污泥负荷对生物处理系统耐药细菌的影响研究

为了研究污水生物处理工艺中抗药性细菌生长和分布特性及污泥负荷的影响,构建了不同处理负荷的活性污泥工艺,并以磺胺嘧啶抗性异养菌为例,阐述了污泥负荷对活性污泥系统中典型抗药细菌的生长及排放特性的影响.结果表明,污泥负荷增大有利于磺胺嘧啶抗性异养菌的生长繁殖,负荷提高后净比生长速率和细菌产量分别由0.32d-1和2.3×106CFU/d提高至0.33d-1和3.1×106CFU/d,活性污泥、出水和剩余污泥中抗药菌的浓度也均显著提高(P < 0.05),但对抗药细菌的相对丰度无显著改变.低污泥负荷下0.24kg COD/(kg MLSS?d)]抗药细菌主要通过剩余污泥形式排放,排放量比(泥中排放量/水中排放量)为28.4;负荷提高至0.4kg COD/(kg MLSS?d)后,出水抗药细菌排放量显著提高,排放量比为1.1.处理相同水量,高污泥负荷下排放的抗药细菌总量明显降低,提高污泥负荷有利于活性污泥系统抗药性风险的控制.

Effect of sludge loading rate on the growth and distribution of sulfadiazine-resistant bacteria

In order to study the propagation and distribution of antibiotic-resistant bacteria (ARB) in the typical biological treatment process, an activated sludge system with different sludge loading rates was constructed. The effect of sludge loading rate on the growth and release of sulfadiazine-resistant bacteria in the system was then studied. The results indicated that a higher sludge loading rate promoted the growth of sulfadiazine-resistant bacteria. The net specific growth rate and the bacteria production increased from 0.32d-1 and 2.3×106CFU/d to 0.33d-1 and 3.1×106CFU/d, respectively. The concentration of sulfadiazine-resistant bacteria in activated sludge, effluent and biosolids all increased significantly (P < 0.05) with increased sludge loading rate, while the antibiotic resistant characteristic changed slightly. The biosolids was the main released pattern for sulfadiazine-resistant bacteria in the low sludge loading rate 0.24kg COD/(kg MLSS?d)] system, and the released ratio (biosolid/effluent) was 28.4. By comparison, much more bacteria were discharged through effluent in the higher sludge loading rate 0.4kg COD/(kg MLSS?d)] system, with the release ratio (biosolid/effluent) of 1.1. The total discharging load decreased significantly in the system with higher sludge loading rate, which was benefical to the potential ARB risk control.