| Circular plug-flow reactor had already been approved as invention patent(ZL200710092501.7), and the flow pattern of circular plug-flow reactor was analyzed in thisthesis by residence time distribution function (RTD) method with potassium chloride(KCL) and computational fluid dynamics (CFD) method with the software of FLUENTsimultaneously. Molecular biology technique of PCR-TGGE was used to researchmicrobial community structure. Then the activity of microorganism and decaycharacteristic of activated sludge in circular plug-flow system had been researched bycombing LIVE/DEAD Baclight technique with TTC-dehydrogenase activitydetermination method. Thirdly, according to the long time experimental data foroperation of circular plug-flow system, the pollution removal effects, activated sludgecharacteristic and operation condition under low temperature were investigated. Finally,the denitrifying phosphate-removal bacterias were screened from circular plug-flowreactor and the characteristics of these denitrifying phosphate-removal effects were alsostudied in this thesis.This research was mainly carried out in the following several aspects:①The results of stable operation in long experiment period showed that: theaverage removal rates of CODCr, TN, TP and NH4+-N were91.38%,75.77%,82.84%and81.23%, respectively. Amost all of parameters during experiment period can meetthe B standard of first grade of China Discharge standard of pollutants for municipalwastewater treatment plant (GB18918-2002).②The RTD tests and COD remove experiment showed that: the removalefficiency of PFR (The number of series is6.92) was3.18times of that of CSTR (Thenumber of series is1.20). The flow pattern simulation of circular plug-flow system byFLUENT, the CFD software, had the similar result of traditional RTD method, whichshowed the circular plug-flow reactor had a higher proportion of plug flow pattern, thiswas one of the reasons of the good removal efficiency of the circular plug-flow system.③According to TGGE result, the circular plug-flow system had rich biofacies andmicroorganism not only in July (average water temperature is about26.5℃) but also inDecember (average water temperature is about10.8℃), this was the another reason ofthe good removal efficiency of the circular plug-flow system.④According to the bacterial decay characteristics experimental, results revealed that77.21%of cell decay in circular plug-flow system was caused by activity decreaseand22.79%was caused by cell death.⑤The average sludge yield of circular plug-flow system was0.26gMLSS/gCOD,it’s lower than conventional activated sludge processes.⑥Four denitrifying phosphate-removal bacteria strians were screened fromcircular plug-flow reactor and be identified as Alcaligenes sp., Alcaligenes faecalis,Bacillus cereus and Pseudomonas Medocina according to their morphological,physiological-biochemical reactions and16S rDNA sequence homology comparison.And in the denitrifying phosphate-removal experiment, the removing rate of phosphorusand nitrogen were93.00%,71.14%,74.18%,75.72%and94.39%,96.84%,86.77%,86.57%, Poly-β-hydroxybutyric (PHB) was the key in whole denitrifying phosphate-removal process. |
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