Water safe to drink despite taste concerns

Council adjusts treatment processes to improve taste

Wednesday 18 November, 2020

The Tweed's reticulated water is safe to drink despite recent concerns that it tastes 'earthy'.

Tweed Shire Council treats its raw water supply to remove taste and odour compounds, called Geosmin and Methylisoborneol (MIB), which occur naturally and dissolve in water.

Over the past five days, Tweed Laboratory Centre tests have shown that these taste and odour compounds have increased fivefold in the Bray Park Weir pool, where the bulk of the Tweed's reticulated supply is drawn. They are most likely a result of ongoing blue-green algal blooms in the Tweed River, including at the weir pool.

Human noses and tastebuds can detect Geosmin and MIB at very low concentrations. 

"In hot dry weather, the situation with algae can change within hours requiring us to constantly tweak our water treatment processes to remove the taste and odour compounds produced by the algae," Manager Water and Wastewater Operations Brie Jowett said.

"While we have again made adjustments to our processes, the water currently in the reticulation network will have to work its way through the system before things improve. 

"The water is perfectly safe to drink despite the musty taste and odour."

The first blue-green algal bloom of the season was recorded in Clarrie Hall Dam in late August. Since then, there have been ongoing blooms in both the dam and the Tweed River moving between green and amber alerts along with changes in the weather.

In early November after some rain, flows in the Tweed River improved reducing algae levels and the water treatment processes were dialled down as the blooms dissipated.

"But in the past five days the taste and odour compounds caused by algae in the raw water have increased more than fivefold and we now have to dial up our treatment processes," she said.

Mrs Jowett urged Tweed residents connected to the reticulated water supply to be patient as the water worked its way through the system and urged caution before investing in any costly water filtration unit.

"Think of our water treatment plants as giant water filtration systems. Our water treatment plants remove both pathogens and taste and odour compounds, whereas bench-top systems sometimes only do one or the other."

Council is continuing to test the raw water at Bray Park Weir, Uki and Tyalgum and adjust its treatment processes accordingly to manage ongoing algal blooms and taste and odour issues.

For the latest, visit tweed.nsw.gov.au/WaterAndWastewater