岸滤系统中磺胺甲恶唑、咖啡因和卡马西平的厌氧转化模拟研究

为了探究药品和个人护理用品(PPCPs)在岸滤系统中的转化过程及其影响因素,采集了不同类型的河床岸滤土壤,模拟岸滤系统中的反硝化和硫还原过程,探究该过程中磺胺甲恶唑(Sulfamethoxazole,SMX)及两种共存PPCPs(咖啡因、卡马西平)的转化过程及中间产物的生成.批次培养实验结果显示,至培养周期第87 d时SMX的生物降解率达到100%,反硝化过程中SMX自第5 d开始转化为两种衍生物—D-SMX及4-nitro-SMX,反硝化反应结束两种衍生物再次还原为SMX.SMX的转化率因有机质的不同而产生差异,添加乙酸钠有机质时SMX的转化率整体高于添加富里酸有机质的转化率;硫还原条件下SMX则完全降解;咖啡因(Caffeine,CFE)的生物降解率高于50%,不同河床土壤的理化性质差异及微生物的分布差异造成CFE的吸附及降解效果有很大差异,投加潮白河沉积物样品中CFE生物降解率高于投加密云水库沉积物样品;卡马西平(Carbamazepine,CMZ)的降解率范围在20%~35%,CMZ在岸滤系统中不易发生降解.

Simulating study of anaerobic transformation of sulfamethoxazole, caffeine and carbamazepine during river bank filtration

In order to explore the transformation of PPCPs in river bank filtration system and the influencing factors on it, different soils from river bank were collected and were used to simulate denitrification and sulphate-reducing condition of river bank filtration. The transformation of sulfamethoxazole(SMX) and two coexisting PPCPs (caffeine and carbamazepine) in this system were studied. The result of anoxic water/sediment batch experiment shows that the biodegradation rate of SMX reached 100% on the 87^th day. Since the 5^th day SMX was converted to two kinds of derivatives during denitrification process, which were D-SMX and 4-nitro-SMX. After denitrification, two derivatives retransformed to SMX. The transformation rate varied with different organic matters matrix:the SMX transformation rate was rather higher when adding sodium acetate as the organic matter than that of adding fulvic acid. SMX was degraded completely in sulfur reduction condition. Biodegradation rate of caffeine(CFE) was higher than 50%. Moreover, different soils properties result in varied adsorption and degradation ability of CFE. The results show CFE biodegradation in Chaobai River bank simulating system was higher than that in Miyun Reservoir bank simulating system. Degradation rate of carbamazepine(CMZ) ranges from 20% to 35%. CMZ is not degraded or retained in river bank filtration system.