The shrinking barriers to widespread wastewater reuse

Reusing municipal wastewater for residential non-drinking end-uses offers plenty of opportunities to bolster water security and help conserve the environment. Recycled wastewater schemes, however, often come with a price tag — and a barrier to wider adoption.

AWA Water Quality Specialist Network co-chair and Aurecon Water Lead Engineer Sally Williamson said that while sustainability and environmental concerns are continuing to increase interest in domestic wastewater recycling schemes, there are still significant barriers to further implementation.

“We have some pretty obvious sustainability and water security concerns around Australia. Recycling wastewater from homes and applying that water locally is an option for reducing potable water use,” she said.

“Furthermore, in our inland areas where the window of opportunity to discharge the leftover wastewater into waterways is closing, we are being driven towards finding alternatives.

“So there is also the environmental protection driver — and one option is to divert that leftover wastewater away from the environment by reusing in the community.”

Williamson said utilities and developers are certainly considering recycled water as an option, particularly in regards to new developments, but that funding these initiatives can be expensive.

“There is quite a lot of planning happening around Sydney’s new airport, and a new advanced water recycling centre will be constructed there as well as at Sydney Science Park, both of which will likely be supplying recycled domestic wastewater to the new developments in the region,” she said.

“However, for something that seems relatively easy to do, we’ve not yet seen a lot of third-pipe reuse schemes get off the ground. There have historically been barriers, with the main one relating to implementation cost.”

Pricing out recycled water

While the cost of different water sources varies around Australia, recycled water is, for the most part, still more expensive to supply than potable water. Capital investment is required, including treatment and networks, there are ongoing operational costs, and pitching higher bills to customers is hard to do.

“Who is going to pay for reuse options? As a customer, why would I pay more for recycling when potable is cheaper? Recycled water costs more to produce, and when the service seems the same as what already comes out of the tap, the customer’s willingness to pay is a barrier,” Williamson said.

Williamson said another key consideration around cost is also about ensuring recycled water is fit for purpose, which is about making the level of treatment appropriate for the end-use. 

“I was involved in the WateReuse Research Foundation project 10 years ago looking at this concept and how we were potentially overtreating the water for a range of end-uses. We also compared the ways of treating fit-for purpose recycled water with a triple-bottom line assessment,” Williamson said.

“One of the big things that has changed in the last decade since that investigation is technology — it’s changing fast.

“We are making advances in technologies around treatment, and analysis and online monitoring, that may allow us to recycle more cost effectively. And that will see the cost of producing recycled water go down.

“There is a lot happening in this space, and the more improvements we see in technology, the closer we’ll get to override that cost barrier, where recycled water can be produced and supplied at a similar cost to potable water.”

Risky regulation

While cost has historically posed the biggest barrier for wider uptake of recycled water schemes, Williamson said risk considerations and regulation have historically made uptake more difficult, too.

“Greywater reuse is not new. Water conscious consumers have been reusing washing water for their gardens for a long time. But compared to municipal operated recycled water schemes, there is the risk factor to consider as the onus of risk management shifts from the consumer to the scheme operator as the producer of the recycled water,” Williamson said.

“There are many hoops to jump through to ensure that recycled water of any type is going to be used safely and for its intended purpose. 

“There are many checks and balances involved, particularly around instrumentation and operational corrective actions, and preventative barriers, to make sure the health of customers is protected.”

While the Australian Guidelines for Water Recycling provide an overarching framework for regulation, Williamson said some states and territories have different regulations for domestic wastewater recycling and reuse.

“These regulations differ in each state and territory. However, there is a process that must be followed around the quality management framework, which is typically common to regulations regardless of where you are in Australia. The general gist is that to operate a recycled water scheme, you have to make sure it’s achieving the water quality required to be safe by proactively managing risks,” she said.

“I’ve worked in different states, and there are often differences in the requirements set out by respective regulators.

“Going from state to state, there are additional potential barriers to getting these schemes off the ground due to these different approaches to regulation.”

While Williamson said New South Wales has been more progressive in assessing recycled water schemes, whereas in 2020 the Victorian government reviewed and updated its recycled water guidelines, with the aim of improving the approval processes for recycled water reuse.

Trending opportunities

Despite needing to mitigate the legacy of risk-averse thinking, Williamson said the increasing drive to build more sustainable and liveable cities and regions is playing a role in positive change.

“The drive to build more water-resilient, sustainable and liveable cities is becoming more prominent. We are seeing the need to reuse water being included in council development plans. It’s not just wastewater either, it’s also about stormwater, too,” she said.

“In inland communities, urban stormwater can also have quite a significant impact on waterway health. There is a big push now to maintain or improve our waterways for environmental and aesthetic reasons, so that we can have waterways for amenities.

“Also, we are even seeing a lot of customers reaching out to utilities because they are introducing sustainability policies that are driving them to reduce their potable usage. Customers are starting to be willing to pay more to meet their own targets.

“These trends are great to see. They indicate that there are still plenty of opportunities available for making recycled water schemes viable moving forward.”