| dc.description.abstract | The microorganisms are very important in the biological nutrient removal (BNR) process due to the directly degradation of nutrient from wastewater. Different microorganism has its own metabolism, i.e., to degrade different substrate. Thus, to understand the microbial diversity of a BNR process is necessary. Since the traditional microorganism analytical method has lots of bias, this dissertation utilizes the 16S rDNA molecular biotechnology to investigate the microbial diversity of several wastewater treatment processes, include a municipal wastewater treatment plant, an A2O pilot plant and a TNCU-I pilot plant.
The result showed that the Proteobacteria was the predominant bacteria in all samples, that is 47.4%, and 63.3% in A2O and TNCU-I process, respectively. The beta-subclass of Proteobacteria was the most predominant one in A2O and TNCU-I processes, but not in municipal wastewater treatment plant. The Gamma-subclass was predominant in all samples in a range of 14.6% to 21.6 %. No alpha-subclass was identified in all samples. The Delta-subclass was only observed in TNCU-I activated sludge. The epsilon-subclass was minor in the BNR process but was predominant in municipal wastewater treatment plant that is about 23.4 %. Furthermore, all the BNR samples could observe the genus Nitrospira and genus Nitrosospira. The genus Nitrosomonas was also observed in RBC biofilm.
As the nitrogen removal performance of A2O and TNCU-I was 63.2% and 82.9 % respectively, a certain bacteria were identified as nitrogen removal bacteria in both two processes. Additionally, lots of bacteria were identified as phosphate removal bacteria, corresponding to the phosphate removal efficiency of 100% in both processes.The result showed that the nitrifier, denitrifier and phosphate removal bacteria could be observed in TNCU-I process, corresponding to the excellent nitrogen and phosphate removal efficiencies.
Among the phosphate removal bacteria in TNCU-I process, 13.2% of total bacteria were identified as DNPAO-like bacteria, which could uptake phosphate under anoxic condition by using nitrate as electron acceptor. | en_US |