Experimental study on improving the dewatering and drying performance of environment-friendly dredged sludge

Experiments were carried out employing a composite dewatering agent which is on the basis of ferrous sulfate (FeSO₄) as a dredging mud dehydant(hereinafter referred to as dehydrant), as well as using sand, slag, ash, lime, fly ash as sediment dredging dry amendments. The results show that, under the condition of dewatering agent dosage of 100 mg/L the precipitation efficiency could increase by 20%. The sludge specific resistance could decrease by 50%~70% by dosing dewatering agent with 5% of lime, fly ash, slag amendments, respectively, and the initial seepage rate could increase by 6%~68%. Compared with the original sediment, the bearing capacity of sediment which is using sand, slag, ash as amendments could increase by 30%~150% after four months of drying period. This research provides a feasible technical approach for the dewatering and drying of environment-friendly dredged sludge.