The Research On Denitrifying Effect Of Different Carbon Source And C/N

The paper was focus on the degradation of nitrogen and carbon sources of sodium acetate and yellow water under the different conditions, including the carbon to nitrogen ratio were 3.4,4.5,5and3,4.1,5.3,6.1,6.6 and 7.3in the lab-scale SBR reactor. In addtion, this research compared the denitrification velocity and denitrification characteristics under different carbon sources and found the optimal C/N, based on the parameters calculated by the dynamic model of Monod equation. In the activated sludge domestication, compared the configuration of sludge with that of inoculation and analyzed different sludge yields. Through analyzing the techno-economic indicator of sodium acetate and yellow water, the research made a comparison between the advantages and disadvantages of both carbon sources to put forward the technical reference to the Long Wangzui treatment's upgrade reform. The conclusions were as below:1. The reaction time was relatively shorter when denitrifying bacteria utilized sodium acetate as carbon source. When the system first received sodium acetate as carbon source, it reacted quickly in 1-2 days with high utilization rate.2. When the carbon source was sodium acetate, and C/N were respectively 3.4,4.5 and 5, the nitrogen source removal rate increased with the rising of C/N which are respectively 45.9%-80.0%,82.5%-99.5%,98.6%-100%in 60 min. Although when the C/N was 4.5, the removal effect was good, the removal effect was fluctuate. But the real HRT of treatment was shorter than 80 min, so the nitrogen resource was not allowed to reduct. So the optimal C/N was 5 when ultinizing sodium acetate as the carbon resource.3.When the carbon source was yellow water, and C/N were respectively 3,4.1,5.3,6.1,6.6 and 7.3, the removal rate of nitrogen source was related with C/N and degradation time. When C/N reached to 5.3,30 min later, the denitrifying effect would not be changed with C/N increased, and nitrogen removal rate was above 95%. But when C/N continued to increase, denitrifying rate was faster, and the denitrification time of the system shortened. Considering the denitrifying rate and economic factors, this study suggested that when the carbon source was yellow water, the optimal C/N was 5.3.4. Denitrifying process was simulated based on the Monod equation. When the carbon source was sodium acetate, the denitrifying kinetic parameters were that Vmax No3 was 0.706 gN/VSS-d, Vmax NO2 was 0.241 gN/VSS·d, KsNO3 was 4.8, and KsNO3 was 3.4, the maximum curve fitting fitness reached to 0.3829; when the carbon sources was yellow water, denitrifying kinetic parameters were that Vmax NO3was 0.4-0.5 gN/VSS-d,Vmax NO2 had a large variation, KsNO3 was 4.8-4.9, and KsNO3 was 4.4-4.5.5.When the carbon source was sodium acetate in system, the denitrifying bacteria were mainly spherical and YD was 0.4-0.41 mgVSS/mgBOD, while when the carbon source was yellow water the denitrifying bacteria were mainly short rod and spherical and YD was 0.51 mgVSS/mgBOD.