passive treatment of acid mine drainage by investigating the efficiency of different material layers in Songon, Tabriz, Iran

Acid Mine Drainage (AMD) is considered the most significant environmental issue in mining, negatively affecting the quality of surface and groundwater. In this study, the Songon Copper Complex was selected as the mining site, which produces approximately 11 million tons of waste annually. The presence of sulfide waste and climatic conditions make the generation of acidic drainage unavoidable. To analyze the quantity and quality of acid drainage, nine sampling periods were conducted at the waste dump outlet. a laboratory-scale with two layers include organic and mineral material was studied for the treatment of simulated AMD from Songon mine is the largest open-cast copper mine in Iran. The experiments involved six different mineral scenarios (mushroom compost, humus, and wood shavings) along with organic substrates (zeolites and limestone). These were conducted under identical conditions in successive alkalinity producing systems (SAPS) columns, each with varying hydraulic retention times (4h, 24h, 48h, 120h, 144h, and 240h). Every effluent was examined and removal efficiencies were computed for pH, acidity, sulfate, manganese, aluminum, and copper. Wood shaving material was recognized as the best performance between organic layers with 81.04% overall removal efficiency and for alkaline layer, limestone was found the best performance with 87.7% overall efficiency. The selection of limestone as having the highest removal efficiency is based on its lower price and greater availability compared to zeolite. Keywords: Acid mine drainage (AMD), Heavy metals, Successive alkalinity producing systems (SAPS), passive treatment technology