Recovery of dredged material for beneficial use: the future role of physical separation processes

Abstract

Sediments dredged from navigational waterways have historically been disposed in confined disposal facilities (CDFs) or in open water. When sediments are contaminated, open water disposal is typically not an alternative, and sediments are placed in CDFs. Many CDFs are nearing capacity, and siting and constructing new facilities is both difficult and expensive. In many cases, CDFs contain both clean and contaminated dredged material. Removal of materials suitable for beneficial use (BU) is one alternative under consideration to extend the life of existing CDFs, as is separation of recoverable materials at the time of disposal. Several technologies for recovery of clean materials or treatment of contaminated materials for beneficial use are presently under evaluation. Physical separation technologies have been demonstrated to have potential in reducing the volume of sediment that must be managed with confined disposal, but there are several technical issues that remain to be addressed. Determination of beneficial use specifications, physical and chemical characterization of dredged material, overall site characterization, selection of suitable unit operations, management of liquid and solid residuals, and cost/benefit analysis, are all important aspects to successful implementation of separation processes. Several of these elements are presently being evaluated in research conducted by the US Army Corps of Engineers, at the ERDC Waterways Experiment Station (WES).