Textural and morphological changes of dredged sediments after treatment techniques

The study aims to analyze and discuss the modifications of the physical and morphological characteristics of the contaminated sediments dredged in the Ravenna harbor after decontaminations treatments. To obtain adequate quality standards (as defined by ICRAM - APAT, 2007), the contaminated sediments were treated with different experimental techniques (soil washing and attrition cell). From the comparisons of the sediments’ characteristics before and after treatments, it appears that: sediments presenting the minor textural variations were only treated with soil washing that allows the separation of the sand fraction from the clay. The abrasion process, has only induced a slight increase of silt and clay clearly due to the abrasion of particles. The morphological changes of the particles due to the decontamination treatments have been observed using a Microscope Morphologi G3 Malvern and a digital optical microscope. Statistical analysis were performed to individuate the significant shape and dimensional parameters to describe the morphological alterations. The results highlight that the two treatments not causes a radical change of the particles morphology, though there are an alteration of the aspect ratio, circularity and intensity mean parameters but less the convexity parameter.