The world’s wastewater treatment plants produce millions and millions of tonnes of sludge that is not exploited optimally.
This sludge is typically used in biogas plants, incinerated or spread on fields as fertiliser. This is not optimal, because the sludge contains many very valuable substances that have many uses, such as in bioplastics and building materials – and in the future perhaps also in food and medicine.
Bacteria in sludge produce valuable biopolymers, and they need to be used much more in the future.
This is the aim of an ambitious research project for which Per Halkjær Nielsen, Professor at the Department of Chemistry and Life Sciences at Aalborg University, has received a DKK 55 million Challenge Programme grant from the Novo Nordisk Foundation under its Recycling for a Sustainable Society theme.
“About one third of the sludge from wastewater treatment plants globally contains biopolymers, which are incinerated as low-energy products or spread on fields instead of being extracted and used more sensibly ,” explains Per Halkjær Nielsen.
Biopolymers can already be recovered
All living organisms produce biopolymers. One example is gelatine, which is obtained from pigs. Another example is cellulose, produced by trees.
Bacteria are added to wastewater to purify it, but they also produce substantial biopolymers that comprise biosludge, which accounts for more than 10% of the total biowaste produced in high-income countries.
One partner involved in this major research project is the recipient of the 2022 Novozymes Prize, Mark van Loosdrecht from Delft University of Technology in the Netherlands. He is an international leader in extracting biopolymers from some types of biosludge – a promising but rather unexplored field.
Major contribution to the circular economy
The research will involve scientists from Denmark and the Netherlands, who will investigate the composition of bacteria in wastewater treatment plants throughout the world. Aalborg University and Per Halkjær Nielsen have studied the complex composition of the microbiome in wastewater systems for several years and therefore uniquely understand the relationship between how wastewater treatment plants function and the microorganisms present.
The purpose of the study is to determine the potential various wastewater treatment plants and countries have for producing specific commercially attractive biopolymers.
This requires determining the optimal composition of bacteria in wastewater for producing biopolymers and which products can be made from the extracted biopolymers.
“As we begin to move away from using oil-based polymers, biopolymers will be in short supply, and using biosludge is therefore a really good idea. This could be a crucial contribution to the circular economy. However, determining what we can expect to extract from the various treatment plants is important,” says Per Halkjær Nielsen.
Application-oriented fundamental research
In addition to determining the potential of the world’s wastewater treatment plants, researchers must also develop methods for extracting biopolymers from biosludge more efficiently.
The researchers will conduct a series of experiments aimed at characterising the biopolymers and their properties to determine where they can potentially be used.
Per Halkjær Nielsen says that the grant from the Foundation will enable researchers to explore the subject thoroughly and carry out solid application-oriented fundamental research.
“The grant will also provide some opportunities to collaborate with other leading researchers in this field. This may be an important contribution to developing the circular economy and wastewater management, and I am delighted to be leading the project,” he adds.
The Novo Nordisk Foundation established the Challenge Programme in 2014. Since then, the Foundation has awarded more than DKK 100 million every year for ambitious research focusing on global challenges.
The Challenge Programme targets research projects based on a thematic approach addressing some of the major societal challenges.
In 2022, six researchers have received grants totalling DKK 337 million through the Challenge Programme. Read about all the grants here.
Christian Mostrup, Head of Press, Novo Nordisk Foundation, +45 30674805, email@example.com