Tallangatta (Victoria) – Turbidity
17/10/10–19/10/10 Tallangatta Dirty Water – elevated turbidity in reticulation (~8NTU)
Heavy rainfall resulted in increased turbidity in Lake Hume at Tallangatta. Despite instrumentation shutting down the WTP, a slug of dirty water passed through the filters and entered the CWS. The turbid water was not identified by operational staff until it began to supply the reticulation. Once identified, the bulk of the turbid water was able to be flushed from the reticulation within a few hours. Additional monitoring was also undertaken.
As similarities and timing of both dirty water events coincided, similar long term actions were implemented. Additionally, checks of CWS water quality is linked to incident
response procedures were implemented.
18/02/11-approx. 2 months Tallangatta Widespread public complaint Due to rise in Lake Hume, high algal presence caused Taste and Odour compounds to be present in the drinking water. This caused widespread public complaint. Powdered Activated Carbon dosing was initiated, however took time to optimise. Further monitoring and improved operations at the plant reduced the levels of the T&O compounds.
“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.”