The global warming potential of the plant was 1.86 kg CO 2 eq/m 3, to which limestone dissolution contributes 94% of the total value, and hence the replacement of non-carbonate alkaline materials would significantly decrease the emissions to the atmosphere. The replacement of wood chips by forestry waste would reduce emissions by between 50% and 100%. Thus, the replacement of certain material sources and circular usage would lead to a significant decrease in impact values. The results also show that the potential impacts of the plant are closely related to the upstream production chain of the materials employed in this technology. We show that although the construction of the plant initially creates significant environmental impacts, these become negligible within a few years (4.5 years). The main goal of this study is to perform the first life cycle assessment for dispersed alkaline substrate technology, effective for metal-rich and acid waters, in order to determine the environmental impacts generated throughout its entire life cycle and the factors controlling the environmental performance of this technology. Life cycle assessment is a proven methodology that can help in the selection of the best available technology by reducing environmental burdens while ensuring the efficiency of the treatment.
Although the choice of remediation systems is usually dictated by technical and economic factors, the sustainability of such systems is becoming increasingly important in decision making, and efforts to promote greener remediation measures are being made. Historical mining activity in the Iberian Pyrite Belt has left a huge number of abandoned sites these cause severe water pollution by acid mine drainage, for which remediation seems to be unaffordable.