Research On The Efficiency And Mechanism Of Denitrification For Phenol Contained Wastewater Using SBR Process

Coking wastewater containing high concentrations of phenol cyanide is one of the major industrial sources of pollution at present. It is difficult to deal with because of its complex and ingredient and high toxicity. This experiment systematically studied the degradation of phenols and ammonia nitrogen using artificial SBR wastewater treatment process treating the mixture of seven phenols and ammonia. The optimum operating parameters of SBR process wastewater containing phenol were optimized by exploring degradation of phenols and ammonia under different conditions. The inherent law of phenolic compounds inhibiting nitrification was also analyzed using three-dimensional fluorescence spectroscopy and infrared spectroscopy to deal with the situation at all stages of the reactor for more comprehensive studies.In the reactor start-up phase, the concentrations of influent phenolic pollutants, COD and ammonia were200mg/L,454mg/L and about22mg/L. The value of pH was8and the reaction temperature was20℃. The reaction period was12h. The removal rates of phenolic pollutants and COD with activated sludge were up to99%and90%, respectively, while the removal rate was only55%. In the start-up phase, the concentration of phenolic pollutants in influent increased to500mg/L, and concentration of COD and ammonia were1141mg/L and57mg/L. The phenol and COD removal efficiency was down to about30%, and a great nitrification inhibition also happened. With the growth of time, inhibition of nitrifying bacteria by activated sludge decreased gradually.The concentration of phenolic pollutants, COD and ammonia in influent were500mg/L,1141mg/L and57mg/L. The value of pH was8and the reaction temperature was20℃. The reaction period was12h. The sludge concentration increased to4g/L, the respectively phenols and COD removal increased to about99%and90%. But the removal of ammonia remains at about35%. The concentration of sludge is an important factor affecting the removal of organic sludge performance. However to improve the dissolved oxygen concentration and alkalinity were not effectively change the improvement of ammonia nitrification inhibition. Effluent ammonia removal rate was still only about50%, representing great inhibition of bacterial activity of nitrification in the reactor. When all other conditions remain unchanged, the hydraulic residence time increased2hours, with a total length of up to14hours, removal efficiency of phenols and COD remained at around99%and94%. While the removal efficiency of ammonia increased from50%to about80%. After analysis of material for water, hydroquinone is converted to be the major inhibitor of nitrate.Analyzing SBR reactor for a period, the concentration of phenolic pollutants, COD and ammonia in influent were500mg/L,1141mg/L and57mg/L. The removal rates of COD, phenols and ammonia were up to96%,99%and85%, organic matter has been almost completely removed after the completion of the water1.5h (2h time point). Accumulation of nitrite reached the peak of8.56mg/L, while nitrate nitrogen was almost completely consumed. After aeration of3h (3.5h time point), almost all of the nitrite transformed into nitrate as the concentration of nitrite nitrogen and nitrate nitrogen were0.2mg/L and13.8mg/L. Phenol fluorescence disappeared in effluent (0.5h time point) at the end using three-dimensional fluorescence spectroscopy, indicating that phenols was almost completely absorbed by the activated sludge at this time. In sedimentation and drainage phase, the fluorescence intensity of the extracellular substances decreased by gravitational settling.