Biography
Biography: Oluyemi O. Awolusi
Abstract
Nitrification is a critical step that depends on the physiology and function of nitrifying microbial diversity in the activated sludge treatment systems. Optimum and efficient nitrification hinges on a better understanding of the structure and dynamics of the nitrifying community structure within the wastewater treatment systems. Different molecular techniques have been successfully employed for characterizing the microbial structure of activated sludge but not without their inherent shortcoming of underestimation. In this study high throughput pyrosequencing was employed in profiling the ammonia oxidizing bacteria (AOB) in activated sludge treating municipal waste. PCR based phylogenetic analysis was also carried out. The average operating and environmental parameters as well as nitrification efficiency of the plant was monitored during the study. During the investigation the average temperature was 23±1.5oC. The dissolved oxygen level in the plant was constantly lower than the optimum (between 0.24 and 1.267 mg/l) during this study. The plant was treating wastewater with influent ammonia concentration of 31.69 and 24.47 mg/l. The influent flow rates (ML/Day) was 96.81 during period. The dominant nitrifiers include: Nitrosomonas spp. Nitrobacter spp. and Nitrospira spp. The diversity of AOB the nitrifiers involved with first rate limiting step of ammonia removal had correlation with nitrification efficiency and temperature. Pyrosequencing revealed more details in terms AOB diversity compared to the usual PCR-cloning, as there was species that could only be revealed by pyrosequencing. This result demonstrated the underestimation of the AOB diversity based on the molecular techniques that have been relied upon. The findings of the current study have set the foundation for future research on using pyrosequencing to understand the diversity and role of uncultured AOB in wastewater treatment