Cost-effective disposal is a major concern for sediment remediation projects that require removal of sediments. To meet landfill criteria sediments must pass tests for hazardous waste content, hazardous waste leachability and residual moisture content. A knowledge of these parameters is essential before the cost of the remediation can be estimated. CRA has developed a laboratory treatability study procedure to obtain the required information rapidly. An example of the application of this procedure is a treatability study that was conducted on heavy metal contaminated dredged sediment from a site in Michigan Three sediment samples were obtained and composited to form a sample that would be representative of site conditions. To be acceptable for disposal at a non-hazardous waste landfill the sediment samples must pass TCLP, stability criteria, and the paint filter test. Sediment leachate data showed that the sediment met only TCLP criteria, therefore stabilization was necessary. Ten polymers were evaluated for their effect on solids settling. A sediment slurry was settled with and without polymer treatment and the supernatant and settled solids were collected. A filter press was used to dewater the settled solids to produce a filter cake, which was tested for water content, TCLP metals, and the paint filter test. The effects of solidification agents on the settled solids were also evaluated. The agents tested were Portland cement, fly ash, and cement kiln dust. The results showed that untreated settled solids did not meet landfill stability requirements. The ability of polymer treatment, solidification and filter cake from dewatering using a filter press to meet the landfill stability requirements will be described. Based on the results of the treatability study a cost-effective technique for sediment treatment and disposal was determined.
Balba, M.T; Dore, S.; Pope, D.; Smith, J.; and Weston, A.F.
"Use Of A Bench-Scale Treatability Study To Determine Cost-Effective Disposal Methods For Contaminated Sediments,"
Proceedings of the Annual International Conference on Soils, Sediments, Water and Energy:
Vol. 11, Article 22.
Available at: http://scholarworks.umass.edu/soilsproceedings/vol11/iss1/22