Pollution characteristics and risk assessment of antibiotics in sludge from pharmaceutical wastewater treatment plants: the influence of production load
PENG Xin-yi1, LI Yu-hua1, YANG Xiao1, RU Xuan1, CHEN Rui-hong1, QIN Yong-li1, HUANG Xin-hui1, XU Dan-ning1, SHU Xiao-hua2, ZHANG Qian1
1. School of Life and Environmental Science, Guilin University of Electronic Technology, Guilin 541004, China; 2. College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541006, China
Abstract：Sludge from pharmaceutical wastewater treatment plants serves as a major reservoir for antibiotics. This study aimed to investigate the residual characteristics of antibiotics in sludge from different stages of wastewater treatment under varying production loads, and to assess the potential ecological risks of physicochemical and biochemical dewatered sludge using the Risk Entropy(RQ) method. The results indicated that 11 types of antibiotics were detected in the sludge under both high and low production loads, with total detected concentrations of 401.72μg/kg and 55.02μg/kg, respectively, showing significant differences in concentrations among different antibiotics. The production load had a notable impact on the wastewater treatment process. Principal component analysis (PCA) delineated robust disparities in antibiotic concentrations and water quality parameters among various treatment stages, with these differences being more pronounced under high production loads than under low production loads. Furthermore, redundancy analysis (RDA) underscored the substantial influence of distinct wastewater quality parameters on the removal efficacy of antibiotics. Residual levels of antibiotics from pharmaceutical processes remained relatively high in both physicochemical and biochemical dewatered sludge, with elevated concentrations of 9.39μg/g in low production load physicochemical sludge and 12.91μg/g in high production load biochemically dewatered sludge. Erythromycin, roxithromycin, and sulfamethoxazole in sludge-amended soil posed a high risk (RQ>10) to aquatic organisms in the receiving environment, with sulfadimethoxine exhibiting the most pronounced environmental risk (RQ>295.04). Macrolides and sulfonamide were identified as the primary risk factors in pharmaceutical plants, and it is recommended that these be prioritized for pollution control. The ecological risk posed by mixed antibiotics was significantly higher than that of individual antibiotics. Therefore, careful consideration of the final disposal of both physicochemical and biochemical sludge is crucial.
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