Application of tubular microfiltration membrane in hardness and silicon removal of high saline water
In response to the problems of traditional high saline wastewater treatment using the"membrane concentration+evaporation crystallization"method,the softening,desilicontion,and turbidity removal steps of high saline water zero discharge system pretreatment were studied,and it was pointed out that compared with traditional pretreatment methods,tubular microfiltration membranes have significant advantages.Taking the Menkeqing Coal Mine and Xiaojihan Coal Mine projects as examples,the process system was studied through small-scale and medium-sized tests,using a tubular microfiltration membrane(TMF)instead of a clarification tank for solid-liquid separation.The application results show that under the conditions of calcium ion concentration of 712.5 mg/L,magnesium ion concentration of 110.4 mg/L,and total silicon(calculated as SiO2)content of 120 mg/L in the influent,by adding sodium metaaluminate,calcium chloride,magnesium chloride and other agents for coagulation,the SiO2 removal rate is no less than 95% using tubular microfiltration membrane for solid-liquid separation;and the effluent meets the requirements of calcium ion concentration within 10 mg/L,magnesium ion concentration within 10 mg/L,and total silicon(calculated as SiO2)content within 10 mg/L,and meets the requirements of turbidity within 1 NTU and SDI within 5 for reverse osmosis influent.The operating cost is saved by 10%～20% compared to the original process.
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