2010/23: Trawool (Victoria) – Chloral Hydrate, Iron, Turbidity, Colour

Trawool (Victoria) Iron

The source of iron at Trawool is from the original 1890 cast iron main in the reticulation system.

2012/13: Trawool (Victoria)  – Iron 0.41mg/L (max)

2013/14: Trawool (Victoria)  – Iron 0.65mg/L (max)

2014/15: Trawool (Victoria)  – Iron 0.65mg/L (max)

2015/16: Trawool (Victoria)  – Iron 0.61mg/L (max)

2017/18: Trawool (Victoria)  – Iron 0.62mg/L (max)

2018/19: Trawool (Victoria) – Iron 0.7mg/L (max)

2019/20: Trawool (Victoria) – Iron 2.9mg/L (max)

2020/21: Trawool (Victoria) – Iron 0.73mg/L (max)

2022/23: Trawool (Victoria) – Iron 1.4mg/L (max)

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

2014/15 – Trawool (Victoria) – Turbidity

2014/15: Trawool (Victoria) – Turbidity 7.6NTU (max).

2019/20: Trawool (Victoria) – Turbidity 8NTU (max), 1.1NTU (av) Due to the age of the Trawool main, regular flushing is undertaken while considering the life of the main..

2020/21: Trawool (Victoria) Turbidity 8.1NTU (max) 0.1 NTU (95th percentile). 2 non-complying samples

2022/23: Trawool (Victoria) Turbidity 4.8NTU (max), 3.9NTU (95th percentile)

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

2014/15 – Trawool (Victoria) – Colour

2014/15 Trawool – Colour ~35HU (highest level)

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…

Trawool  (Victoria)

Trawool 0.038mg/L Chloral Hydrate 2010/11

2004 Australian Drinking Water Guideline: Trichloroacetaldehyde (chloral hydrate): 0.02mg/L

2011 Australian Drinking Water Guideline: Trichloroacetaldehyde (chloral hydrate): 0.1mg/L

“Chloral hydrate is a disinfection by-product, arising from chlorination of water containing naturally occurring organic material (NOM). Chloral hydrate has only been detected by Goulburn Valley Water since changing to a new contract testing laboratory in November 2007. The Department of Health is currently conducting a study into the detection of chloral hydrate across Victoria.”