A study of the microflocculation-multistage filtration technology of mine water containing suspended solids

In order to solve the problem of difficult solid-liquid separation in the treatment of mine water containing suspended solids, based on the theory of nuclear crystal coagulation induced granulation, the process of “micro flocculation multi stage filtration” of mine water is studied through laboratory experiments. First of all, through the adjustment of reagent dosage and water conservancy conditions, the suspended particles and flocculants are induced to form a copolymer to form a floc settling time curve, and the floc granulation and densification are completed through the selection of optimal parameters. Secondly, four filter media of quartz sand, artificial zeolite, active carbon and aeolian sand are selected to investigate the effects of different media types and particle sizes on the removal efficiency of pollutants, and the physical and chemical reactions generated at the solid-liquid interface are analyzed. Finally, field tests are carried out in typical mines to verify the removal effect of the process on different pollution components. The results show that (1) the sedimentation time can be greatly reduced by adding polyaluminum chloride of 200 mg/L and diatomite of 200 mg/L in the micro flocculation stage. (2) The turbidity removal rate of 1−2 mm quartz sand in the multi-stage filtration stage can reach 97.9%, while the artificial zeolite in the four filter media is the best for the removal of inorganic ions. The removal rates of \rmSO_4^2 - , \rmHCO_3^- and Na⁺ in the filtered water can reach 25.5%, 44.1% and 69.9%, respectively. The micro flocculation multi-stage filtration process formed through the research results can greatly reduce the residence time in the process of mine water treatment and improve the solid-liquid separation efficiency. On this basis, the selection of natural diatomite as nucleating agent instead of polyacrylamide can effectively inhibit the generation of acrylamide monomer and reduce environmental risks. In addition, the process has a certain removal effect on inorganic ions. It is good application value for the treatment of mine water containing suspended solids.