Wang Xiao-Meng, Wang Xin, Yang Ming-Hui, Zhang Shu-Juan
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China.
Huan Jing Ke Xue. 2018 May 8;39(5):2274-2282. doi: 10.13227/j.hjkx.201710205.
The sludge conditioning performance of inorganic Al, Fe, and Ti coagulants were systematically compared in terms of specific resistance to filtration (SRF), the content of protein and polysaccharide in extracellular polymeric substances (EPS), the change in three-dimensional excitation emission matrix fluorescence (3D-EEM), the molecular weight of organic matter in EPS, and the floc size and surface morphology. The sludge conditioning ability and the mechanism were systematically analyzed. The results showed that the sludge conditioning ability of the three inorganic coagulants was in the order of polyaluminum chloride (PAC) > titanium xerogel coagulant (TXC) > polymeric ferric sulfate (PFS). After conditioning, the contents of protein and polysaccharide in the EPS were greatly reduced, especially in the loosely bound EPS (LB-EPS). The combined capacity for coagulation between TXC/PFS and organic matter was stronger than that of PAC. The content of polysaccharide in LB-EPS was the key factor affecting the sludge dewatering performance but not the coagulated floc size. The surface charge and the chelating ability with organic matter co-determined the sludge dewatering ability. The organic cationic polymer, polyacrylamide (PAM), made the sludge aggregate via charge neutralization. However, the use of PAM alone was not a good choice owing to the low dewatering ability and the loose sludge structure. The results here are helpful for the selection of suitable coagulants for sludge conditioning.
从过滤比阻（SRF）、胞外聚合物（EPS）中蛋白质和多糖的含量、三维激发发射矩阵荧光（3D-EEM）的变化、EPS中有机物的分子量以及絮体大小和表面形态等方面，系统地比较了无机铝、铁和钛混凝剂的污泥调理性能。系统分析了污泥调理能力及其作用机制。结果表明，三种无机混凝剂的污泥调理能力顺序为：聚合氯化铝（PAC）＞钛凝胶混凝剂（TXC）＞聚合硫酸铁（PFS）。调理后，EPS中蛋白质和多糖的含量大幅降低，尤其是在松散结合的EPS（LB-EPS）中。TXC/PFS与有机物之间的混凝结合能力强于PAC。LB-EPS中多糖的含量是影响污泥脱水性能的关键因素，而不是混凝后的絮体大小。表面电荷和与有机物的螯合能力共同决定了污泥的脱水能力。有机阳离子聚合物聚丙烯酰胺（PAM）通过电荷中和使污泥聚集。然而，单独使用PAM不是一个好选择，因为其脱水能力低且污泥结构松散。本文结果有助于选择合适的混凝剂用于污泥调理。
