Effects of NaCl on fine sediment flocculation and settling in still water

摘要

Physical content is one of teh primary factors that influence muddy water infiltration rate. And electrolyte in the water plays an important role in sediment flocculation and settling. Sediment concentrations of 5, 10, 20 g/L are prepared with NaCl solutions of concentrations between 0 and 30 mmol/L. The sediment loading water is sampled with a 20-mL pipette, and then relative sediment concentrations are determined thereafter. The results showed that NaCl has a critical concentration for sediment flocculation, which decreases with the increase of original sediment concentration. The critical particle size to flocculate is 0.027 mm. The relative sediment concentrations at the same water depth decrease exponentially with time, and teh median settling velocity #omega#_(50) increases with the increase of both NaCl and original sediment concentrations.