Rates of sulfate reduction and metal sulfide precipitation in a permeable reactive barrier

摘要: Abstract A full-scale reactive barrier, utilizing bacterially mediated SO4 reduction to promote metal sulfide precipitation and alkalinity generation, was installed in August 1995 at the Nickel Rim mine site near Sudbury, Ontario. Monitoring of groundwater chemistry over a 3-a period allows assessment long-term barrier performance. The overall rate removal within declined with time by 30% from an initial 58 40 mmol l−1 a−1 38 months after installation. Over same time, Fe 50% 18 a−1. degree is both spatially temporally variable. Spatial differences are primarily result different residence times due hydraulic conductivity variations treatment material. Temporal likely decline organic C availability reactivity seasonal reduction. Temperatures aquifer fluctuate low 2 °C winter high 16 °C summer nearly twice as great rate. An effective activation energy (Ea) kJ mol−1 can account for temperature-induced changes. In Year 3, removed >1000 mg/l >250 Fe, demonstrating viability this remedial approach.