2005 – Macalister River (Victoria) – Algal Bloom
Due to the ongoing algal bloom in the Macalister River System (February 2005–onwards), potable water supplies for Coongulla/Glenmaggie and Maffra were reported to experience
earthy and /or musty odours. These odours are caused by the microbial metabolites of
Geosmin, and 2-methlyisoborneol (MIB). These compounds can cause concern to the
customer as they have extremely low threshold concentrations and can persist through
conventional water treatment process. Threshold concentrations for Geosmin and MIB are
approximately 4 and 9 ng/L respectively. These compounds are generally removed by an additional process of activated carbon treatment at the water treatment. Extra monitoring
was performed to determine the total number and type of algae present in the raw water, as
well as the levels of the taste and odour compounds to determine the level of risk to the
water supply.
2006/7 – Lake Glenmaggie/Macalister River (Victoria) – Algal Bloom
Ongoing monitoring for the odour causing microbial metabolites Geosmin and 2-
methylisoborneol (MIB) was performed during the period February 2006 to January 2007 in
the towns of Maffra, Coongulla and Glenmaggie due to an ongoing algal bloom experienced
in Lake Glenmaggie and the Macalister River. These compounds had been a concern for
Gippsland Water in the previous year and were removed by an additional process of
activated carbon treatment at the water treatment plants.