Salt Removal In High Salt Organic Wastewater Treatment Research

With China’s expanding industrial scale, high concentrations of salt in the wastewater pollutant is becoming more and more complex. Wastewater of high concentration of soluble inorganic salt and difficult degradation of toxic organic matter will cause serious environmental pollution and damage to soil, surface water and groundwater and surface water. At present, the traditional method of desalination time consuming, high operation cost, more constraints, the characteristics of supercritical water oxidation technology in dealing with this kind of high removal rate of organic wastewater with high salt, reaction speed, no secondary pollution, etc, but increased salinity or contains a lot of chloride ion in waste water, can make the SCWO reactor blocking and corrosion, finally forced SCWO equipment downtime, cleaning, assembly, pressure testing and restart, the serious influence the operation reliability and economy of SCWO device. In this paper, the main research content is:(1) under subcritical conditions, laboratory configuration of 10% and 5% sodium chloride, sodium sulfate and calcium nitrate solutions, using the control variable method, respectively, to study the effect of temperature and pressure on its solubility.(2) with the method of preparation classes of hydrotalcite, by controlling the divalent and trivalent metal cation and anion formula and parameters of control to remove chloride ion to search for the optimal condition, to determine the optimal parameters.Under the optimal parameters for practical wastewater treatment will be as much as possible to minimize cost, to the better popularization and application.Research shows that:(1) under subcritical conditions, by controlling the temperature and the pressure inside the reaction kettle, with different concentration of NaCl and Na2SO4, calcium nitrate solution for processing, collection, water kettle bottom residual liquid and emptying valve of water, the final determination of the concentration of salt.Three kinds of salt are under the condition of high temperature and low pressure to obtain the optimal parameters: at 350 ℃, 5 mpa, the removal rate of 83% NaCl, peak;At 350 ℃, 4 mpa, Na2SO4 removal rate was 92%, the peak;At 350 ℃, 7 mpa, Ca(NO3) 2 removal rate of 62%, a peak.(2) under laboratory conditions, the use of calcium hydroxide and sodium aluminate and chloride ions to form water insoluble sediments Ca2Al(OH) 6 Cl, removing the effect of chloride ion in order to achieve.Under the optimal conditions for a power plant in shanxi high chloride waste water processing, the results show that the Ca2 + : Al3 +, Cl- mole ratio for 10:4:1, adding the way 1:2, chloride ion removal rate as high as 90%;Experiments of Ca2Al(OH) 6 Cl metal in waste water of actual Mn removal rate as high as 99%.