Study on the effect of coagulation treatment on dissolved organic pollutants in coal mine water

The inlet and outlet water of coagulation unit treating coal mine water were physically graded by membranes with different pore size, and three-dimensional fluorescence spectroscopy peak-seeking method and fluorescence area integration method were used to analyze the dissolved organic compounds in the inlet and outlet water of coagulation unit, in order to explore the impact of coagulation and precipitation treatment on the composition of dissolved pollutants in mine water. The results showed that the coagulation treatment effect was optimal under the condition of PAC dosage of 350 mg/L. The colloidal dissolved organic matter(1 nm-0.45 μm) in coal mine water could be basically removed by coagulation and precipitation (removal rate of 97.78%), which involved colloidal dissolved organic matter, including fulvic acid, microbial metabolites, and humic substances. Dissolved organic matter(<1 nm) of the solution state in mine water was still retained in full in the coagulation effluent, mainly including aromatic compounds and fulvic acids. In addition, overdosing of coagulants would lead to an increase in COD in effluent, which was attributed to the inactivation of excess PAC, leading to an increase in the concentration of reducing inorganic ions in the water.