Experimental Study on Simultaneous Nitrification and Denitrification in Municipal Wastewater

The influencing factors of simultaneous nitrification and denitrification (SND) was investigated in this study. The experiment was carried out with synthetic wastewater in Sequencing batch reactor (SBR). Some effect factors and mechanism of SND were studied through continuous running of SBR process. Optimum operation condition of SND was obtained in the experiment, and it was found that the removal efficiency of COD and TN reached 90% and 83%~95% respectively when influent CODCr concentration of 200~300mg/L, NH3-N of 25~35mg/L, TN of 40mg/L with temperature of 18~25, C/N ratio of 12, and DO in the range of 0.5~1.5mg/L. Further more, SND can overcome the phenomena of insufficient alkalinity in wastewater, and that alkalinity yield by denitrification can fill up descend of PH value, which resulted in the degradation of organic and nitrogen compounds via microorganism. Thus, simultaneous nitrification and denitrification can be achieved by SBR process at normal temperature.