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In Europe, large amounts of materials are dredged annually to maintain channels and harbour activities. Consolidation processes in dredged sediments take very long-time due to the high-water content, much more than those considered in the typical problems of geotechnical engineering. The electrokinetic treatment (EK) can be an effective technique to accelerate the dewatering of these sediments and, at the same time, to improve their mechanical properties. An experimental research is under course at the University of Napoli Federico II with the aim to analyse the effects induced by EK treatments on the physic-chemical and mechanical properties of two different soils. Some laboratory tests have been carried out in a special apparatus (special oedometer) adopting two different pore fluids (tap water and sea water). The laboratory results show that the effect of EK treatment, both in terms of induced water flow and improvement of soil mechanical properties, is affected by the chemical properties of the pore fluid and by the physical and mineralogical characteristics of the particles. The results obtained at the macro-scale (specimen) have been analysed at the micro-scale by means of X-ray diffraction analysis and Scanning Electron Microscopy, comparing the microstructures of treated and untreated soils specimens.