The relation between management practices of dredged material and the degradation of sediment organic matter

Thesis for the degradation of Soil Organic Matter (SOM) in dredged sediment vary based on the selection of management practices during the construction of Buiteneiland?

Climate change represents a significant global challenge, prompting action both internationally and locally (Calvin et al., 2023). Recognizing this issue, the Municipality of Amsterdam has established ambitious targets aimed at reducing CO2 emissions by 55% and decreasing primary resource usage by 50% by the year 2030 (Gemeente Amsterdam, 2020). These targets are taken into account by the Municipality of Amsterdam in the design of the land reclamation of the final island of the IJburg complex: Buiteneiland (Gemeente Amsterdam, 2020). This island contributes to the circular objectives of the municipality, particularly through the utilization of secondary resource streams from various parts of the city. The development of the land reclamation at Buiteneiland requires the transportation and handling of dredged sediment, which is a byproduct of the construction process. Currently, there is a lack of established practices for managing this sediment.

With the construction of Buiteneiland, the Municipality of Amsterdam faces the challenge of effectively managing approximately 80,000 m³ of dredged sediment expected to be generated during the process (personal communication Smits, 2024). Dredging, the physical removal and relocation of sediment from aquatic systems, is a crucial practice in the Netherlands (Wenger et al., 2017). Through dredging, the balance between water and land is managed to serve human needs. While dredging is essential for maintaining drainage capacity, enhancing navigability, and improving water quality, it also poses socioeconomic and environmental challenges (Laboyrie et al., 2018).

This study focuses on understanding the management practices associated with dredged sediment in the context of the construction of Buiteneiland. It aims to explore the various approaches to sediment management in the Netherlands. Moreover, in order to understand the mechanisms by which we can mitigate greenhouse gas (GHG) emissions and effectively utilize secondary sediment, thus fulfilling the circularity targets, it is essential to understand the carbon-related biogeochemical processes. The degradation of sediment organic matter, influencing the carbon cycle dynamics, is directly and indirectly related to the biogeochemical processes (Arndt et al., 2013). The mineralization, complete microbial degradation, of sediment organic matter leads to the formation of inorganic substances such as CO₂, CH₄, and N₂O. This study will investigate the microbial degradation of sediment organic matter (SOM) in dredged sediment, simulating anaerobic and aerobic management practices.

While previous research has addressed GHG emissions from dredged sediment, there remains a knowledge gap concerning the specific impacts of different management practices on GHG emissions. Therefore, this study aims to enhance understanding of the relationship between sediment organic matter degradation in dredged sediments under various management practices. By focusing on a case study within the Municipality of Amsterdam, concerning the construction of Buiteneiland, this research provides insights into the environmental implications of dredged sediment management and its contribution to GHG emissions.