欧阳彤(1992-), 女, 主要从事水污染控制与生态修复研究, E-mail:
Ouyang Tong (1992-), main research interests: water pollution control and ecological restoration, E-mail:
Zhang Wenyi (corresponding author), professor, PhD, E-mail:
针对生活污水中内分泌干扰物(EDCs)可能引起的生物生态危害问题,以类固醇类内分泌干扰物为处理对象,应用生物生态耦合技术,进行多级AO+潜流式人工湿地处理试验,考察了水力停留时间(HRT)对CODCr、氨氮(NH4+-N)、总磷(TP)、总氮(TN)等污染物去除影响,同时,采用固相萃取法和GC-MS检测各反应器进、出水中雌酮(E1)、17β-雌二醇(E2)、雌三醇(E3)、17α-乙炔基雌二醇(EE2)4种内分泌干扰物浓度变化。结果表明,当多级AO与湿地的HRT分别为9.5 h、10.3 d时,多级AO+潜流式人工湿地对CODCr、NH4+-N、TP、TN等污染物去除率可分别达78.64%、97.16%、91.84%、90.55%,出水浓度均低于《太湖地区城镇污水处理厂及重点工业行业主要水污染物排放限值》(DB 32/1072-2017)排放浓度限值。多级AO+人工湿地对内分泌干扰物E1、E2、E3和EE2的总去除率可分别达96.04%、92.45%、85.09%、88.38%;其中,多级AO系统对E1、E2、E3和EE2的去除率分别达到75.50%、72.00%、65.08%和63.35%,且一级好氧池对4种EDCs的去除贡献最大,均为27%以上;湿地系统对前3种EDCs的去除率约为20%、EE2为25%。Alpha多样性指数分析表明,好氧池物种数量和多样性多于未加EDCs前,门分类、属分类的微生物群落物种及其丰度分析表明,群落门水平、属水平相对丰度均发生变化,其中,增加的优势菌种可能对系统中EDCs的去除起到了促进作用。
Aiming at the possible biological and ecological hazards caused by endocrine disrupting chemicals (EDCs) in domestic sewage, this study took steroid endocrine disruptors as the treatment object, and applied bio-ecological coupling technology to carry out a multi-stage AO+ subsurface flow constructed wetland treatment experiment. The effects of hydraulic residence time (HRT) on the removal of CODCr, ammonia nitrogen (NH4+-N), total phosphorus (TP) and total nitrogen (TN) were investigated. At the same time solid phase extraction (SPE) and GC-MS were used to detect the concentration changes of four endocrine disruptors, including estrone (E1), 17β-estrogen (E2), estriol (E3) and 17α-ethynylestradiol (EE2), in the effluent and inlet of each reactor. The results showed that when the HRT of multi-stage AO is 9.5h and that of wetland is about 10.3d, the removal rates of CODCr, NH4+-N, TP and TN could reach 78.64%, 97.16%, 91.84% and 90.55% respectively. The concentration is lower than the limit of discharge standard of main water pollutants for municipal wastewater treatment plant and key industries of Taihu area (DB32/1072-2017). The total removal rates of endocrine disruptors E1, E2, E3 and EE2 by multi-stage AO + constructed wetlands were 96.04%, 92.45%, 85.09% and 88.38% respectively. And the removal rates of E1, E2, E3 and EE2 by multi-stage AO system were 75.50%, 72.00%, 65.08% and 63.35% respectively. The first-stage aerobic tank in multi-stage AO contributed the most to the removal of four EDCs, all of which could reach more than 27%. The removal rate of the first three EDCs by wetland system were about 20%, and EE2 was 25%. Alpha diversity index analysis showed that the number and diversity of species in aerobic pond were more than those before EDCs were added. Species and abundance analysis of microbial communities in phylum and genus classifications showed that relative abundance of phylum and genus levels changed, and the increased dominant bacteria might play a role in promoting the removal of EDCs in the system.
