## 1 Introduction  
Sediments are dredged from water bodies to ensure proper water levels or restore aquatic ecosystems worldwide. This dredging activity produces large volumes of sediments that reach the land and need adequate disposal management. According to SedNet (the European Sediment Network), Europe annually produces more than 200 million m\({}^{3}\) of dredged materials [1]. Dredged sediments are commonly disposed of in open oceans or landfills. However, traditional methods are restricted by legal and environmental concerns. On the one hand, open ocean disposal is banned in several countries due to its potential contamination of the surrounding environment [2, 3]. On the other hand, landfilling is associated with a high demand for space and the production of risky by-products [4]. However, both methods face restrictions due to legal and environmental concerns. One example is the European Landfill Directive (1999/31/EC) [5], which has caused some landfills to close, resulting in a reduction in the space available for landfills and higher landfilling costs [6]. A recent assessment (2008-2014) of European dredged material by the OSPAR (2017) [7] estimated that 20-40% of dredged material [8] is highly polluted by human activity, mainly those related to fine grain size [7]. Incorrect management would adversely affect the ecosystem, so strict regulations enforce that the material must be treated before the sediments can safely be sent back into the environment or landfilled. Current treatments are not cost-efficient; they have high energy consumption and do not effectively separate water from contaminated solids that must be transported to landfills with a very high moisture content (>30%), which increases transport and disposal costs exponentially [9; 10]. More importantly, these technologies do not allow solids and water cost-efficient vaporization, which might bring important environmental and economic benefits (circular economy) [11]. As a result of the high treatment costs and the lack of treatment in some highly contaminated cases, many coastal and fluvial areas need to stop dredging, which may have a negative economic impact on the area (e.g., reducing the number and draught of ships the port can accommodate) [9; 12]. However, several environmental, economic, social and technological factors determine the viability of implementing the proposed practices. Social aspects require attention, particularly the end-user acceptance of using sediments. Investment and operational costs are also barriers because using sediments in industries could require new sources of income for the development of technologies, adjustments and upgrades of existing practices, as well as the implementation of cleaning-up technologies, among others [13]. The composition of the dredged material is a decisive factor in determining the viability of using sediments for beneficial purposes. Typically, sediments contain organic matter, sulphides, chlorides, nutrients, organic compounds and trace elements [11; 14; 15; 16]. When the concentration of toxic compounds (metal(loid)s) exceeds the concentration limits of the regulations, it is necessary to decrease environmental concentrations. Furthermore, compounds with a high value on the market could potentially be recovered to be commercialized [17; 18]. Hence, sediment component extractive technologies are strongly needed to enhance and promote beneficial uses [19]. Elevated metal concentrations in sediments are a crucial problem, due to their persistence in the sediments and potential negative effects on aquatic organisms [20; 21]. Metals such as Sn, Cu and Zn, and organotin compounds such as tributyltin (TBT) are often found in elevated concentrations in aquatic sediments [22; 23; 24]. These contaminants and especially metals emanate from natural and anthropogenic origins. Industrial pollution sources include shipping (including paints) and harbour facilities, agriculture, mining, and chemical factories [25].