| Denitrifying phosphorus removal process is known as an enhanced biological phosphorus and nitrogen removal technology which has a good prospect because of the advantages such as saving energy of aeration and less sludge production. It could solve the problems of sludge and carbon source occurred in the cultural process efficiently. The type of carbon source is one of the critical factors on the denitrifying phosphorus removal technology.This study focused on the influence of intracellular polymers with different composition and qualities on denitrification and denitrifying phosphorus removal by3kinds of carbon sources, sodium acetate, ethanol and glucose. Firstly, the editor used3anaerobic-aerobic-anoxic operated sequencing batch reactors (SBR) fed up with unique carbon source, sodium acetate (RAc), ethanol (RE) and glucose (RG), respectively, then has a macro exploration by three aspects:the removal rate of CODCr, PO43--P and the efficiency of denitrifying phosphorus removal. Secondly, the editor utilized2anaerobic-settling/changing-anoxic-aerobic operated SBRs fed with sodium acetate (R1,R2) to investigate the effect of intracellular polymers on denitrification and denitrifying phosphorus removal respectively by controlling the adding time of KH2PO4. Finally, the researcher utilized3SBRs which had the same operation, conditions and measurements as the2SBRs aforementioned. Fed the3SBRs with unique carbon source sodium acetate (Ac-SBR), ethanol (E-SBR) and glucose (G-SBR) respectively and investigated the roles of different intracellular polymers synthetized by different carbon sources in denitrification and denitrifying phosphorus removal process.The results were as follows:1. The removal rates of CODCr, PO43--P, and NO3--N were all the best in Rac, and the removal rate of PO43--P in RG the worst.2. The test preliminary found and proved that denitrification process could be achieved by denitrifying bacteria using Poly-β-Hydroxyalkanoate(PHA) as an internal carbon source with the low concentrations of PO43--P(<2.6mg·L-1) and external carbon source, it also accompanied with the resynthesis of Glycogen.3. Besides the collaboration between denitrifying bacteria and Denitrifying Polyphosphate Accumulating Organisms (DPAOs), there was a competition on striving for intracellular polymers as internal carbon source to gain the energy to accomplish their functions. In the Ⅱ part of anoxic phase in R2, Glycogen degraded as assistant internal carbon source when the degradation rate of PHA was low. The results also released that R2was better for the metabolism of Glycogen Accumulating Organisms (GAOs) than R1because of the domestication of denitrification process. 4. The efficiency of PO43--P releasing by Polyphosphate Accumulating Organisms (PAOs) under anaerobic condition in Ac-SBR was the best among the3systems, and both worse in E-SBR and G-SBR. In the part A of anoxic phrase without PO43--P, the variation of parameters displayed that Poly-β-Hydroxybutyrate (PHB) was the dominant organic compound in denitrification process, and the consumption of Poly-β-Hydroxyvalerate (PHV) was advantageous to Glycogen resynthesis.5. Different kinds of intracellular polymers in different carbon source systems had different roles. In Ac-SBR, both PHA and Glycogen could be utilized as the internal carbon sources to drive denitrification and denitrifying phosphorus removal processes, PHB became the dominate one and first degraded. PHA in E-SBR degraded as an internal carbon source for both denitrifying phosphorus removal and Glycogen resynthesis. In G-SBR, the resynthesis and the activeness of Glycogen in were more evident than other systems, but the rate of denitrification and denitrifying phosphorus removal were the lowest among the3SBRs. Therefore, G-SBR system was better for the metabolism of GAOs which could synthetic Glycogen than PAOs or DPAOs; there would be a competition between GAOs and PAOs which might be negative effects on denitrifying phosphorus removal process. |
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