Beneficial Use of Contaminated Sediments: Critical Review of Treatment Technologies.

Abstract

Rising costs and decreasing availability of disposal sites for contaminated dredged materials necessitate exploration of alternatives to disposal, such as using the dredged material in a manner that serves another purpose (ie, beneficial use). To make dredged materials compatible with an intended beneficial use, it is often necessary to first treat the materials to reduce the concentrations, toxicity, and/or mobility of contaminants. This review evaluates existing and emerging treatment technologies that support beneficial use of dredged materials and identifies factors that influence their success and limitations. This review focuses on recent publications on ex situ treatment technologies, including solidification and stabilization technologies, extraction treatments, and bioremediation. Most studies on the efficacy of treatment technologies have been conducted at the laboratory- or pilot-scale, and the heterogeneity of contaminant concentrations and the physical characteristics of dredged materials strongly influence the effectiveness and efficiency of treatments. Many recent studies describe the combined use of two or more treatments. One outcome of this review is a database of projects in which dredged materials were treated to facilitate beneficial use of contaminated sediment. Few sources reported details on the full life cycle of projects, costs and benefits, timelines and durations, contaminant concentrations in dredged and treated materials, regulatory thresholds and acceptance, or the basis for selecting beneficial use applications. To address this data gap, the creation of a data platform to share information and promote knowledge and data sharing of the salient details is recommended through partnerships with permitting agencies and practitioners.