Properties of dredged material and potential scope of its beneficial use: A case study of the Pussur River in Bangladesh

Abstract

The Pussur River, an important river in Bangladesh, requires approximately 6 × 10⁶ m³ of sediment to be dredged per year. At present, this dredged material is mainly dumped on the nearby agricultural and fish-cultivation lands, causing a reduction in productive land and producing negative impacts on people's livelihoods. This study aimed to investigate the engineering and environmental properties of the dredged sand of the Pussur River and evaluate the viability of its potential uses in different sectors. Bed sediments from the Pussur River and dredged material from disposal sites were collected, and laboratory investigations were performed. The test results showed that the dredged material of the Pussur River mainly consisted of fine sand with a fineness modulus ranging from 0.58 to 0.72 and could be classified as poorly graded sand according to the Unified Soil Classification System. This sand was also found suitable for land development, with a fair to poor suitability rating. Given the low concentration of heavy metals (at uncontaminated/slightly contaminated levels), the dredged sand might be safely used for land reclamation, landfill cover, and horticultural purposes, or else for other geotechnical applications without further treatment. After washing/leaching, the dredged sand could also be used as a partial replacement for local sand in concrete works. Moreover, there is a possibility of exporting the dredged sand to Singapore and the Maldives as filling material. These findings will help policymakers design dredging projects with a proper spoil management plan accounting for the dredged material's beneficial use.