Blue-green algae alert at Bray Park Weir climbs to amber

25 November 2020

Tweed Shire reticulated water safe to drink

The Tweed’s treated water remains safe to drink despite the blue-green algae alert for Bray Park Weir rising to amber.

Algae alerts have been current for the weir pool, where the bulk of the Tweed’s water is drawn for treatment, since early September moving between green and amber alert levels.

Light rain in mid-October increased flows in the Tweed River partially flushing the weir pool and downgrading the then amber alert to green. But, with no follow-up rain and increasingly hot temperatures algal growth has again been stimulated in the weir pool.

Council has adjusted its water treatment processes at Bray Park Water Treatment Plant to deal with the amber alert by dosing the water with powder activated carbon (PAC). The algae and any potential toxin, together with any taste and odour compounds, binds to the carbon’s surface and is filtered out using membrane ultrafiltration technology.

“The membrane barrier consists of hollow plastic fibres with billions of microscopic pores thousands of times smaller than a human hair. It removes suspended solids, bacteria, particle-bonded viruses and parasites,” Manager Water and Wastewater Operations Brie Jowett said.

“Our use of PAC also has removed the earthy taste and odour compounds we experienced last week and the Tweed’s drinking water is again tasting and smelling pleasant.”

Two of Council’s three treatment plants at Bray Park and Tyalgum use membrane ultrafiltration technology. The Uki plant also is capable of removing taste and odour compounds.

Council is routinely monitoring the algae levels in all raw water sources and adjusting its water treatment processes as required.

“While this hot, dry weather continues we can expect to be in this ongoing monitoring and treatment adjustment phase,” she said.

Blue-green algae occur naturally and can reproduce quickly in favourable environmental conditions, such as where there is still or slow-flowing water, abundant sunlight and warm weather as well as sufficient levels of nutrients.

Affected water appears to have a green paint-like scum on the water, near the edges, or greenish clumps throughout the water.

Anyone who thinks they may have been in contact with blue-green algal water is advised to seek medical advice if symptoms appear.

For the latest, visit Council's website tweed.nsw.gov.au/WaterAndWastewater

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Caption: The blue-green algae alert at Bray Park Weir has been upgraded to amber.