Environmental impacts of Golden Horn dredgings

Abstract

It is possible to pollute water resources with domestic, industrial and surface materials, and in some cases, water resources may begin to fill up. Depending on the water pollution, the sediment can be polluted and even if the water pollution is controlled, it continues to be a source of pollution. One of the most frequently applied methods to control sediment pollution is dredging. This method is also used to prevent water bodies from being filled with materials such as sediment brought in by the water sources that feed them. The management of dredged materials depends on their contamination status. Dredged materials with high pollutant content can be treated by physical, chemical and biological methods or disposed of in specially established facilities for the removal of these materials. During the implementation of the dredging project, it is possible for pollutants leaking from the sediment pore water or present in the fine-grained particles of the sediment to diffuse into the water body, and emissions to water and air depending on the equipment used in the dredging works. It is possible that the environmental impacts of a dredging project that is not implemented carefully will result in adverse impacts. In this study, an evaluation was made on the environmental effects of the dredging works applied both for pollution control and to prevent the Golden Horn from being completely filled. The study includes dredging studies conducted between 2016-2020. The management status of the dredged materials, which were applied at the beginning of the dredging works in the Golden Horn, in the sludge dams established in the quarries, and the dewatering of the dredged materials, which started to be applied later, and their disposal in the sanitary landfill facilities were examined. In addition, the effects of producing bricks with dredged material as an alternative method were investigated. In order to evaluate the environmental impacts of the dredging works, 1 m3 of dredged material was chosen as the functional unit. The system boundaries have been chosen to cover the extraction and transportation of the raw materials to be applied in each process, starting with the removal of the dredged material, its transportation, dewatering, removal and beneficial use. As a result of the life cycle assessment applied, it has been shown that the environmental impact of the disposal method in the sludge dams, which is the first method applied in the Golden Horn, is the most depending on the preparation of the removal area. As a result of the introduction of the landfill method, it has been concluded that although the applied methods require electricity consumption, it is more advantageous than the disposal case in sludge dams. Furthermore, the impacts of brick production with dredged material were compared with traditional clay brick production, and it was concluded that brick production with sediment was an advantageous method.