Extracting valuable resources in wastewater
In the EXTRACT project, we are exploring the potential for extracting biopolymers from wastewater sludge. Biopolymers can be used as a component in asphalt or cement.
Polymers—commonly used as binding agents in paint and plastic—are typically produced from fossil-based materials such as crude oil, which have a significant environmental impact. It is therefore an important milestone that, together with seven partners, we received a MUDP grant in 2025 for the development project EXTRACT.
By extracting biopolymers from sewage sludge, the project aims to utilize valuable resources in a circular way while reducing the volume of sludge by 15–25 percent.
Pilot plant at Marselisborg Wastewater Treatment Plant
The project has a total budget of DKK 10.35 million, which includes the establishment of a pilot plant at Marselisborg Wastewater Treatment Plant. Here, the product’s homogeneity and quality will be tested over an extended period.
Together with our partners, we are exploring the potential to extract biopolymers from sewage sludge using a membrane-based extraction process. If successful, and if the biopolymers meet the required quality standards, it is our ambition that they can be used in the future as a resource in asphalt, concrete, water treatment technologies, and as a flocculant at wastewater treatment plants.
Targeting a homogeneous product
The project is groundbreaking in Denmark and internationally. However, similar work on biopolymer extraction is taking place in the Netherlands. Project Manager Camilla Jessen from Aarhus Vand explains the difference:
In the Danish project, we are working with the extraction of active, conventional sludge, while in the Netherlands, extraction is carried out on granular sludge. In addition, we are integrating a membrane process that further ‘refines’ the product to achieve a more homogeneous and stable quality
Assessing the risk of spreading environmentally harmful substances
The first phase of the project focuses on determining whether environmentally harmful substances—such as PFAS—are transferred to the polymers during the extraction process. Thomas William Sevour, Associate Professor at the Department of Biological and Chemical Engineering – Water Technology at Aarhus University, and one of the eight EXTRACT partners, says:
“Protecting the environment and human health is our highest priority. We must be absolutely certain that levels of micro‑pollutants in the recovered biopolymers remain below regulatory thresholds, and this will be the focus of the initial phase of the EXTRACT project.”
FACTS
- EXTRACT stands for extraction of biopolymers from sewage sludge for circular reuse
- Project period: 1 February 2026 – 31 December 2028Total budget: DKK 10.35 million, including DKK 5.17 million in MUDP funding
- Project partners: Aarhus Vand, Vandcenter Syd, Aalborg Forsyning, Aarhus University, Alfa Laval, CRH Products, Munck Gruppen, and Envidan
- Project lead: Aarhus Vand