Young scientist seeks answers to unusual water tastes and smells

Scientists collaborate to seek answers on biogenic effects

Why does your drinking water sometimes taste or smell a bit unusual but at other times is fine? The water is treated and safe to drink, but an usual taste or odour may remain.

A young scientist is working closely with WaterNSW and Sydney Water to help uncover the answers.

UNSW PhD student Jin Zhu is researching ‘biogenic’ tastes and odours which are caused by algae and other microorganisms. Her work was shortlisted for a prestigious 2024 NSW Water Award.

Water utilities around the world are trying to work out how to deal with these biogenic tastes and odours as they become more common due to the combined effects of climate change and more nutrients accumulating in reservoirs.

In Sydney it’s even trickier to identify the cause as water treated at Prospect comes from many sources – not just Warragamba Dam but the Upper Nepean dams of Cataract, Cordeaux, Avon and Nepean, as well as Prospect Reservoir itself.

To address this gap, WaterNSW, which manages Warragamba Dam and multiple reservoirs supplying Sydney’s drinking water, developed a proposal and enlisted UNSW to collaborate on this research.

Jin Zhu has been working with Dr Lisa Hamilton, WaterNSW Strategic Research and Innovation Manager, and Kaye Power, Sydney Water Principal Public Health Advisor, researching taste and odour causes in the Prospect Reservoir supply system.

Prospect raw water supply has higher complexity and uncertainty due to the mixing of odorants and odour-producing algae from many reservoirs.

There are currently limited tools to identify, track and manage odour issues from source water, through treatment processes and to consumers.

The project took a multidisciplinary approach integrating biochemistry, water treatment technologies and statistical analysis.

The research outcomes will help water utilities around Australia to develop improved ways to identify odorants, define thresholds for early detection of odour development, and implement proactive odour management in drinking water supplies.

UNSW researchers on dam wall
At Warragamba Dam (from left) UNSW PhD students Jin Zhu and Johnson Wong, their UNSW academic supervisors Richard Stuetz and Bojan Tamburic, and the students’ industry supervisors Lisa Hamilton (WaterNSW) and Kaye Power (Sydney Water).
Warragamba Dam wall and Lake Burragorang
Warragamba Dam supplies about 80% of the drinking water for the 5 million people of Greater Sydney. Water flows by gravity into two pipelines that supply Sydney Water's Prospect water filtration plant.

Researching the health of Sydney’s drinking water catchment

“WaterNSW undertakes research on the health of the Sydney drinking water catchment, to help us manage and protect water quality for the 5 million people of Greater Sydney,” WaterNSW Executive Manager, Strategy & Performance, Fiona Smith, said.

“Our scientific research priorities focus on understanding how catchment health and water quality work together to ensure a safe drinking water supply,” Fiona said.

“Integrated water management is our other main research priority – understanding how environmental and supply change impacts water quality and quantity, and how we can improve water quantity without compromising water quality.”

WaterNSW joint research was a shortlisted finalist in two categories at the 2024 Australian Water Association NSW Water Awards – R&D Excellence Award, and Student Water Prize.

“These awards recognise outstanding achievements of innovation in the water sector,” Fiona said. “We are delighted some of our many important research projects have been recognised in this way.”

Jin Zhu, a final-year PhD student in the School of Civil and Environmental Engineering at UNSW supervised by Dr Bojan Tamburic, was a finalist for the Student Water Prize for a joint research project with WaterNSW and Sydney Water – ‘Biogenic Taste and Odour in Drinking Water’.

WaterNSW and the UNSW Water Research Laboratory won the R&D Excellence Award for Upland Peat Swamps of the ‘Woronora Plateau – Hydrological Monitoring and Water Balance Modelling’.

Prospect Reservoir dam wall
Prospect Reservoir was Australia’s first earth fill and rock embankment dam when it was completed in 1880. Located 35km west of the CBD, the reservoir is still an important part of Sydney’s water supply system.
Cataract Dam
The Upper Nepean dams of Cataract (pictured), Cordeaux, Avon and Nepean supply up to 20% of Sydney’s drinking water. Water flows by gravity along the Upper Canal to Prospect Reservoir where it is treated by Sydney Water for supply to customers.

Related links

Managing dams and reservoirs

In the flow

Published date: 4 March 2024

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