2015/16 – Heyfield (Victoria) – Blue Green Algae, Turbidity, Iron

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Heyfield – Victoria – Blue Green Algae
During the reporting period, there was one Blue Green Algae or algal blooms of concern at the Heyfield water treatment plant off stream raw water storage. An alternate source was available during this perio d whilst algal monitoring was undertaken during this period. Notification as the local storage manager occurred through Department of Environment, Land, Water and Planning (DELWP) portal as required under the DELWP Blue Green Algae Circular 2015-16
Testing of the algal bloom was undertaken, with the results indicating that the species was not producing toxins. The raw water storage basin was partially drained by storage irrigation to surrounding farmland with neighbour permission, including the implementation of exclusion/withholding period for stock. Once the algal bloom finished and algal cell numbers returned below the DELWP Blue Green Algae Circular 2015-16 limits, the Heyfield off stream raw water storage was refil led and returned to service.

 

Heyfield – Victoria – Turbidity

2015/16: Heyfield (Victoria) – Turbidity 6.5 NTU (Maximum detection during year)

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.

Heyfield – Victoria – Iron

2015/16: Heyfield (Victoria)  – Iron 0.4mg/L (Highest level only)

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