Research On Nitrogen And Phosphorus In A₂N System Based On The Molecular Weight Distribution Of Sewage Carbon Source

For low C/N sewage treatment, how to improve the utilization rate of carbon source of sewage itself to improve the efficiency of the technology of denitrification and phosphorus and recognizing the mechanism of transformation and utilization of organic matter has become a research hot spot in today’s water treatment field.This study is based on the A2N process, in-depth study of the relationship between wastewater in anaerobic, aerobic, anoxic period of pollutant removal with organic changes and the molecular weight distribution, further understand the DPB function mechanism of denitrifying phosphorus removal and sludge with different size, the use and transformation of organic matter in A2N system.The results show that:(1) Due to DPB of anaerobic period utilization and adsorption of the organic matter in sludge of sewage, in and out of the water organic molecular weight distribution altered obviously.Test show that the particulate organic matter decreased by19.19%,0.45μm～0.08u sections organic matter decreased by75.10%, but less than1k increased from24.57%to45.92%of DOC.(2) DPB sludge in anaerobic period of release phosphorus efficiency is closely related to the sewage of low molecular weight organic matter content, the concrete in the<1k was most pronounced on the low molecular weight organic compound section of performance, and had no significant relationship with more than5w, and shows that the smaller molecular weight, DPB could easily release phosphorus sludge utilization.(3) After aerobic treatment, the water average removal rate of COD is50.16%; the average removal rate of NH4+-N is50.16%.Combined with changes of aerobic period in and out of the water organic molecular weight distribution, found<3k of organic matter concentration has obvious effects on nitration, especially<300organic matter concentration is too high will direct inhibition of nitration, while0.45μm～10w,5w-lw segment of organic matter concentration increase the nitration does not have a significant impact.(4) DPB sludge of anoxic period using its carbon source denitrification and phosphorus removal simultaneously, the average removal rate of TP was81.29%, the average removal rate of NO3--N was86.43%.Due to the return sludge carried with and their release, the effluent organic matter of anoxic period more than water6.9mgTOC·h-1. Test showed that the increase in<1w organic matter, especially in the lk-500section of the most obvious increase, from6.9%of DOC increases to37.35%. Show that nitrogen and phosphorus is of small molecule organic compounds using rate is less than its formation rate.(5) According to molecular weight of organic matter in raw water cutting experiment test, found that nearly70%of the sewage of macromolecular organic matter of particulate organic matter, and the rest of the DOC in the molecular weight of0.45μm～300on interval distribution of U, of which>10w,<1k of the organic matter, respectively accounted for36.76%,45.18%of DOC.A2N process as a whole the average removal rate of COD、NH4+-N、TN and TP were85.80%、85.87%、74.47%and89.04%respectively. Contrast process changes in and out of the water organic molecular weight distribution, the removal rate of the TOC was92.94%, the particulate organic matter removed73.02%of the total removal rate, In DOC distribution,1w～5k、500～300、<300of organic matter vulnerable to microbial utilization, especially DPB sludge use<500organisms accounts for73.47%of the total variation, suggests that this organic matter affects technology plays a significant role in nitrogen and phosphorus.