内分泌干扰物(EDCs),也称为环境激素,是能进入生物体内对生物内分泌系统、生殖系统及免疫系统造成危害的新型环境污染物。随着城镇化和工业化的进行,环境中EDCs的污染正在不断加重,一定含量(ng/L水平)的EDCs会扰乱机体正常代谢,类固醇类环境雌激素则是生活污水中危害较大、较为典型的环境内分泌干扰物。Cappiello等[
据资料统计,中国众多污水处理厂出水和河流都检出不同的EDCs含量[
笔者选择生活污水中常见的4种类固醇类内分泌干扰物作为考察对象,分别为天然雌激素雌酮(E1)、17β-雌二醇(E2)、雌三醇(E3)和人工合成的用于口服避孕药使用的17α-乙炔基雌二醇(EE2),并采用无硝化液内回流多级AO+潜流式人工湿地处理含一定浓度雌激素的农村生活污水,考察组合工艺的去除效果,并分析加药前后系统内微生物群落结构变化。
试验装置由集水池、无硝化液内回流多级AO、垂直潜流式人工湿地组成,工艺流程图如
试验装置示意图
Diagram of test device
人工湿地由配水槽、湿地处理区和出水收集区组成,长宽高为1、0.6、0.65 m。湿地基质从下到上由不同粒径、不同厚度的砾石、红砖碎块、钢渣、陶粒和土壤构成,其粒径分别为40~50 mm、20~40 mm、8~10 mm、4~8 mm,其铺设厚度分别为10、25、10、10、10 cm,湿地孔隙率为41.6%。基质填充后,于土壤层后移植茭白、梭鱼草、黑麦草等植物。在组合工艺运行前使人工湿地单独运行1个月,让移植植物适应人工湿地系统环境,健康成长,并完成湿地床的挂膜。
试验原水为常州某地生活污水,水质见
试验水质指标
Test water quality index
CODCr/ | 总氮/ | 总磷/ | 氨氮/ | pH值 |
150~280 | 25~40 | 2.2~3.8 | 15~35 | 6.5~7.8 |
试验进水在该生活污水的基础上添加雌酮(E1)、雌二醇(E2)、乙炔基雌二醇(EE2)和雌激素三醇(E3)4种EDCs,浓度在35~55 μg/L之间。
试验在前端无回流多级AO的HRT为4、7、7.5、9.5、12.5 h下进行,多级AO出水由水泵提入人工湿地中,流量与进水一致,待装置稳定运行后对各反应器进出水进行水质指标检测,由试验结果得出最佳水力停留时间,在此条件下,运行装置用以去除类固醇类内分泌干扰物。
试验所需主要仪器为:ZGDCY-24S型水浴氮吹仪(上海梓桂仪器有限公司,中国),DG12D型固相萃取仪,SHZ-Ⅲ型循环水式真空泵(南京科尔仪器设备有限公司,中国),Trace ISQLT型气相色谱-质谱仪(赛默飞科技有限公司,美国)。
所用主要化学试剂:E1、E2、E3和EE2标准品(纯度≥98%,上海阿拉丁生化科技股份有限公司),BSTFA(上海阿拉丁生化科技股份有限公司),吡啶(分析纯,永华化学科技有限公司),二氯甲烷(分析纯,永华化学科技有限公司),丙酮(分析纯,国药化学试剂有限公司),甲醇(HPLC级,国药化学试剂有限公司),正己烷(分析纯,江苏强盛功能化学有限公司)。
取1 L的水样,采用0.45 μm的GF/F滤膜抽滤,用硫酸将滤液pH调到3以下。
Simon Acti-Carb SPE固相萃取柱依次用2.5 mL甲醇、3.5 mL超纯水分别活化3次。取抽滤完的1 L水样,以10 mL/min速率过固相萃取柱,再分别加入8 mL甲醇、8 mL二氯甲烷、8 mL正己烷进行洗柱,最后用10 mL的二氯甲烷和丙酮的混合溶液淋洗小柱,收集淋洗液。
将淋洗液在35~40 ℃的水浴氮吹仪中用高纯度氮气缓慢浓缩至1 mL,取100 μL浓缩液至色谱进样瓶中,再由氮气吹干,然后加入25 μL BSTFA和50 μL吡啶,于常温条件下反应20 min,进行GC-MS分析。
气质联用仪色谱柱为TG-5MS(30 m×0.25 mm×0.25 μm),气相条件如下。
GC:以氦气为载气,流速1 mL/min;不分流方式进样,进样口温度280 ℃,进样体积1 μL;柱初始温度为50 ℃,保持2 min,以12 ℃/min程序升温至260 ℃,保持8 min,再以3 ℃/min升温至280 ℃,保持5 min。
MS:接口温度280 ℃,传输线温度300 ℃,离子源为EI源,温度250 ℃,电子轰击能量70 eV,溶剂延迟时间12 min,以全扫描模式定性,扫描范围参数
根据其衍生产物的特征碎片离子分布特征从而来确定目标产物的实际浓度,衍生产物的实际参数见
