环丙沙星对膜生物反应器运行效能的影响及其去除特性

采用膜生物反应器(membrane bioreactor,MBR)处理含环丙沙星(ciprofloxacin,CIP)的模拟废水,考察了不同CIP投加浓度(0、5、10 mg·L~(-1))下的污染物去除效果和微生物群落的变化.结果表明,随着CIP投加浓度从0 mg·L~(-1)增加至5 mg·L~(-1)再增加至10 mg·L~(-1),反应器中污泥浓度呈现先减少后波动平衡的趋势;COD和TOC平均去除率分别从98.40%和97.80%下降至84.20%和94.10%,表明CIP对有机物去除有所影响但影响程度不大;氨氮去除效率受CIP投加浓度的影响较大,随着CIP投加浓度从0 mg·L~(-1)增加至5 mg·L~(-1)再增加至10 mg·L~(-1),氨氮去除效率从96.91%降低至84.14%再降低至77.80%,亚硝化单胞菌属(Nitrosomonas)、产碱菌属(Alcaligenes)、硝化螺旋菌属(Nitrospira)和硝化杆菌属(Nitrobacter)的活性明显下降;而CIP去除率总体呈现先增后减的趋势.物料衡算分析表明,MBR中CIP的去除主要是通过生物降解和污泥吸附,在CIP投加浓度为5 mg·L~(-1)时分别去除了30.13%和0.25%的CIP,在CIP投加浓度为10 mg·L~(-1)时分别去除了7.55%和1.81%的CIP.

Removal and Influence of Ciprofloxacin in a Membrane Bioreactor

A membrane bioreactor (MBR) was used to treat ciprofloxacin (CIP)-contaminated artificial wastewater. The pollutant removal performance and the microbial community structure of the MBR were studied at three different CIP dosages (0 mg·L^-1, 5 mg·L^-1, and 10 mg·L^-1). The results showed that the sludge concentration in the reactor decreased and then levelled off as the dosage of CIP was increased from 0 mg·L^-1 to 5 mg·L^-1 and further to 10 mg·L^-1. The mean removal of TOC and COD decreased from 98.40% and 97.80% to 84.20% and 94.10%, respectively, indicating that the CIP negatively influenced the organic removal but the effect was minor. In contrast, the ammonium removal was greatly influenced by the dosage of CIP. When the CIP dosage increased from 0 mg·L^-1 to 5 mg·L^-1 and further to 10 mg·L^-1, the ammonium removal efficiency decreased from 96.91% to 84.14% and then to 77.80%, and the activity of Nitrosomonas, Alcaligenes, Nitrospira, and Nitrobacter were greatly inhibited. The CIP removal initially increased and then decreased. The mass balance revealed that the removal of CIP in the MBR was principally attributed to biodegradation and sludge adsorption, which accounted for 30.13% and 0.25%, respectively, at a CIP dosage of 5 mg·L^-1 and 7.55% and 1.81% at a CIP dosage of 10 mg·L^-1.