| Summary: | 碩士 === 國立雲林科技大學 === 環境與安全工程系碩士班 === 92 === The performance of enhanced biological phosphorus removal (EBPR) process was often destroyed under some non-identified condition. The appearance of glycogen accumulating organism (GAO) was opinioned to be one of the main reasons. Brdjanovic(1999) established a simple experimental method to caculate the ratio of phosphate accumulating organism (PAO) and glycogen accumulating organism (GAO) in ehanced biological phosphate removal (EBPR) process;however, this method will not be applicable when the ratio of GAOs to PAOs is too low (say<10%) or too high (>90%). Thus, this study proposed a new method, i.e SBT method, to compute the GAOs/PAOs ratio. The method was designed in which PAO-enriched sludge or GAO-enriched sludge was exposed to anaerobic/centrifuge/aerobic/anaerobic batch experiment. The GAOs/PAOs ratio can therefore be obtained from the anaerobic substrate uptake rate of PAO and GAO.
Besides, this study try to revise the method proposed by Hu(2003) in which PAO was characterized by using three different electron acceptors. Finally, batch tests using nitrite as electron acceptor of PAO-enriched sludge and GAO-enriched sludge were performed to find out the kinetic behavior of PAO and GAO. Experimental results showed that the new method established by this study doesn’t have any restriction in PAO/GAO ratio and have wider application range than Brdjanovic method. In addition, the ratio of PAO/GAO caculated by the modified-Brdjanovic method is nearly the same with SBT method. It means that SBT method and modified-Brdjanovic method can be displaced to each other. The PAO:GAO ratio of PAO-enriched sludge and GAO-enriched sludge were caculated by the proposed SBT method to be 83%：17% and 26%：74%, respectively.
Additionally, this study try to use Fluorescence in situ Hybridization (FISH) to verified the ratio of PAO-enriched sludge and GAO-enriched sludge caculated by SBT method. It showed that GAO actually existed in the PAO-enriched sludge and PAO appears in GAO-enriched sludge after Neisser staining and FISH experiment. In addition, the PAO/GAO ratio caculated by FISH method is close to SBT method, although have a little difference.
This study combine Hu(2003) method and Wachmeister(1997) method for classifying the population of PAO by using oxygen, nitrate and nitrite to be electron acceptor. Besides, due to GAO doesn’t perform phosphate metabolism , this study try to establish a new method for characterizing GAO by using different electron acceptor. The batch experiment procedure is anaerobic/centrifuge(no phosphate resupply)/anoxic(aerobic)/anaerobic and specific substrate uptake rate were caculated by second anaerobic phase. The experimental results was listed as following (GAOO：GAO which can only use oxygen as electron acceptor、GAOON：GAO which can only use oxygen and nitrate as electron acceptor、GAOONn：GAO which can use oxygen、nitrate and nitrite as electron acceptor、PAOO：PAO which can only use oxygen as electron acceptor、PAOON：PAO which can only use oxygen and nitrate as electron acceptor、PAOONn：PAO which can use oxygen、nitrate and nitrite as electron acceptor)：
I. In the PAO-enriched sludge：GAOO = 8.3%、GAOON = 2.6%、GAOONn = 6.2% 、PAOO = 48%、PAOON = 12%、PAOONn = 24%.
II. In the GAO-enriched sludge：GAOO = 22.9%、GAOON = 12%、GAOONn = 39%、PAOO = 11.4%、PAOON = 2.4%、PAOONn = 12.4%.
Finally, the batch experiment showed that the phosphate uptake of PAO was inhibited when nitrite concentration exceeded 15mg/L. The inhibition and kinetic constants were analysed to be KI = 6.9mgNO2-/L、qmax = 27.7mgP/gMLSS/h and Ks = 22.14mgNO2-/L. Besides, using the kinetic behavior of PAO-enriched sludge to represent PAO may not be applicable. The kinetic behavior of GAO clearly followed monod equation . The kinetic constants of GAO using nitrite as electron acceptor is caculated to be qmax = 1.35 mgN/gMLSS/h and Ks = 4.75 mgNO2-/L.
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