The difficulties in dewatering waste-activated sludge (WAS) using mechanical devices have caused great problems in sludge transportation and disposal. Herein, coagulation and flocculation are combined with the use of a magnetic field as a clean and low-energy physical treatment method to enhance the dewaterability of municipal and citric acid–processing WAS. It is shown that the use of the magnetic field had a significant effect on the capillary suction time (CST) of municipal WAS but not on the specific resistance filtration (SRF) and CST of the citric acid WAS. The differences in the magnetic field effects were due to differences in the sludge properties. For municipal WAS, the particle size decreased, the zeta potential remained unchanged, and the viscosity decreased, whereas in the citric acid WAS, the particle size increased, the absolute value of the zeta potential decreased, and the viscosity increased. In addition, these effects were also confirmed with studies of the water state and micro-morphology analyses. It is shown that the acidification of the municipal WAS and coagulation of citric acid WAS were likely the reasons for the enhancement of their dewaterability, respectively. This study confirmed that the use of a magnetic field combined with coagulation/flocculation may serve as an effective sludge conditioning method; however, the treatment conditions may vary with the sludge type.

使用机械装置对废物活性污泥（WAS）进行脱水的困难给污泥的运输和处置带来了很大的问题。在此，混凝和絮凝结合使用磁场作为清洁和低能量的物理处理方法，以提高市政和柠檬酸处理 WAS 的脱水能力。结果表明，磁场的使用对市政WAS的毛细抽吸时间（CST）有显着影响，但对柠檬酸WAS的比阻过滤（SRF）和CST没有影响。磁场效应的差异是由于污泥性质的差异。对于市政WAS，粒径减小，zeta电位保持不变，粘度降低，而在柠檬酸WAS中，粒径增加，zeta电位的绝对值降低，粘度增加。此外，这些影响也通过水状态和微形态分析的研究得到证实。结果表明，市政WAS的酸化和柠檬酸WAS的混凝可能分别是其脱水能力增强的原因。该研究证实，使用磁场结合混凝/絮凝可以作为一种有效的污泥调理方法；但是，处理条件可能因污泥类型而异。结果表明，市政WAS的酸化和柠檬酸WAS的混凝可能分别是其脱水能力增强的原因。该研究证实，使用磁场结合混凝/絮凝可以作为一种有效的污泥调理方法；但是，处理条件可能因污泥类型而异。结果表明，市政WAS的酸化和柠檬酸WAS的混凝可能分别是其脱水能力增强的原因。该研究证实，使用磁场结合混凝/絮凝可以作为一种有效的污泥调理方法；但是，处理条件可能因污泥类型而异。