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GeoAmericas - 2020
Abstract: 103-1

103-1

Metal fate during geotextile dewatering of a contaminated sediment

Authors:
MASc1, C.B Lake1, Dr.2
1 DALHOUSIE - Dalhousie University, 2 ACADIA - Acadia University

Abstract:

The use of geotextiles in sludge dewatering applications has become a popular approach for many engineering projects. For contaminated sediments, the water quality of the resulting effluent is important to quantify as it affects decisions on secondary treatment of effluent. The purpose of this paper is to discuss results of bench scale studies performed for a large-scale remediation project in Nova Scotia, Canada in which geotextile tube dewatering is one of the options for dewatering the contaminated, fine-grained sediment prior to containment. Selected metal concentrations in the sediment are elevated relative to guidelines. The purpose of this paper is to examine metal concentrations in geotextile filtration effluent during gravity dewatering tests at the laboratory scale. The sampling program of the contaminated sediment is briefly described as well as the results of various physical and chemical characterization tests performed on the sediment. The results of rapid dewatering tests performed with the sediment conditioned with a polymer is presented. Characteristics of the resulting filtrate (metals and particle concentrations) and filter cake is presented in the paper with a focus on the primary elevated metals in the sediment (Zn, Pb, and Cu). The distribution of these metals in the filtrate in terms of total versus dissolved concentrations is also presented and compared with particle counts in the filtrate to better understand the mobility of these metals during geotextile dewatering.

Keywords:
 dewatering, geotextile, remediation, sediment, treatment