Effect of Biofilm Architecture. Effect of Biofilm Architecture on the Activity and Community Composition of Phosphorus Accumulating Bacteria in a Moving Bed Biofilm Reactor

Biofilm-based phosphorus recovery can improve the robustness of conventional removal of phosphorus from wastewater, but the process is poorly investigated. This study examined the effect of biofilm thickness on the activity and microbial diversity of phosphorus-accumulating bacteria. Biofilms of 30 to 1000 µm were grown on 5 different carriers in a moving bed biofilm reactor. Measurements on each type of carrier showed that biomass-specific phosphorus release and uptake rates increased as a function of biofilm thickness for biofilms thinner than about 110 µm but were lower for thicker biofilms of about 550-1000µm. On the other hand, anaerobic acetate consumption rates were rather similar for the thinner but decreased for the thicker biofilms. The reduced phosphorus uptake and release rates in the thickest biofilms can result from substrate mass transfer limitations whereas the low activity in the thinnest biofilms can be related to a too high turnover rate in the biofilm due to heterotrophic growth.

基于生物膜（biofilm）的磷回收工艺可提升传统污水除磷过程的鲁棒性，但该工艺的相关研究仍较为匮乏。本研究探究了生物膜厚度对聚磷菌活性与微生物多样性的影响。研究在移动床生物膜反应器（moving bed biofilm reactor）内的5种不同载体上，培养了厚度介于30~1000 µm的生物膜。对每种载体的检测结果显示，当生物膜厚度小于约110 µm时，单位生物质的磷释放与摄取速率随生物膜厚度增加而升高；但当生物膜厚度处于550~1000 µm的较厚区间时，该速率则显著降低。另一方面，较薄生物膜的厌氧乙酸盐消耗速率较为接近，而较厚生物膜的该速率则出现明显下降。最厚生物膜中磷摄取与释放速率的降低，可能源于底物传质限制；而最薄生物膜的活性偏低，则可能与异养生长导致的生物膜内周转速率过高有关。