Fourteen years ago, Minh Duc Nguyen was completing his bachelor’s degree at Hanoi Architectural University. Now, he is a well-regarded water and wastewater engineering researcher, a consultant at Isle Utilities and the 2023 AWA Student Water Prize winner.
“When I started my career, I was very focused on water, specifically the drinking water side. It wasn’t until later that I realised that wastewater is not just waste, but a resource.”
These are the words of Minh Duc Nguyen. He has recently completed his PhD in the beneficial reuse of sludge from drinking water treatment process at Deakin University in collaboration with Barwon Water. Nguyen’s research examines how a cost centre for water utilities can be a source of revenue.
“I’m more interested in the recycling, circular economy and resource recovery side of things,” said Nguyen. “When it comes to the lifecycle of the economy, I want to work out how we can reuse waste. Ideally, the industry would be retrieving all the nutrients and resources normally considered waste and finding a way to reuse them, so it’s a circle.”
Wastewater has reached a new nadir where nothing is wasteful; it’s all a resource. Along with others within Australia and worldwide, his goal is to work out how to return those resources to life.
“We need to work to reduce our environmental footprint and bring about a more sustainable way of living,” he said.
From Hanoi to Geelong
When reflecting on his career path, Nguyen believes that he has one of the more unusual career paths.
“I’ve walked the line between academia and private industry,” he said. “I tended to swap between the two for a few years but questioned what I could do next. About three and a half years ago, I was reviewing the Water Research Australia (WaterRA) website and found a lot of exciting projects. The one that captured my attention the most focused on reusing and recycling waste from drinking water processes. That’s what brought me to Australia to complete my Ph.D.”
Despite his less-than-traditional career path, Nguyen believes his movement between academia and industry has given him unique skills.
“Because I’ve walked the line between academia and industry, I understand both languages. It’s also helped me understand what each area is doing and how to collaborate with both groups,” he said.
Moving on from the Australian and New Zealand Biosolids Partnership (ANZBP)
For the past two and a half years, Nguyen has been a program manager for the Australian and New Zealand Biosolids Partnership (ANZBP). ANZBP is an Australian Water Association’s industry program of utilities, consultants, academics, and government bodies committed to the sustainable management of biosolids. It provides interested parties with factual information about biosolids, how they are produced, what is in them, how they might be used, as well as their benefits and potential risks associated with their use. The ANZBP believes biosolids are a valuable product and provides information supporting biosolids’ application to land and other appropriate uses.
“Being a part of ANZBP allowed me to understand and learn far more about biosolids,” said Nguyen. “It was previously an unknown field of study, but I have since realised that it is a beautiful resource that we can bring into a wide range of beneficial applications.”
The ANZBP is playing a role in promoting research and collaborations with the water and wastewater industries. It is also driving the industry towards a more sustainable approach to biosolids. However, the management of biosolids has its challenges.
PFAS causing problems in biosolids
PFAS are a group of chemicals used to make fluoropolymer coatings and products that resist heat, oil, stains, grease, and water. Officially known as pre- and polyfluoroalkyl substances, work is underway worldwide to remove and eliminate these chemicals from almost everything.
“With any regulatory change from the government, the biosolids space is hunting for a long-chain polymer that can replace PFAS,” Nguyen said. “Currently, PFAS starts at the industrial level and winds up everywhere, including wastewater and biosolids. While people seem fine with PFAS in their dental floss, mascara, clothes or cookware, they tend to freak out about PFAS in their waste.”
Nguyen has a passion for helping people understand the beneficial use of biosolids. There are many opportunities to treat waste products as a valuable resource and keep them out of landfill. He is convinced that continuing to throw biosolids out is working against the goals of resilience, sustainability, and combatting climate change.
“The thermal treatment of biosolids and waste, also known as pyrolysis, provides new developments for the circular economy. One area of particular interest is alum sludge,” he said.
Alum sludge
The focus for Nguyen in his PhD was on alum sludge. It tends to be a quiet area of research, with a small amount being done in this field. Also known as alum sludge, it is the by-product of purifying drinking water. A salt containing aluminium is used as a coagulant, capturing impurities and contaminants in drinking water. However, the remaining sludge has long been treated as waste, winding up in landfill.
“As part of doing my PhD at Deakin University, I found that the alum sludge could be a vital resource when considering the circular economy. As technology improves yearly, it shows we can develop better ways to recover resources,” said Nguyen.
The majority of alum sludge is stockpiled and eventually dumped in landfill. Alum sludge has enormous potential to absorb PFAS or prevent algal blooms.
“The contaminant absorption capacity of alum sludge appears significant,” Nguyen said. “Alum sludge tends to be comparable to biochar developed from biosolids in terms of PFAS adsorption. The big advantage is the significantly reduced energy requirements. This comes from the thermal requirements to generate biochar.”
“If we can turn that waste into a useful resource that can be used in multiple areas, then we are closing the loop,” he said. “That’s a great example of how we can create a circular economy, and it should be a new focus for the future.”
Winning the Student Water Prize
The Australian Water Association’s OzWater in Sydney also received several awards. One of the award winners was Nguyen, who won the Student Water Prize for his research. He views this as a tremendous honour.
“It has meant a lot to me,” he said. “I’m just a Vietnamese-Australian doing a tiny amount of work to try and improve waste management in Australia. Being recognised for all the hard work and ups and downs was an absolute pleasure. I arrived in Melbourne just a few months before the pandemic. I could not visit my family during that time, so it was a massive struggle. However, the award is an amazing payoff for all the time, hard work, sweat and tears I have spent on my PhD.”
Biosolids in wastewater have received a lot of attention, but this is different from Nguyen’s focus on alum sludge. He believes that by receiving this award, he is raising awareness for alum sludge, along with its recycling and reuse. Australia has enormous potential to become a globally recognised hub for alum sludge recovery and reuse, off the back of Nguyen’s research.
Future of biosolids and wastewater
Nguyen believes that the vast majority of players within the wastewater and biosolids industry are moving towards the circular economy. He hopes that more will continue to help turn biosolids and wastewater into something valuable and reusable.
“I think that the increased focus on sustainability, resource recovery, and the circular economy will increase efficiency, cost-effectiveness, and become more environmentally friendly,” he said. “With the increased uptake of artificial intelligence and smart technologies, I hope we can transform the wastewater and biosolids industry to create a better environmental aspect.”
When it comes to his role, Nguyen wants to be a continuing influence in Australia. However, he is looking beyond that.
“I hope we can expand our expertise and technology for developing countries. It would be great to be supporting countries like Vietnam, Cambodia, and the Pacific Islands. Australia can be a leader in tackling issues in the water and wastewater industries.”