Institute of Plant Nutrition and Resources, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097, China.
Institute of Plant Nutrition and Resources, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097, China.
Colloids Surf B Biointerfaces. 2019 Apr 1;176:202-211. doi: 10.1016/j.colsurfb.2019.01.001. Epub 2019 Jan 2.
In order to evaluate the effects of hydraulic shearing action on activated sludge floc aggregation, floc aggregation, breakage and re-growth performances under different shear strengths were systematically examined. Performances were evaluated by measuring the floc size variations using a laser particle size analyser on-line monitoring technique. The flocs after breakage were characterised by investigating the composition of extracellular polymer substances (EPS), floc size, substances released due to surface erosion and chemical structures using Fourier transform infrared spectroscopy (FTIR) to clarify the breakage model and re-growth mechanism. The results showed that activated sludge flocs broken at a hydraulic shear strength GT value (the product of the velocity gradient and time) of 56,280 exhibited enhanced re-growth performance compared with the control. The substances released from sludge increased with shear strength, indicating that the floc breakage mode gradually transitioned from fragmentation to surface erosion. FTIR revealed that, after breakage, the spectrum of loosely bound EPS in sludge tended to be similar to that of tightly bound EPS. The results suggest that the breakage of activated sludge flocs under moderate hydraulic shear strength can fragment flocs into smaller particles without surface erosion and promote the exposure of inner tightly bound EPS, thereby improving re-growth performance.
为了评估水力剪切作用对活性污泥絮体聚集的影响，系统研究了不同剪切强度下的絮体聚集、破碎和再生长性能。通过使用激光粒度分析仪在线监测技术测量絮体大小的变化来评估性能。通过使用傅里叶变换红外光谱（FTIR）研究絮体破碎后细胞外聚合物物质（EPS）的组成、絮体大小、由于表面侵蚀和化学结构释放的物质，以阐明破碎模型和再生长机制。结果表明，在水力剪切强度 GT 值（速度梯度和时间的乘积）为 56280 的条件下，活性污泥絮体破碎后表现出增强的再生长性能，与对照组相比。随着剪切强度的增加，从污泥中释放的物质增加，表明絮体破碎模式逐渐从碎裂转变为表面侵蚀。FTIR 表明，破碎后，污泥中松散结合 EPS 的光谱趋于与紧密结合 EPS 的光谱相似。结果表明，在适度的水力剪切强度下，活性污泥絮体的破碎可以将絮体破碎成更小的颗粒，而不会发生表面侵蚀，并促进内部紧密结合 EPS 的暴露，从而提高再生长性能。
