菌-藻共生好氧颗粒污泥的稳定性机理

在非曝气条件下接种好氧颗粒污泥(AGS)和绿藻藻种,经过18d的培养,成功构建了菌-藻共生好氧颗粒污泥系统(ABGS).研究表明,在非曝气条件下,与传统的AGS相比,ABGS具有更高的生物活性、除污染效能和机械强度,说明ABGS的稳定性更优.对ABGS的稳定性机理进行分析,发现在颗粒化过程中,胞外聚合物(EPS)特别是紧密结合层EPS(TB-EPS)中蛋白质(PN)含量明显增加,实验末期其含量增加至114.4mg/g MLSS,约为AGS的2.8倍.采用三维荧光光谱进一步分析EPS的组分,结果表明TB-EPS中氨基酸、色氨酸、芳香族蛋白质、络氨酸和色氨酸类物质是维持颗粒结构稳定性的重要原因.在微生物群落结构方面, ABGS的物种多样性和群落丰富度更高,原核生物绿弯菌门(Chloroflexi)和浮霉菌门(Planctomycetes)、真核生物绿藻门(Chlorophyta)的富集有利于加强系统的稳定性.

The stability mechanism of algal-bacterial granular sludge

A stable algal-bacterial granular sludge (ABGS) system was established rapidly within 18 days by inoculating with aerobic granules and targeted algae (Chlorella and Scenedesmus) under non-aeration conditions. The results indicated that ABGS had higher biological activity, better nutrients removal performance, and higher mechanical strength than the conventional AGS, indicating the superior stability of ABGS. Moreover, the content of protein (PN) in extracellular polymeric substances (EPS), especially tightly bound layer EPS (TB-EPS), was found increasing significantly during the granulation. Specifically, the PN content of 114.4mg/g MLSS at the end of the operation was about 2.8 times higher than that of AGS. Further analysis of EPS components by three-dimensional fluorescence spectroscopy showed that amino acids, tryptophan, aromatic proteins, complex amino acids and tryptophan-like substances in TB-EPS were conducive to maintain the structural stability of granular sludge. In terms of microbial community structure, the ABGS had a higher microbial diversity and community richness than AGS. The enrichment of the prokaryotic Chloroflexi and Planctomycetes, and the eukaryotic Chlorophyta was beneficial to enhance the stability of the system.