In the heart of Australia’s urban landscape, where the pressing demands of a growing population clash with the realities of climate change, pioneering water technologies are only treating wastewater but reclaiming valuable resources from it.
Working out of the QUT Water Innovation and Sustainable Environments Laboratory, and from the QUT School of Civil and Environmental Engineering, Professor Yang Liu is the chair of Sustainable Water Technologies and director of the $11.8 million Australian Research Council’s Hub in the Internet of Things for Water.
Her research aims to select natural microorganisms to perform treatments and detoxify contaminated environments, and to recover resources from waste materials.
“As we face significant climate and demographic changes, our urban water systems will need to adapt to more intense droughts, floods and fires,” Professor Liu said.
These stresses, she says, are compounded by an increasing population and competition for water resources, making effective management crucial.
“Current treatment systems are energy-intensive and overlook opportunities for energy and nutrient recovery, leading to high costs and significant environmental impacts in water and wastewater management,” she said.
The scale of the problem is sobering. According to reports from the United Nations, there are still around 2 billion people worldwide without access to safely managed drinking water. Over half of the global population lack safely managed sanitation services.
As something those in the western world can take for granted, water is at the core of sustainable development and its sustainable management is critical for socio-economic development, energy and food production, and healthy ecosystems.
With urban areas expanding and climate extremes becoming the norm, the need for innovative, sustainable water management technologies is at a boiling point.
From nature, for nature
Professor Liu's passion for sustainability started young. Influenced heavily by her father, she developed a keen awareness of the complex challenges facing the planet.
“Growing up in central Beijing, I didn’t have much direct contact with nature, but my dad had a huge impact on my interests,’’ she said.
“He was the president of the China Environment Publishing Group, and our home was filled with books about environmental issues, water and society. I remember spending hours reading through these books, fascinated by the problems and possible solutions they talked about. They sparked my curiosity and inspired me to pursue a career in environmental sustainability and research.
“Through university I learnt how water is such a critical resource, and how crucial water is for sustaining life and supporting industrial processes. I wanted to tackle the challenge of making wastewater treatment more efficient and sustainable.”
Professor Liu would go on to study a PhD in Environmental Engineering and Biological Sciences at the University of Wisconsin, Milwaukee, before moving to the University of Alberta, Canada. Here, she developed several new technologies tailored for treating municipal, agricultural and industrial waste and wastewaters which were successfully demonstrated at full-scale.
Now, utilising the power of nature, her work looks to harness microorganisms to create innovative, resource-recovery-based water and wastewater treatment solutions, offering substantial environmental and economic benefits.
“The science behind these microbes – understanding their functions and exploring their untapped potential – is incredibly fascinating,” she said.
“It’s not just about solving immediate problems by integrating engineering with microbial ecology, but also about uncovering new microbial functions and ecological responses. This approach not only advances sustainable development but also contributes to a more resilient future. The chance to make a real difference in the world while exploring the amazing science of microbes is what really motivates me.”
Current water treatment systems are energy-intensive and overlook opportunities for energy and nutrient recovery, leading to high costs and significant environmental impacts. By harnessing natural microorganisms and optimising engineered systems, Professor Liu’s research has led to innovations that have enhanced the efficiency of existing wastewater systems around the world.
“We’re focused on creating energy-positive solutions that allow us to recover nutrients, energy and even sequestering carbon into beneficial compounds,” she said.
“Microorganisms play a huge role in turning wastewater into valuable resources, and they do this with minimal energy use. By carefully managing the right mix of these microbes through engineering approaches, we can make the treatment process more efficient and even recover resources.”
Waste not, want not
Picture: Getty Images
From a circular economy perspective, the potential for recovery is vast, and as Professor Liu says, “there is no ‘waste’, only valuable resources to recover”.
Energy recovery from wastewater can be captured in the form of biogas, primarily methane, or biofuels like bioethanol that are generated during the anaerobic digestion of organic matter.
Nutrient recovery involves processes such as biologically enhanced phosphorus and ammonia recovery, eliminating the need for chemical additives and providing fertilizer and feedstocks for agriculture, and to purify liquid streams for safe water reuse.
“Nutrients can be returned as fertilisers, organic carbon energy can be harnessed for power generation, or used as a feedstock to replace fossil fuels," Professor Liu said.
"Water can be reused. It’s all about using nature’s processes to address big global issues and help our communities.''
The ‘ick’ factor
Despite the technological advancements, Professor Liu recognises that societal attitudes towards wastewater and recycled water remain sceptical.
“They often reflect outdated misconceptions,” she said.
“Education and transparent communication about the benefits and improved safety of recycled water, over urbanised river sources, coupled with successful case studies can help shift perceptions and build trust in these essential technologies.”
Promoting the safety and advantages of recycled water over conventional sources is crucial – from reducing the environmental impact and stress on fresh water supply to saving energy associated with transport and pumping. Professor Liu believes that we need a broader societal shift to change the way we view waste.
Collaboration is key
Indeed, the significance of Professor Liu’s research transcends the immediate benefits of efficient wastewater management.
“Addressing waste is crucial because it directly impacts climate change, pollution and biodiversity,” she said.
“With our increasing urbanisation, improper waste management not only leads to greenhouse gas emissions, but major water contamination and habitat destruction. What excites me most about my research is its transformative potential for addressing critical global challenges.
“This approach not only advances sustainable development but also contributes to a more resilient future. The chance to make a real difference in the world while exploring the amazing science of microbes is what really motivates me.”
But tackling such vast environmental challenges isn’t something Professor Liu can do alone.
“It takes a collective effort from researchers, industry partners and the community,” she said.
“I’m incredibly proud of the students I’ve trained. Seeing them go on to make impactful contributions to the field is one of my greatest achievements. Elsewhere, building strong partnerships and fostering innovation are key to achieving our sustainability goals. This collaborative approach not only enhances our research but also helps ensure that our solutions are effective and widely adopted.”
Aligned with the United Nations Sustainable Development Goals
In 2015, UN member states agreed to 17 global Sustainable Development Goals (SDGs) to end poverty, protect the planet and ensure prosperity for all.
