Characteristics of oxygen mass transfer and its impact on pollutant removal performance and microbial community structure in an aerobic fluidized bed biofilm reactor for treatment of municipal wastewater

A laboratory-scale aerobic fluidized bed biofilm reactor (AFBBR) was established to evaluate the oxygen mass transfer (OMT) process and its impact on municipal wastewater treatment performance. Aeration rates had different effects on the OMT of the wastewater and biofilm. In the wastewater, oxygenation performance, oxygen uptake rate (OUR), and volumetric OMT coefficient (kLa) improved under high aeration rates. However, within the biofilm, the OMT process under the aeration rate of 0.096 L/(min·L) were higher than under other conditions [0.064 L/(min·L) and 0.128 L/(min·L)]. The denitrifying bacteria (DNB) abundance under the aeration rate of 0.096 L/(min·L) were improved so that total nitrogen (TN, 66.98 ± 4.23%) and ammonia nitrogen (NH4+-N, 74.70 ± 2.30%) removal were higher than those under other aeration conditions. These results showed that suitable aeration could improve wastewater treatment efficiency through changing the OMT process and microbial community structure.