Compare Of Enrichment And Metabolism Characteristics Between Denitrifying Phosphorus Removal Bacteria And Traditional Phosphorus Accumulating Organisms

This study compared the sewage treatment effect of anaerobic/anoxic sequencingbatch reactor (A/A-SBR) and anaerobic/aerobic sequencing batch reactor (A/O-SBR)and analyzed N2O emission mechanism and differences. The main research contentsand results were as follows:The effect of propionic/acetic acid ratio, aeration intensity and pH were focusedon conventional A/O-SBR process for phosphorus and nitrogen removal, biochemicalmechanism of nitrogen and phosphorus removal efficiency were discussed from theaspects of the transformation of COD, SOP, TN, poly-β-hydroxyalkanoates (PHA),glycogen and the dehydrogenase activity. According to the above investigations, theproposed conditions suitable for growth and mechanism of phosphorus accumulatingbacteria (PAOs) were determined finally.A systematic study on the main influencing factors of denitrifying phosphorusremoval (A/A-SBR) were carried out, The SOP removal efficiency of the systemachieved better level when the C/P ratio was controlled at22, sludge age was15d andNO3--N concentrations was45.5mg/L.With the increase of propionic acid content,SOP and TN removal efficiency both decreased, however N2O produced rateincreased gradually, which showed that high acetic acid content as the carbon sourcewas more suitable for the denitrifying phosphorus removal system. A linearrelationship was found between PHA and volatile fatty acids (VFA), there existedexponential relationship between nitrogen, phosphorus removal and PHA in anoxicdenitrification phase, anoxic PHA changes directly affected the phosphorus absorptionrate and nitrogen removal rate. A good combination was found between the nitrogenand phosphorus removal and the variation of polymer in the system, which bothqualitatively and quantitatively revealed denitrifying phosphorus removal sludgecharacteristics and denitrifying phosphorus removal effect regularity, furthermoreexplained the phenomenon of denitrifying phosphorus removal logically.The research showed that the removal efficiency of COD and SOP by the normalA/O-SBR nitrogen removal process were higher than the A/A-SBR denitrifyingdephosphatation process, which was attributed to the PAOs characteristics of highproductivity aerobic respiration and its inherent species. While a high TN removal rate was found in the A/A-SBR system due to high denitrification efficiency, andaccompanied by higher N2O yield and conversion rate, the accumulation of largeamounts of NO2--N and low content of initial PHA in the anoxic denitrification phasewere the main reason. According to the different electron acceptors, different PAOs ofPO, PN, PNn, PON, PONnwere selected and enriched in the two SBR systems; includingthat PONand PONnwere the biological phosphorus removal main body in A/O-SBRsystem, PN, PNnwere the biological phosphorus removal main part in A/A-SBRsystem, higher facultative PAOs ratio and more abundant PAOs species, moreconducive to phosphorus removal system stability and higher phosphorus removalcapacity. The results showed that there was significant difference of theory sludgeyield at different condition for electron accepter of O2and NO3-. This was becausedifferent electrons needed different microbial population, which had different cellyield. But there was no significant difference for observed sludge yield at both anoxicand aerobic conditions, because the endogenesis respiration of aerobic sludge wasstronger consequently more sludge being attenuated.