提高有机负荷对好氧颗粒污泥形成与稳定过程的影响

Effect of Increasing Organic Loading Rate on the Formation and Stabilization Process of Aerobic Granular Sludge

本研究在柱形SBR反应器中接种市政污水厂活性污泥,以乙酸钠为碳源,考察了逐步提高进水有机负荷(OLR)对好氧颗粒污泥(AGS)形成的影响,并分析了污泥外观形态、微生物活性与胞外聚合物(EPS)组成的演化规律.结果表明,当进水OLR在3.20~4.84 kg·(m3·d)-1时,污泥粒径的增长速率最快.更高的OLR将导致絮状污泥的大量出现,需辅以应急性排泥,才能保持AGS在反应器中的主导地位.成熟AGS的污泥浓度(MLSS)、污泥体积指数(SVI30)、平均粒径、沉降速率和比耗氧速率(SOUR)分别达到23.9 g·L-1、20 m L·g-1、1.4 mm、102 m·h-1和50.2 mg·(g·h)-1.污泥颗粒化过程不仅使污泥形态发生了根本变化,也显著增强了微生物活性.在此期间,胞外聚合物中PN、PS含量的变化对生物量累积、颗粒生长表现出良好的响应关系.充分发挥EPS组分的指示功能,将有助于优化现有AGS的培养方法.

In order to evaluate the effect of organic loading rate( OLR) on the formation of aerobic granular sludge( AGS),a lab-scale cylindrical SBR reactor( sodium acetate as carbon source) was constructed and inoculated with collected sewage sludge. The evolution of morphology,microbial activity and extracellular polymeric substances( EPS) characteristics of sludge samples in the reactor were recorded and analyzed. The results showed that AGS has the highest growth rate under the condition of 3. 20-4. 84 kg·( m3·d)- 1OLR,and a selective discharging strategy of the floccular sludge was suggested to maintain the predominance of AGS in reactor. The accumulated sludge concentration,SVI30,mean granule size,settling velocity and SOUR value of the AGS in steady-state operated SBR was 23. 9 g·L- 1,20 m L·g- 1,1. 4 mm,102 m·h- 1and 50. 2 mg·( g·h)- 1,respectively. The granulation process not only obviously changed the sludge appearance,but also significantly improved the microbial activity. Meanwhile,linear correlation was observed between the variation of protein/polysaccharide concentration and the granule size of AGS. Thus,variation of protein /polysaccharide concentration of the EPS could be applied as an indicator for optimization of the cultivation method of AGS.