|
|
|
| Effect of sludge loading rate on the growth and distribution of sulfadiazine-resistant bacteria |
|
|
|
|
Abstract 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.
|
|
Received: 21 November 2013
|
|
|
|
|
|
|
