16S rRNA metagenomic analysis of integrated ion exchange partial nitrification-anammox (IX-PN/A) reactor under varying recirculation rates and low-temperature conditions

This study investigates the microbial community structure and dynamics in an integrated ion exchange partial nitrification-anammox (IX_PN/A) wastewater treatment reactor under varying operational conditions. The IX_PN/A process combines ion exchange technology with biological nitrogen removal, offering a promising approach for treating low-strength wastewater at low temperatures. We examined how different recirculation rates (40 ml per min and 10 ml per min) and temperatures (15, 20, and 25 degrees Celsius) affect the microbial community composition and spatial distribution within the reactor.Samples were collected from multiple locations within the reactor, including different carrier materials (zeolite and lava rock) and suspended sludge fractions from both upper and lower zones of the reactor. High-throughput 16S rRNA gene amplicon sequencing was performed to characterize the bacterial communities associated with different operational conditions.The findings from this study will provide insights into the microbial ecology of advanced biological nitrogen removal systems and inform the optimization of IX_PN/A reactor design and operation for enhanced nitrogen removal efficiency under low-temperature conditions.