90 / 2023-12-29 23:47:16

Model experimental study on artificial nitrogen injection to enhance sulfate removal in goaf mine water

simulation experiments,high sulfate mine water,artificial nitrogen injection,sulfate reducing bacteria

Coal mining activities result in a large amount of mine water inflow, leading to groundwater pollution, and after mining, a significant number of abandoned goafs are left behind. Indoor simulation experiments have shown that the collapsed coal and rock in the goaf can effectively treat mine water with high sulfate and high suspended solids under strong reduction conditions. This study constructs a similar simulation physical model that achieves geometric similarity, lithological similarity, fracture rate similarity, and water source similarity with the collapse zone in the goaf of an actual coal mine.The study investigates the reduction effect of turbidity and sulfate in the goaf mine water under artificial nitrogen injection conditions. The results demonstrate that within 120 days of the experiment, the sulfate reduction rate in the mine water can reach 20%, and the turbidity reduction rate can reach 80% with artificial nitrogen injection. Analysis of microbial diversity in the liquid and solid phases shows a significant increase in the abundance of sulfate reducing bacteria (SRB) in both phases after artificial nitrogen injection. The solid phase exhibits a SRB abundance of 35%, while the liquid phase shows a SRB abundance of 25%.Correlation analysis reveals that the sulfate content in the mine water is positively correlated with the dissolved oxygen content, inversely correlated with the abundance of SRB, inversely correlated with the duration of artificial nitrogen injection, and inversely correlated with temperature. These findings provide evidence that artificial nitrogen injection enhances the sulfate removal effect in the goaf mine water.The research results have theoretical relevance and provide data support for the pre-treatment of underground mine water in Chinese coal mining areas.