Influence of carbon source on the denitrifying phosphorus removal in A~2O process at low temperature

Abstract:

To enrich the nutrients removal pathway and investigate the influence of carbon source on denitrifying phosphorus removal at low temperature(10-12 ℃),a lab-scale A2O reactor was employed to study the process of phosphorus release and denitrifying phosphorus removal with sodium acetate,sodium propionate and their compounds as carbon source.At hydraulic retention time of 8 h,sludge recirculation ratio and inner recirculation ratio of 50% and 150%-250%,the differences of specific phosphorus release rate and the subsequent phosphorus uptake efficiency with different carbon source were obviously.The specific phosphorus release rate and the phosphorus uptake rate was 6.3 and 2.8 mg·h-1 with sodium acetate as substrate.However,the specific phosphorus release rate of sodium propionate and the compounds was 3.44 and 5.56 mg·h-1.The phosphorus uptake rate was 2.05 and 3.81 mg·h-1,respectively.On the other hand,the intracellular polymers synthesized by phosphorus accumulating organisms were varied with different carbon source.The content of PH2MV was improved by the sodium propionate which consequently increased the utilization efficiency of nitrate nitrogen by denitrification PAOs.The compounds of sodium acetate and sodium propionate were considered as the more suitable carbon source for denitrifying phosphorus removal of low temperature wastewater.