Life cycle assessment of management scenarios for dredged sediments: environmental impacts caused during landfilling and soil conditioning

The management of dredged sediments is a challenging issue since it involves the interconnection of complex economic, social, technical and environmental aspects. The EU LIFE SURE project aimed to apply a more sustainable dredging technique to Malmfjärden Bay in Kalmar/Sweden (a shallow urban water body with a high content of nutrients) and, additionally, it involved beneficial uses for the dredged material, in line with the circular economy concept.

To achieve the authors carried out a life cycle assessment to assess the potential environmental impacts associated with two scenarios: sediment landfilling and soil conditioning. This LCA study also aimed to evaluate and compare the costs related to each scenario. Results showed that soil conditioning was the scenario with least environmental impacts and the best economic evaluation, owing to positive environmental savings produced by reducing fertilizer consumption (which also avoided purchase costs). However, it was also linked to potential negative effects associated with eutrophication and toxicity. In order to mitigate this problem, the sediments could be pre-treated to reduce their risk of pollution.

The main impact of the landfilling scenario was the emission of greenhouse gases during the operation of the facility. The authors recommend implementing the soil conditioning scenario, in line with the aims of the LIFE SURE project.