecal origin. The similar membership of the various groups means that tests for intestinal enterococci, faecal streptococci, enterococci and streptococci often provide the same results.
SOURCE AND OCCURRENCE
Intestinal enterococci are excreted in the faeces of humans and other warm-blooded animals, including livestock, domestic animals and birds (Ashbolt et al. 2001). Most species do not grow in water but the standard test for intestinal enterococci can detect environmental species such as E. casseliflavus and E. mundtii (ISO 1998). Intestinal enterococci are present in large numbers in sewage and can be present in water environments polluted by sewage or wastes from humans and animals.
Tawonga (Victoria) – Cryptosporidium
2008/9: Four positive cryptosporidium results were detected in the reticulation in Corryong High Level, Corryong Low Level, Myrtleford and Tawonga. Each of these localities is unfiltered and Myrtleford and Tawonga do not have residual disinfection. Investigations into these detections did not reveal the source of the detection. North East Water Annual Drinking Water Quality Report 2008/9
“In recent years, Cryptosporidium has come to be regarded as one of the most important waterborne human pathogens in developed countries. Over 30 outbreaks associated with drinking water have beenreported in North America and Britain, with the largest infecting an estimated 403,000 people (Mackenzieet al. 1994). Recent research has led to improved methods for testing water for the presence of humaninfectious species, although such tests remain technically demanding and relatively expensive.
Cryptosporidium is an obligate parasite with a complex life cycle that involves intracellular development in the gut wall, with sexual and asexual reproduction. Thick-walled oocysts, shed in faeces are responsible for transmission. Concentrations of oocysts as high as 14,000 per litre in raw sewage and 5,800 per litre in surface water have been reported (Madore et al. 1987). Oocysts are robust and can survive for weeks to months in fresh water under cold conditions (King and Monis 2007).
There are a number of species of Cryptosporidium, with C. hominis and C. parvum identified as the main causes of disease (cryptosporidiosis) in humans. C. hominis appears to be confined to human hosts, while the C. parvum strains that infect humans also occur in cattle and sheep. C. parvum infection sare particularly common in young animals, and it has been reported that infected calves can excrete up to 10 billion oocysts in one day. Waterborne outbreaks of cryptosporidiosis have been attributed to inadequate or faulty treatment and contamination by human or livestock (particularly cattle) waste.
C. hominis and C. parvum can be distinguished from one another and from other Cryptosporidium species by a number of genotyping methods. Infectivity tests using cell culture techniques have also been developed. Consumption of contaminated drinking water is only one of several mechanisms by which transmission (faecal-oral) can occur. Recreational waters, including swimming pools, are an important source of cryptosporidiosis and direct contact with a human carrier is also a common route of transmission.Transmission of Cryptosporidium can also occur by contact with infected farm animals, and occasionally through contaminated food.” ADWG 2011
Tawonga (Victoria) – Turbidity
2013/14: Tawonga/Tawonga South Turbidity 24NTU (max)
2019/20: Tawonga/Tawonga South Turbidity 8.2NTU (max)
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