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The brains behind Australia’s first groundwater replenishment scheme

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Over the past 50 years, the rainfall in Western Australia’s southwest has decreased by nearly a fifth, prompting Perth to embark on Australia’s first full-scale water recycling initiative, in an effort to shore up its future drinking water supply. Research carried out by the Curtin Water Quality Research Centre (CWQRC), in close collaboration with partners Water Corporation, GHD and Water Research Australia, was fundamental in the development of the plant.

The Beenyup Advanced Water Recycling Plant, located in the northern Perth suburb of Craigie, is the key component of Australia’s first full-scale Groundwater Replenishment Scheme.

Operated by Water Corporation – the WA Government–owned principal supplier of water, wastewater and drainage services – the plant can recharge up to 14 billion litres of recycled water into groundwater supplies in the deep Leederville and Yarragadee aquifers each year through onsite bores. It has direct impact upon much of Perth’s population of two million people, with indirect impacts on other cities nationally and internationally who are considering adopting similar technology.

Construction of Stage 1 of the plant ran from 22 October 2014 to July 2016. It required moving more than 18,000 m3 of dirt, pouring 1,000 m3 of concrete, pulling 70 km of cables and laying 15 km of pipe. The project created more than 180 construction jobs. On 14 July 2016, former WA Minister for Water Mia Davies announced the acceleration of the construction of Stage 2 to double the plant’s capacity to 28 billion litres of recycled water each year. The Stage 2 plant will be located next to Stage 1 and is currently under construction.

Water Corporation Principal Engineer for Integrated Water Cycle Planning, Palenque Blair, says groundwater replenishment is advantageous when compared with other methods.

“Producing drinking water by groundwater replenishment uses about half the amount of energy of seawater desalination. It also has environmental benefit to groundwater-dependent ecosystems, achieved by careful location of recharge and abstraction sites and additional short-term water storage in the aquifers,” explains Blair.

Since its creation in 2004, the CWQRC has provided vital evidence-based advice to government and industry stakeholders on water quality and treatment in WA and Australia.

From 2005–2008, the centre collaborated on a WA-first research project through a $1.54 million grant funded by the Premiers Collaborative Research Program to determine the feasibility of micro-filtration and reverse osmosis processes to treat wastewater to acceptable health and environmental standards, for the purpose of replenishing drinking water aquifers. From 2006–2009, the centre also took part in a collaborative WA Government Water Foundation Project to determine requirements for managing aquifer recharge in WA urban areas.

This research laid the foundation for a $1.105 million Australian Research Council linkage project from 2009–2012, which was awarded to the CWQRC and its key partners – Water Corporation, GHD and Water Research Australia – to study novel chemicals, process optimisation of the wastewater treatment plant, and novel water treatment methods.

A collaborative team including current CWQRC Deputy Director, Professor Cynthia Joll, focused on analysing groups of chemical micropollutants, such as N-nitrosamines, benzotriazoles, benzothiazoles and iodinated disinfection by-products, as well as residual dissolved organic carbon, that were being uncertainly affected by the advanced water recycling treatment process.

“Our role has been to investigate chemical micropollutants of concern and their fate through treatment, and determine what advanced oxidation processes we could use to remove the few chemicals that had the capacity to pass through the reverse osmosis membrane,” says Joll.

This research was integral to developing the Groundwater Replenishment Trial, a $19.4 million federally-funded project that began recharge on 30 November 2010. During this time, wastewater recycling and groundwater replenishment were becoming central objectives of the Water Corporation’s 10-year plan for Perth (released in 2011) to help combat the city’s water shortage amidst a drying climate. The Groundwater Replenishment Trial was the precursor to the full-scale scheme.

“The information generated by the research helped in the development of a comprehensive health risk assessment for groundwater replenishment, which resulted in WA Department of Health support. It also informed the development of requirements for the trial and later the scheme,” says Blair.

The trial concluded on 31 December 2012. More than 7,300 community members toured the recycling facility and public support for a full-scale scheme remained steady at 76 per cent, an encouraging sign that concerns about chemical contamination in the recycled water had been addressed. Events such as community open days provided opportunities for community members to provide their feedback.

The progress of the trial was reported on the Water Corporation website, with monthly water quality reporting and a final report at the trial’s conclusion. It was also communicated to the public through media statements from Water Corporation and relevant WA Government ministers.

The trial won the 2013 Project Management Achievement Award for Sustainability and the Australian Water Association WA branch 2013 Infrastructure Innovation Award.

Joll explains why sustainability is critical: “Until now, customers have been using drinking water sourced from aquifers and producing wastewater, the majority of which is then treated and pumped into the ocean. However, by treating the wastewater to drinking water standards and pumping it into the ground, we are creating a sustainable, climate-independent water source.”

“… by treating the wastewater to drinking water standards and pumping it into the ground, we are creating a sustainable, climate-independent water source.”

On 1 August 2013, former Minister for Regional Development; Lands; Minister Assisting the Minister for State Development, Terry Redman, labelled the trial a “resounding success”, confirming that all of the 62,300 water quality samples taken during the trial met the required 254 health and safety guidelines.

With endorsement from the WA Departments of Health, and Water and Environment Regulation, Minister Redman then officially announced the Groundwater Replenishment Scheme.

From 2011–2016, the CWQRC published two book chapters, 14 refereed journal articles and six reports to industry on the subject and communicated its outcomes in 24 conference and workshop presentations. The research also contributed to the CWQRC and key partners being awarded a $1.1 million ARC linkage project from 2013–2016 to provide recommendations for treating wastewater in rural WA.

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