METABOLIC SHIFT AND NICHE DIFFERENTIATION DURING DENITRIFYING PHOSPHORUS REMOVAL IN A TROPICAL CLIMATE

This work aims to increase current knowledge of microbial communities and their metabolic underpinnings in EBPR processes under tropical conditions. Aerobic granulation and alternating carbon sources were used to obtain Accumulibacter enrichment at 30&176C. It was surmised that involvement of partial TCA-glycolysis cycle or complete glycolytic pathway in Accumulibacter affects phosphorus removal efficiency. Accumulibacter has also been shown to utilize nitrate or nitrite as terminal electron acceptor under anoxic conditions. Differences in microbial community structure were observed between long-term nitrite- and nitrate-mediated denitrifying phosphorus removal processes. Nitrite as terminal electron acceptors inhibited growth of GAOs. Finally, the denitrification abilities and N2O reduction capability of Accumulibacter was characterized and contrasted with Competibacter and Defluviicoccus. A clear preference for nitrite utilization was observed for Accumulibacter while nitrate utilization was prevalent in Competibacter and Defluviicoccus. The results obtained in this thesis corroborate that for successful implementation of the EBPR process in tropical climates.

Author dc:creator

• SAMARPITA ROY

• Aerobic granules, Enhanced biological phosphorus removal (EBPR), denitriifcation, nitrous oxide, glycogen accumulating organisms (GAOs),Accumulibacter