Comprehensive Treatment Of Wastewater With High Salinity And High Fluorine

The fluorine is one of the necessary elements for human healthy. However, excessive fluoride contained in the supplied water can result in dental or fluorosis. The limit for fluoride in drinking water standard is l.Omg/L in china. Sewage synthesis emission standard (GB8987-1996) of fluoride first-level emission standard is no more than lOmg/L. The waste water of fluorine always has the high salt issue and because of the2problems, it is difficult to treat the waste water properly.High fluorine and salt waste water is the main pollution in the production of fluorine chemical industry, and the pollution issue is of widely concerned. In this paper, it is studied on comprehensive treatment of high fluorine and salt waste water, especially with the method of chemical coagulation precipitation and evaporation crystallization. The pilot design and real running are done after all the key parameters are determined. From the study we can see that, by adding CaCl2solution in2stages, the content of fluorine can be decreased as low to20mg/L which can meet the second-level emission standard. In the meanwhile, the vacuum evaporation crystallization process was optimized experimentally, with the effecting parameters being seeds adding, evaporation speed, pH of solution, and etc. And with the optimized operation condition of crystallization, the expected results are derived from the pilot facility. The result of this study will lay a base for the design and operation of the commercial equipment.