Evolutionary Behaviors of Straw-Reinforced Slurry for Sustainable Management of Dredging Sediment: Rheological and Fertility Properties

Abstract

Abstract This study evaluates the potential of using rice straw waste as a sustainable alternative for managing the dredge sediment. The rice straw was used to reinforce the dredge slurry to realize “treating the wastes with wastes”. The dredge slurry could be relocated with enhanced rheological properties or reclaimed cultivable land by in-situ management. In this framework, the rheological and fertility properties of straw-reinforced dredge slurry were investigated with a 90-day degradation period. The increased liquid limit and fine content were observed regardless of the straw content and degradation time, and a decreased slump flow and increased dynamic viscosity were obtained after the addition of straw. Nutrients, including SOC, TN, P, and K, increase over time after straw reinforcement, suggesting effective land reclamation by straw blending. The increases were abrupt in the first 14 days, followed by a gently increasing rate. Soil pH decreases over time to the range more suitable for planting. Results suggest that effective straw reinforcement enhances the rheological properties for relocating and improves the soil fertility for in-situ tillage. This study supplements the societal image of dredge materials and waste straws in engineering and environmental applications.