Removal efficiencies of dissolved organic matter and ammonium in coal mine water by coal gangue through column experiments

Good understanding of removal efficiencies of pollutants in coal mine water by coal gangue is of great signifi- cance to evaluate the coal mine underground reservoir technology and effective comprehensive usage of coal mine wa- ter. Column experiments at room temperature were carried out to study the removal efficiencies of dissolved organic matter (DOM) and ammonium in coal mine water by the filled coal gangue from the gob area of Bulianta Coal Mine. The results show that the removal efficiency of dissolved organic carbon ( DOC) is 64% after 6. 44 pore volumes (PV) effluents,which is related to the adsorption and biodegradation of DOC by aluminosilicate minerals such as kao- linite,muscovite,illite and chlorite in the studied matrix,which has low retardation capacity of aromatic compounds in the studied DOM. Meanwhile,the removal efficiency of ammonium decreases with time and amounts to 81% at the end of experiments,which is related to the limited adsorption capacity of kaolinite and illite in the matrix. The pH value of the effluent is higher than that of the studied raw water after 1 PV,which could be induced by the variation of hydro- lytic action of ammonium in the column. In addition,Oxidation-reduction Potential ( ORP ) of the effluent decreases obviously with time,indicating the enhancement of reducing environment and biodegradation ability.