Polyhydroxyalkanoates production by activated sludges from anaerobic/oxic and aerobic dynamic feeding systems

• Main Authors: Hsuan-fang Chang, 張玄芳
• Other Authors: Wei-chin Chang
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/82338699588044931444

博士 === 國立雲林科技大學 === 工程科技研究所博士班 === 100 === This study focuses on investigating various operational parameters of the PHAs producing processes from the anaerobic/oxic (A/O) and aerobic dynamic feeding (ADF) sludges. First, two acetate-fed A/O SBRs were constructed with the same operating conditions except for cultivating at different SRT. The oxic sludge with 5 days SRT showed better PHAs production capability than anaerobic sludge in terms of the kinetics and stoichiometric indexes. In contrast, the anaerobic sludges with 15 days SRT obtained superior PHAs production behavior compared to oxic sludge with the same SRT. These findings demonstrate that the PHAs production performance of the anaerobic and oxic sludges depend upon the operating SRT of the A/O system. In order to increase the HV fraction in industrial P(HB/HV) copolymer, propionate was used as the cultivating substrate for the A/O SBR. Besides, this research also tried to change the operating condition of the reactor from A/O to ADF. Results showed that the operating condition of the reactor shifted from A/O to ADF operation could enhance the PHAs accumulation capability of the propionate-fed SBR. Moreover, the batch production tests also indicated that the ADF sludges with acetate and valerate exhibited better PHAs producing capability compared to the same batch tests from the A/O sludges. Moreover, to obtain the appropriate HV fraction (40-50 mol %) in P(HB/HV), the propionate-fed ADF sludge was harvested to conduct aerobic batch tests under various carbon sources. Experimental results revealed that obtaining appropriate HV fraction required simultaneously two conditions: cultivating a propionate-fed sludge and providing the sludge with mixture of odd- and even-number carbon sources. On the other hand, this study also demonstrate that the PHAs producing capability of the weakly nitrogen-limited sludge from the propionate-fed SBR declined significantly after long-term operation. Batch experiments also revealed that obtaining better PHAs producing performance requires supplying adequate N concentrations (0.7 N mmol/L).