Geotextile tube dewatering of contaminated sediments, Tianjin Eco-City, China

An account is given of the use of geotextile tubes to dewater dredged contaminated sediments at the Tianjin Eco-City site in China. Approximately 5 million m3 of contaminated sediments from the bed of a lake were dredged and dewatered in this way with the effluent water returned to the lake. The dewatered solids were utilized within the project site, or were disposed of in a landfill, depending on their degree of contamination. The paper details the tube dewatering evaluation process undertaken and presents the results on which the dewatering facility was designed. To enable an assessment of the full-scale dewatering performance various relationships were derived based on a conservation of mass of the dewatering process. The design, construction and operation of the dewatering tube facility for the treatment of the moderately contaminated sediment waste stream is also presented.