衍生物的相应参数
corresponding parameters of derivative products
衍生产物 | 保留时 | 特征碎片 | 线性回归方程 |
注: | |||
TMS-E1 | 23.58 | 342、327、285 | |
di-TMS-E2 | 24.24 | 416、401、285 | |
di-TMS-EE2 | 26.25 | 440、425、285 | |
Tri-TMS-E3 | 28.37 | 504、489、285 |
衍生产物的总离子特征分布图
Total ion characteristic distribution of derivative products
采集投加EDCs后运行2个月以内的好氧池污泥,冷冻保存,委托生工生物工程(上海)股份有限公司进行454焦磷酸测序测定,并与之前测定的未加任何内分泌干扰物和菌剂的污泥进行对比。
随着HRT的增加,前端无回流多级AO对CODCr的去除率呈轻微上升趋势。HRT对CODCr的去除效果影响不大。由
HRT对CODCr去除的影响
Effect of hydraulic retention time on CODCr removal
由
HRT对NH4+-N去除的影响
Effect of hydraulic retention time onNH4+-N removal
由
HRT对TN去除的影响
Effect of hydraulic retention time on TN removal
据Liu等[
HRT对TP去除的影响
Effect of hydraulic retention time on TP removal
在整个试验检测周期中,多级AO+潜流式人工湿地保持连续进水,且进出水水质稳定,其对4种雌激素的去除效果如
组合工艺各反应器EDCs出水浓度
EDCs effluent concentration in each stage of the combined process
由
各沿程对EDCs的去除率
Removal rate of EDCs along each path
Alpha多样性指数[
样品多样性统计
Sample diversity statistics
Samples | Chao1 | ACE | Shannon | Simpson | OTU |
好氧池 | 0 955.833 333 3 | 0 938.042 865 8 | 4.709 739 771 | 0.047 731 76 | 0 815 |
好氧池(投加EDCs) | 1 656.980 488 | 2 060.337 924 | 4.558 572 | 0.030 642 | 1 188 |
加雌激素运行35 d后的好氧池微生物群落结构(门水平)如
微生物群落结构变化图(门)
Comparison of microbial community structure (phylum)
微生物群落结构变化图(属)
Comparison of microbial community structure (genus)
McAdam等[
1) 当多级AO HRT为9.5 h、湿地HRT为10.3 d时,组合工艺对CODCr、NH4+-N、TN和TP污染物去除率可分别达78.64%、97.16%、91.84%、90.55%,满足了太湖流域污水的高标准排放要求。无回流多级AO+潜流式人工湿地组合工艺对E1、E2、E3和EE2这4种EDCs有较高的去除效果,去除率分别达96.04%、92.45%、85.09%、88.38%,其中,E1去除效果最好,而E3去除率偏低,可能是因为E3是E1和E2生物降解过程中的中间产物。
2) EDCs的去除主要依靠活性污泥吸附与微生物降解。生物单元多级AO中,一级好氧池和二级缺氧池对4种雌激素的去除贡献较大,表明好氧或兼性厌氧菌对EDCs的去除起着重要作用。生态单元中,湿地基质的吸附、湿地植物发达根系泌养和根系微生物对于4种EDCs的去除效率可在生物单元基础上提高20%~25%。
3) Alpha多样性指数分析表明,加入EDCs后运行的好氧池物种数量和多样性要多于未加前,门分类和属分类的微生物群落物种及其丰度分析表明,变形菌门丰度较之前增加了近13%,厚壁菌门增加了近15.6%,增加的反硝化菌属
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