人工湿地根区微环境调控强化雌激素去除的研究

发布时间：2018-07-04 17:17

本文选题：人工湿地 + 雌酮(E1)　；参考：《东南大学》2015年硕士论文

【摘要】：近年来,人们发现环境中极微量的类固醇雌激素(Steroidal Estrogens, SEs)就能危害人和动物的健康,目前以人工湿地法去除SEs的研究甚少。本论文以雌酮(Estrone, El)和17α-乙炔基雌二醇(17a-Ethinylestradiol, EE2)为研究对象,从调整根区微环境的角度,考察根系分泌物浓度、植物种类和电化学作用对人工湿地强化去除SEs的研究。研究美人蕉、芦苇的根系分泌物和根系浸出液的成分,主要结论如下：芦苇的根系分泌能力明显高于美人蕉,且芦苇的根系浸出液和根系分泌物中均含有较多的氨基酸(包括DL-瓜氨酸和L-精氨酸)和多糖；两者根系分泌物中均含有生物碱等次生代谢物质；由于根系浸出液与根系分泌物主要成分组成类似,后续实验以添加根系浸出液来模拟根系分泌物的增加。为考察根区根系分泌物的影响,三组人工湿地中分别添加不同浓度根系浸出液(c(MD)=0mg/L, c(MZ)=14mg/L, c(MG)=28mg/L),研究其对SEs等污染物的去除,主要结论如下：基质未达饱和前,E1和EE2均先发生吸附作用,EE2吸附较快且与E1发生竞争吸附。适当添加一定浓度的根系浸出液,即模拟根系分泌物适当增多时,有利于E1、EE2、TOC、TN、TP的去除,MZ对E1、EE2最高去除率分别达88.2%和72.6%；硝化过程中所分泌的氨单加氧酶或非特异性降解酶可能有利于雌激素的降解；生物膜脱氢酶活性大小依次为MZ MD MG,根系分泌物的增加有利于提高微生物的活性,但浓度过高反而会影响微生物的活性。为考察根区植物种类的影响,两组人工湿地中分别种植美人蕉和芦苇,研究其对SEs等污染物的去除,主要结论如下：E1的去除率比EE2更易受植物种类的影响,因为植物的根系分泌物越多越丰富,越易使细菌大量繁殖,E1去除率受异养菌数量影响较大；LZ中细菌数量明显高于MZ,AOB(氨氧化细菌)数量稍高于MZ,可能是因为LZ分泌的含氮小分子有机物更多,NOB数量接近MZ的两倍,是因为芦苇的根系分泌物偏中性,更适宜硝化菌的生长,SEs去除率与湿地中硝化作用强度正相关；LZ湿地基质生物膜的脱氢酶活性大于MZ,可能是因为美人蕉的根系分泌物呈酸性,而脱氢酶最适反应条件为pH中性。为考察根区生物电化学作用的影响,构建两组微生物燃料电池型湿地(有植物MFCW1系统和无植物MFCW2系统),研究其对SEs等污染物的去除,探究其产电性能,主要结论如下：MFCW1和MFCW2对E1、EE2的去除率始终高于80%,去除效果明显优于普通人工湿地MD,可能是因为SEs极易吸附存填料以及阳极活性炭上接种的活性污泥上；MFCW(微生物燃料电池型湿地)对TOC、TN和TP的去除效果均强于MD,可能是因为细胞膜通透性和催化性能提高而促进了微生物对营养物质的利用；根系泌氧作用使得阴极区的溶氧浓度提高,从而使MFCW1的阴极电势高于MFCW2; MFCW1对SEs、TOC、TN、TP的去除效果略强于MFCW2,是凼为植物对氮磷具有吸收或吸附作用,且根系分泌物能提高微生物数量和活性；MFCW1和MFCW2阴极基质上的细菌密度与普通人工湿地MD接近,而阳极基质上的细菌密度超过MD的两倍：MFCW1和MFCW2中G细菌(G.sulfurreducens)和β菌(BetaProteobacteria)密度较大,说明MFCW有良好的产电性能。
[Abstract]:In recent years , it has been found that a very small amount of steroid estrogen in the environment can harm the health of human beings and animals . In this paper , we study the effects of root exudates , plant species and electrochemical effects on artificial wetland . The main conclusions are as follows : Estrone ( El ) and 17伪 - ethynylethyestradiol ( EE2 ) are the research objects . The main conclusions are as follows : The root exudates and root exudates of the reed are obviously higher than those of Canna , and the root exudates and root exudates of the reed contain more amino acids ( including DL - melon and L - arginine ) and polysaccharides ;
The root exudates contained secondary metabolites such as alkaloids .
In order to study the effects of root exudates on root exudates , the root exudates ( c ( MD ) = 0 mg / L , c ( MZ ) = 14 mg / L , c ( MG ) = 28 mg / L were added to the root exudates .
The ammonia monooxygenase or non - specific degrading enzyme secreted during the nitrification process may be beneficial to the degradation of estrogen ;
In order to study the effect of the plant species , the removal rate of E1 was more easily affected by plant species . The more abundant the root exudates of plants , the more susceptible the bacteria could multiply , and the removal rate of E1 was greatly affected by the quantity of isotrophic bacteria .
The quantity of bacteria was obviously higher than that of MZ , and AOB ( ammonia oxidizing bacteria ) was slightly higher than MZ , probably because of the more nitrogen - containing small molecule organic matters secreted by lz , the number of NOB was nearly twice that of MZ , because the root exudates of reed were more neutral , more suitable for the growth of nitrification bacteria , and the removal rate of nitrification was positively correlated with the strength of nitrification in the wetland ;
In order to study the effect of biological electrochemistry in root zone , two groups of microbial fuel cell type wetlands ( plant MFCW1 system and non - plant MFCW2 system ) were constructed . The results showed that the removal rates of the MFCW1 and MFCW2 for E1 and EE2 were always higher than 80 % , and the removal effect was obviously better than that of the conventional artificial wetland MD , possibly because of the easy adsorption of the filler and the activated sludge inoculated on the anode active carbon ;
The removal of TOC , TN and TP by MFCW ( microbial fuel cell type wetland ) was stronger than that of MD , which could improve the utilization of nutrients by membrane permeability and catalytic performance .
The results showed that the cathode potential of MFCW1 was higher than that of MFCW2 , and the removal effect of MFCW1 was slightly stronger than that of MFCW2 .
The density of bacteria on the cathode substrate of MFCW1 and MFCW2 is close to that of common artificial wetland , while the density of bacteria on the anode substrate is twice as large as that of MD . The density of G bacteria ( G . ) reducens and BetaProteomics in MFCW1 and MFCW2 is larger , which indicates that MFCW1 has good electrical performance .
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703

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