Study on Engineering Characteristics and Environmental Risks of Lagoon Sludge Modified Soil
In order to achieve the harmless treatment and resource utilization of typical lagoon sludge,the sludge from Xiaohai Lagoon in Wanning City,Hainan Province was selected as the research subject.A soft soil curing agent,prepared from bulk industrial solid wastes such as blast furnace slag,steel slag,and industrial gypsum,was employed for sludge stabi-lization.The results demonstrated that the soft soil hardening agent enhanced the compressive strength,shear strength,and liquid-plastic limit of lagoon sludge while reducing leaching concentrations of heavy metals and their migration/release capacity.Additionally,it improved seed germination index to meet construction land backfill strength requirements and safety standards for garden greening soil.SEM and XRD analysis revealed that silicon and aluminum components in original lagoon sludge participated in hydration reactions under an alkaline environment provided by alkaline activators,steel slag powder and mineral powders.This resulted in numerous holes on the modified sludge surface along with stable crystallites(such as rods,flakes)and hydrated gel state products within a compacted internal structure with en-hanced intergranular connections.Consequently,engineering characteristics of lagoon sludge significantly improved af-ter being treated with a soft soil curing agent while effectively solidifying/stabilizing heavy metals present in the sludge to mitigate environmental/ecological toxicity.
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维普
