As we approach the end of our #FERROResults social media campaign, FERRO is dedicating the final result to sediment removal and nutrient recycling. The project has made significant progress towards its objectives, delivering innovative solutions, and now it is presenting its final step towards bettering lake restoration and management.

Background: Why is sediment removal and nutrient recycling needed in lakes?

Sediment removal is among the most effective strategies for improving ecological conditions of lakes in the long-term, as it eliminates the source of internal phosphorus loading. Additionally, the extracted sediment can be repurposed as a phosphorus fertiliser, providing benefits that extend beyond improving lake ecological conditions. However, this method is accompanied by several environmental concerns and is often costly, making it more practical for relatively small lakes. Furthermore, the agricultural reuse of sediment phosphorus may face challenges due to high levels of contaminants and the limited bioavailability of sediment phosphorus for crops. Consequently, further refinement and development of this approach are essential to maximize its potential benefits while addressing its limitations.

How will this be achieved: FERRO’s approach

FERRO proposes targeted sediment removal, i.e. focusing on hotspot areas, as a cost-effective solution that may also be applicable to larger lakes. Opportunities for targeted sediment removal are explored using experimental data collected from six lakes in southern Finland. These studies encompass sediment phosphorus dynamics, sonar surveys of lake sediments, and greenhouse gas dynamics. It is hypothesized that hotspots of sediment phosphorus release may also serve as potential hotspots for greenhouse gas emissions, highlighting the broader environmental impact of lake restoration efforts.

Additionally, FERRO aims to demonstrate a cost-effective lake restoration approach through sediment removal at Lake Mustijärv, which serves as the experimental site for the project.

Finally, best practices for sediment phosphorus recycling are developed through a six-month greenhouse experiment using sediment collected from the six study lakes in southern Finland, as well as sediment removed from Lake Mustijärv. It is hypothesized that lime, biochar, and microbial treatments can enhance sediment P recycling while reducing negative environmental effects.

Who will benefit from this?

Lake restoration practitioners will gain valuable insights from a practical, evidence-based approach that demonstrates the cost-effective potential of sediment removal, facilitating its broader replication. Targeted sediment removal offers water quality managers a novel, practical and efficient tool to improve ecological conditions while delivering also multiple socio-economic co-benefits. The agricultural sector will benefit from access to a sustainable phosphorus fertilizer, along with guidance on its application. This reduces reliance on conventional mineral phosphorus fertilizers, which are derived from nonrenewable phosphate rock—a resource that is unevenly distributed globally. The general public will benefit from improved water quality and reduced nutrient pollution, achieved through the integration of circular economy principles. Additionally, this approach fosters significant socio-economic co-benefits, such as reduced greenhouse gas emissions, enhanced biodiversity, and healthier ecosystems. Finally, the initiative contributes to scientific advancement by addressing critical knowledge gaps, driving innovation, and supporting the regeneration of essential environmental science.