The Study On Integrated Treatment Of HPF Desulfurizaiton Waste Solution And The Halogenation Wastewater

HPF desulfurization waste solution is generated in the process of desulfurization with HPF method in coking enterprises, which is toxic, difficult to deal with. The wastewater contains large amount of inorganic sulfide and a small number organics. If been released into the environment directly without treated, it will have an enormous impact on the growth of the animals and plants, even lead to death. In this paper, we respectively discussed the treatment methods of the main contaminants in the wastewater. The common methods mainly were physical methods chemical methods and biological method. According to the characteristics of the wastewater, a method of acid-oxidation combined process that we finally confirmed was used to treat the wastewater.Halogenation wastewater which is produced in the process of treating high strength phenolic wastewater with halogenation we have researched is of high acidity, The method to deal with the HPF desulfurization waste solution we have chosen needs large number of hydrogen ion, so we determine the technology of integrated treatment the halogenation wastewater and HPF desulfurization waste.In this paper, the HPF desulfurization pro-processing of wastewater with concentrated sulfuric acid was firstly studied, then we researched the treatment of remaining thiocyanate and phenol in the wastewater using concentrated sulfuric acid and sodium chlorate. The main conclusions are as follows:1) Concentrated sulfuric acid could treat the sodium thiosulfate of the HPF desulfurization wastewater, the acid actual consumption is much less than the theoretical one. When the final pH value of the solution is about3.24, the sodium thiosulfate has been processed. At the same time characterization of yellow precipitate is made by means of TG and XRD, it shows the yellow precipitate is many forms of elemental sulfur. The mass fraction of the total sulfur content reaches92.5%.2) Concentrated sulfuric acid and sodium chlorate have a good effect in removing thiocyanate and phenols in the wastewater, researches show that under the condition of low redox potential maintained by concentrated sulfuric acid and sodium chlorate, thiocyanate in the solution will polymerize and separate out in the form of brick red precipitate, at the same time a small portion thiocyanate will be removed in the way of hydrolyzation inevitably. The small part of phenols was halogenated and got out in the form of chloro-phenols. Besides according to analyze the TG, XPS, and XRD of brick red precipitate, we concluded that it is thiocyanate polymers containing a few chlorinated organic compounds.On the basis of the study, we used the halogenated wastewater as the hydrogen ion source to treat the HPF desulfurization waste solution, the results shows that:when the halogenation wastewater are mixed in three steps with the desulfurization waste solution at1:5.7in volume, the removal of sodium thiosulfatehas has been basically completed; Next, sodium chlorate and halogenated waste water oxidate waste liquid, after three times of feeding acid and sodium chlorate and reacting fully, concentration thiocyanate and phenol in the solution are0.851g/L and0.03g/L, the final COD value is2340mg/L, the three removal rate reach98.52%,97.06%and98.52%respectively; Finally we use fenton technology for further processing, the final COD value is57mg/L, the solution is colorless. In addition we did feasibility analysis of the joint process, the results show that the technology is not only simple and feasible, low investment cost.