2010/11 + 2020/23: Alexandra (Victoria) – Turbidity, Iron, Chloral Hydrate

2020/21 – Alexandra (Victoria) – Turbidity

2020/21: Alexandra (Victoria) – Turbidity 5.6NTU (max), 0.1NTU (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

Alexandra (Vic) – Iron

2022/2023:  Alexandra (Vic) – Iron 0.35mg/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

Alexandra (Victoria) – Chloral Hydrate

Highest Chloral Hydrate levels recorded 2010-2011: 0.048mg/L Alexandra 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.” p55 Water Quality Annual Report Goulburn Valley Water.