Solids Separation Systems

Increasingly stringent restrictions on placement or disposal of contaminated dredged material and enhanced interest in finding ways to beneficially use dredged material have drawn attention to alternative management strategies, including the use of innovative treatment technologies to remove or destroy contaminants.

Clean dredged material has the potential for a wide range of beneficial uses—the sandy fraction in particular. Contaminant destruction technologies, common to environmental remediation projects, have generally proven to be complex and too expensive for navigation dredging projects, where dredged material volumes and production rates are high and lower-cost disposal alternatives are usually available.

Treatment technologies developed or adapted for removal of contaminants from sediment include physical separation, soil washing, solvent extraction, and thermal processes. Of this group, physical separation perhaps offers the best chance for cost-effective application to maintenance dredging projects; contaminant reduction is achieved by segregation of the most contaminated sediment fractions, rather than by contaminant destruction. Because contaminants are not destroyed by separation processes, careful material characterization is required to inform  equipment selection in order to successfully achieve processing objectives.

 Physical separation technologies are designed to separate sediment into different size or density fractions based on differences in their physical properties. In some cases, physical separation produces the additional advantage of separating contaminants attached to sediment particles into a dirty fraction while also producing a clean fraction for potential beneficial use. 

One example of the solids separation process.  Each dredging site has unique needs.