连续进水对好氧颗粒污泥稳定维持的影响

The effect of continuous feeding on the stability of aerobic granular sludge

为了考察连续进水对好氧颗粒污泥稳定维持的影响,在SBR反应器中接种成熟的好氧颗粒污泥,采用连续进水、间歇出水的方式运行.在反应器运行过程中,部分好氧颗粒污泥解体,完整存在的好氧颗粒污泥表面附着生长树枝状污泥和少量丝状菌.SVI在最初的13d内逐步上升,随后趋于稳定.同时,考察了好氧颗粒污泥在连续进水运行过程中EPS含量的变化以及EPS的空间分布变化:胞外多糖的含量在运行过程中呈下降趋势;胞外蛋白的含量整体呈先上升后下降的趋势;反应器运行15d后,胞外蛋白和胞外多糖的含量趋于稳定.连续进水运行30d后,EPS空间分布最大变化是β-D吡喃葡萄糖,它大量聚集在颗粒的表层及颗粒中伸出的树枝状污泥及丝状菌的表层.本研究表明,连续进水的运行方式不利于好氧颗粒污泥的稳定维持,底物浓度梯度为好氧颗粒污泥稳定维持的重要因素之一;EPS的分泌量以及空间分布对好氧颗粒污泥的形成及其稳定维持起着至关重要的作用.

The effect of continuous feeding on the stability of aerobic granular sludge （AGS） was investigated. A lab-scale sequencing batch reactor （SBR） seeded with mature AGS was operated for 30 days under a continuous feeding pattern. Under these conditions,part of the AGS disintegrated,and much tree-like sludge and some filamentous bacteria grew on the surface of the remaining AGS. During the first 13 days,the sludge volume index （SVI） increases rapidly,and then becomes stable. Quantitative investigation of the extracellular polymeric substances （EPS） indicates that extracellular polysaccharides decrease while extracellular proteins first increase and then decrease. After about 15 days,the content of EPS becomes steady. EPS staining shows that the proteins contribute to the formation of the core of the AGS,whereas the α-glucopyranosyl polysaccharides and β-D-glucopyranose polysaccharides accumulate in the outer layers of the AGS. After 30 days,the positions of proteins and α-glucopyranosyl polysaccharides change slightly,but the number of β-D-glucopyranose polysaccharides accumulated at the outer layer increases greatly. EPS staining also indicates that the stability of AGS is dependent on the protein core,and β-D-glucopyranose polysaccharides could be used to evaluate whether the AGS is stable or not. The results of this study show that continuous feeding is not favorable for the stability of AGS because of the low substrate gradient.