Volume 6, Issue 6 (June 2009)
Evaluating Management Options for the Disposal of Dredged Sediments
This paper presents a screening framework that evaluates management options for the disposal of dredged sediments on the basis of chemical and toxicological characterization tests. The paper provides a combined brief overview of disposal options for dredged sediments and relevant testing, together with simplified decision rules for the feasibility of each option. The framework provides for two stages of assessment. In Stage I, disposal in open waters is evaluated based on the combination of results from chemical and toxicological analyses, supplemented by physical characteristics of sediments. For sediments that do not meet requirements for open-water disposal, Stage II evaluates the suitability of disposal in landfills or in confined facilities, upland and underwater. Decisions in Stage II are facilitated by well-established effluent criteria applied to ambient water and wastes admitted to landfills, as well as by calculations estimating the impact of sediment contaminants to the vicinity of the subaqueous confining structures. The application of the decision-making methodology is demonstrated using test results from sediment samples from Piraeus Harbor, Greece, and Indiana Harbor, IL, USA. Results showed that the framework is able to discriminate well among sediments from different subareas to be dredged. Disposal to open water is not feasible for most contaminated sediments from areas with increased shipping activities. Disposal in confined facilities (subaqueous or upland) proved to be a viable option for most of the sediments, whereas all sediments were characterized as nonhazardous and can therefore be accepted in an ordinary landfill.