Environmental System Analysis on Sediment Management : A Case Study on Port of Hamburg

Dredging of sediment is sometimes required in order to maintain depth of harbors or excavate contaminated sediment. However, dredging and handling of dredged sediment have impacts upon the environment. The European project Sustainable Management of Contaminated Sediment (SMOCS) was established in late 2009 to develop more sustainable sediment management (i.e. dredging and handling of dredged masses) as well as guidelines and tools to assess sustainability in decision making.Sediment management generally requires permission, which needs to be founded on sound and reliable information of the handling options. This is normally done through an Environmental Impact Assessment (EIA), which evaluates the environmental advantages and disadvantages of planned activity. Although, in order to compare the handling alternatives relative to each other Environmental System Analysis (ESA) is a better method.In order to find the most sustainable handling alternative, the aim of this study is to compare four different scenarios for management of contaminated sediments in the port of Hamburg, Germany. The comparison is made by an ESA, based on the methodology of Life Cycle Assessment (LCA). The comprehensive aim is to improve and ease the procedure of permitting sediment disposal. Furthermore, the results of the study will be used for comparison with earlier ESA studies in order to generalise results.The results show that beneficial use of dredged sediment in road construction, brick production or as construction material upon landfill is the best handling alternative. The second best alternative is disposal in river, followed by on-land disposal. Disposal at sea is the worst scenario due to long transportation distance. Furthermore, transportation is an important factor to decrease in order to minimize environmental effects, especially in sea disposal. Production of conventional construction materials is another energy consuming factor that has to decrease. Uncertainties are linked to old emission factors regarding vehicles. Lack of case specific data on for instance German electricity production and density of construction material etc. also contribute to less certain results.Conclusions are that beneficial use of dredged masses is preferred and most profitable in Hamburg, but on-land disposal of dredged masses might not be the worst handling alternative in all ports. This may depend on type and amount of construction material and distance to landfill. German legislation enables further beneficial use of dredged masses, which leads to more handling alternatives in Hamburg compared to Sweden. It is hard to compare ESA:s on Port of Gävle and Oxelösund to Hamburg due to different handling alternatives, treatment and sediment properties etc. However, ESA seems to be a better and more specific tool to evaluate environmental impacts than EIA and thereby ease decision making.Validerat; 20110407 (anonymous)