My overview
Many Danish lakes are in poor ecological condition as a result of decades of nutrient accumulation in the lakebed. A new project will develop a new generation of gentle sediment cleaning for lake restoration and demonstrate the technology in three Danish lakes. By combining gentle pumping of phosphorus-containing lake sediment and the use of industrial hemp for the possible removal of harmful substances, such as heavy metals, valuable phosphorus will be recovered from the sediment and reused as fertilizer in agriculture. Innovation Fund Denmark is investing DKK 22.1 million in the RESTORE project.
Lakes are among the most heavily impacted ecosystems in Denmark and the rest of Europe. Although nutrient discharges into lakes have been reduced in many places, phosphorus-rich sediments continue to release nutrients into the water. The result is turbid water, algal blooms, loss of biodiversity, and greenhouse gas emissions. A new Grand Solutions project, RESTORE, will now demonstrate a sustainable and circular solution that both restores the lakes’ ecological condition, reduces greenhouse gas emissions from them, and recycles valuable resources for agriculture.
Gentle dredging will be tested in practice
RESTORE will develop an improved sediment remover (Søbot) that can remove the nutrient-rich surface sediment more gently and efficiently than existing solutions. The technology will minimise sediment resuspension during operations and be adaptable to different lake types and local conditions. This will allow dredging to be carried out with less impact on the lake ecosystem and with better opportunities to collect the sediment for subsequent treatment and recycling.
“We are facing a major societal challenge, with many lakes affected by decades of nutrient accumulation. With RESTORE, we are developing a solution that not only restores the lakes’ ecological balance, but also makes it possible to recycle phosphorus as a valuable resource. This could create a new paradigm for lake restoration in Denmark and internationally,” says the RESTORE project management.
As part of the project, sediment will be removed at full scale from three Danish lakes. The researchers will monitor the lakes before, during, and after dredging to document the effects on water quality, biodiversity, and greenhouse gas emissions. At the same time, they will investigate how the collected sediment can best be treated and reused as phosphorus fertiliser in agriculture, including by testing whether industrial hemp can reduce levels of environmental contaminants and heavy metals through phytoremediation.
Potential for a new company and international rollout
In the longer term, the ambition is to establish the basis for a new company that can offer sustainable lake restoration as an end-to-end solution. The potential is significant, as Denmark has more than 100,000 lakes and ponds, while similar challenges exist in millions of lakes across Europe.
The project brings together researchers and companies with expertise in environmental technology, lake ecology, sediment management, and commercialisation. Together, the partners will document the entire value chain—from dredging and improvements to the aquatic environment to resource recycling and the development of new business models.
Fakta
- Innovation Fund Denmark’s investment: DKK 22.1 million
- Total budget: DKK 29.9 million
- Duration: 4 years 9 months
- Official title: Sustainable lake restoration by sediment dredging and nutrient recycling
Partnere
- University of Southern Denmark (project lead)
- Aarhus University
- WOLFF
- Danish Engineer Service (DIS)
- DALGAS
- AMINORD