An amendment strategy for enhancing the performance of geotextile tubes used in decontamination of polluted sediments and sludges

Geotextile tubes have potentially a major application for the decontamination of pollutant-bearing sediments and sludges. Two major technical issues that may cause ineffectiveness of the remedial operations are (i) the inability to retain organic and inorganic pollutants that are dissolved in the water phase, and (ii) the slow dewatering process due to rapid formation of a filter cake by colloidal particles on the inside of the fabric. In this study, we are adding various reactive materials to the sediments and sludges so as to transfer soluble pollutants to the solid phase. The reactive materials we have selected are activated carbon and charcoal for immobilizing organic pollutants, and phosphoric rock for precipitating heavy metals. Our preliminary design indicates that adding a small fraction (0.5 wt%) of charcoal can cause an order of magnitude reduction of aqueous phase concentrations for many EPA-prioritized organic pollutants, and that a small quantity of phosphoric rock added can reduce aqueous phase concentrations of lead, zinc, copper, etc., to their respective EPA drinking water standards. This paper is a research-in-progress report. Detailed experimental work for optimizing engineering design of such amendments is currently being undertaken and the results will be presented shortly. Copyright ASCE 2005.