Driving energy recovery from wastewater

Recent developments in energy recovery from wastewater provide enormous possibilities for the water and wastewater industries. It’s researchers like Dr Xuan Li at the University of Technology Sydney pushing the envelope.

Recent developments in energy recovery from wastewater provide enormous possibilities for the water and wastewater industries. It’s researchers like Dr Xuan Li at the University of Technology Sydney pushing the envelope.

Dr Xuan Li is a Chancellor’s Research Fellowship recipient at the Centre for Technology in Water and Wastewater (CTWW) at the University of Technology Sydney (UTS). She obtained her PhD from the University of Queensland (UQ) in Environmental Engineering in 2020. She has published nine book chapters and serves as a paper-handling editor and a lead special-issue editor for several highly regarded scientific journals.

Originally from Taiyuan in Shanxi Province, China, Li developed her interest in environmental engineering based on her experience at home.

“The city where I grew up was heavily engaged in mining activities,” said Li. “I have seen a lot of environmental pollution issues, including air and water pollution. Air pollution was a massive problem in my town because a lot of kids (including myself) suffered from respiratory diseases. When I graduated from high school in 2011, I was thinking about what I could do to help improve the situation in my hometown. This became my motivation to choose a major for my undergraduate degree at Tianjin University.”

What is she studying?

Li’s research focuses on energy recovery, microalgae, biofuel, wastewater treatment, sewer concrete corrosion, and wastewater-based epidemiology. She has four goals as part of her research. First, she wants to increase the energy recovery from wastewater. Second, Li is studying microalgae-based, carbon-neutral wastewater treatment. Thirdly, she is developing an early disease warning system, and finally mitigating the corrosion in the sewage system.

“Wastewater treatment seemed more like a natural progression in my academic journey,” Li said. “During my undergraduate studies, I had the opportunity to participate in a research project that involved using wastewater to produce biodiesel. The project also sought to recycle wastewater that can then be used for flushing purposes. This experience kindled my interest in wastewater treatment, and I subsequently pursued further research in this area during my doctoral studies.”

Wastewater epidemiology is one particular area of interest for Li. The public health news of the past three years was a strong influence after she graduated with a Ph.D. from UQ.

“I was aware of the field while doing my Ph.D., but never really looked into it,” she said. “As the COVID pandemic raged around us all, it occurred to me that wastewater-based epidemiology could be extremely helpful in estimating the infection status of a community. It could provide an early warning for the healthcare system.”

This inspired Li to start studying the field as a postdoctoral research fellow at UTS. Her first step was to assess the feasibility of wastewater-based epidemiology for estimating community infection rates.

“I also investigated the sources of SARS-CoV-2 shedding into wastewater and the associated infectivity,” Li said. “I also developed artificial intelligence models that sought to predict future cases and hospitalisation numbers. These are all important for the health system, as they can predict peaks and troughs in patient numbers.”

Her research in this field has been published in a range of prestigious scientific journals. It was also picked up by a range of broadcasting networks, including the National Broadcasting Corporation (NBC), Columbia Broadcasting Systems (CBS), and the American Broadcasting Corporation (ABC) in the United States.

Findings by Li

Li’s research has covered a series of topics. Her primary foci have been concrete corrosion in wastewater infrastructures, wastewater-based epidemiology for assessing infectious diseases, innovations in energy recovery, and removing emerging pollutants within wastewater treatment.

“Corrosion-resistant concrete is an important innovation for the wastewater industry,” she said. “A lot of the existing infrastructure for the wastewater industry is made out of concrete, and extending its service life is a cost-effective way to keep the infrastructure going. I was able to develop an innovative corrosion-resistant concrete. It’s not only environmentally friendly but is also cost-effective. The corrosion-resistant concrete can extend the service life of the concrete by up to 50 per cent.”

Her research into corrosion-resistant concrete was paired with a prediction tool for wastewater facilities to plan their maintenance times. The prediction tool looked at the different types of corrosion and the likelihood of it appearing in different parts of a wastewater facility.

Li’s studies also considered the increased number and ferocity of extreme weather events due to climate change. Both flooding and drought events are going to be damaging for wastewater infrastructure, so her research proposed an adaptation approach to wastewater facilities.

“When it comes to energy recovery and removing emerging pollutants from wastewater treatment, I developed an innovative approach,” she said. “It utilises waste by-products to enhance energy recovery and improve the removal of emerging pollutants. I have been focusing on PFAS, microplastics, and anti-biotic resistant genes.”

Her research team is now working on improving the removal of PFAS and microplastics through wastewater treatment. In Li’s mind, the best control method is to actually minimise its usage from the source.

“It’s hard to find products these days that don’t have either PFAS or microplastics in them,” she said. “That includes things that you would never think about. For example, a lot of face washes and toothpaste have microplastics in them. On the other side of the coin, PFAS can be found on non-stick frying pans or popular brands of workout clothes. The best thing people can do is to do research into the product. They need to make sure that the product does not contain PFAS or microplastics. They should also try and reuse plastic containers wherever possible. That even goes into properly disposing of them since they can shed microplastics into the natural environment.”

Award winner and collaborator

Li’s ground-breaking work in energy recovery saw her and her research group nominated for the Eureka Prize for Applied Environmental Research. It was the only wastewater treatment group that has ever been nominated for the prestigious award. This research project was done in conjunction with South East Water.

“The project was implementing the novel technology by using waste by-products,” said Li. “The industry knows that it is going to need additional chemicals for additional treatment processes. That will increase the costs and environmental footprint. By using this waste by-product, we can eliminate or reduce the environmental footprint of wastewater treatment. It can also reduce the pollutant discharge. The research also dealt with emerging pollutants and energy recovery at the same time.”

Li has collaborated with South East Water for several years. She has found it to be a positive experience.

“When I was first looking for a partner, I worked with Water Research Australia (WaterRA),” she said. “They acted as a matchmaker to connect researchers with potential collaborators. It was through them that we found South East Water. As a water utility, they have a variety of challenges that they want to help with. Our group worked with them on the first project, and that went well. As a result, we have received a range of different projects from them. It’s a win-win situation as we are helping them with their issues, and South East Water is providing an industrial perspective into our research.”

It is not the only award that Li has won. She won the 2023 WH Gladstones Population and Environment Award from the Australian Academy of Science. This represents an important milestone in her career.

“Receiving this award is not only a tremendous acknowledgment of my dedication and contributions,” said Li. “It also marks my inaugural recognition from the Australian Academy of Science. Beyond personal achievement, I view this award as a powerful platform to inspire young girls in future generations to embark on academic journeys in STEM fields. It underscores the importance of gender diversity in scientific and academic domains, encouraging and empowering the scientists of tomorrow, regardless of their gender, to pursue their passions in the world of science and innovation.

The future for Li

In the future, Li wants to establish herself as an independent researcher. By creating her own teams, she can look into some other fields.

“I would like to study areas that are more closely related to our daily lives, our health, and the urban infrastructures. All of this together supports my studies into pollution control, and that way, I will be helping the world.”

For more information, visit https://www.uts.edu.au/research/centre-technology-water-and-wastewater

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